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Special Issue "Abiotic and Biotic Stress Tolerance Mechanisms in Plants"

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A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Biochemistry, Molecular Biology and Biophysics".

Deadline for manuscript submissions: closed (31 January 2013)

Special Issue Editor

Guest Editor
Prof. Dr. Maria Hrmova

Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond SA 5064, Australia
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Special Issue Information

Dear Colleagues,

Abiotic stresses such as drought, salinity and mineral toxicity negatively impact growth, development, yield and seed quality of plants. Similarly, large losses of grain yields in plants occur as a result of pathogen attack, in particular during vulnerable stages of grain development and germination. Stress perception and plant response occurs via signal transduction pathways that regulate expression of several classes of stress responsive genes. Products of these genes include those that are directly involved in plant protection and those that fulfil regulatory functions. The first group of the gene products include chaperones, osmotins, anti-freeze proteins, mRNA binding proteins, enzymes involved in osmolyte biosynthesis, water channel proteins, sugar and proline transport proteins, detoxification enzymes and a variety of proteases, as well as a range of antimicrobial, insecticidal and other proteins and peptides. The proteins with regulatory function involve transcription factors and those that are engaged in signal transduction pathways, such as protein kinases and hormone biosynthetic enzymes. Both classes of genes encoding these proteins are being investigated using the tools of forward and reverse genetics. Once the stress response pathways are defined and the key players during the plant response to stress are demarcated by forward genetics approaches. Gene function can be enhanced through reverse genetics approaches such as genetic engineering or novel alleles can be sought through germplasm screening or mutagenesis. The latter avenues offer alternatives to traditional breeding. The new knowledge acquired through research of abiotic and biotic stress tolerance mechanisms in plants will help in the application of stress responsive determinants and in engineering plants with enhanced tolerance to stress.

Dr. Maria Hrmova
Guest Editor

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Keywords

  • agricultural biotechnology
  • counteracting abiotic and biotic stresses
  • disease and stress resistant plants
  • food security and safety
  • molecular structure
  • natural variation
  • regulation of plant responses under stress factors
  • role of genetic engineering in stress tolerance
  • stress responsive transcription factors and other proteins

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Published Papers (54 papers)

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Open AccessArticle Impacts of pr-10a Overexpression at the Molecular and the Phenotypic Level
Int. J. Mol. Sci. 2013, 14(7), 15141-15166; doi:10.3390/ijms140715141
Received: 18 April 2013 / Revised: 19 May 2013 / Accepted: 23 May 2013 / Published: 22 July 2013
Cited by 6 | PDF Full-text (1565 KB) | HTML Full-text | XML Full-text
Abstract
Biotechnological approaches using genetic modifications such as homologous gene overexpression can be used to decode gene functions under well-defined circumstances. However, only the recording of the resulting phenotypes allows inferences about the impact of the modification on the organisms’ evolutionary, ecological or economic
[...] Read more.
Biotechnological approaches using genetic modifications such as homologous gene overexpression can be used to decode gene functions under well-defined circumstances. However, only the recording of the resulting phenotypes allows inferences about the impact of the modification on the organisms’ evolutionary, ecological or economic performance. We here compare a potato wild-type cell line with two genetically engineered cell cultures homologously overexpressing Pathogenesis Related Protein 10a (pr-10a). A detailed analysis of the relative gene-expression patterns of pr-10a and its regulators sebf and pti4 over time provides insights into the molecular response of heterotrophic cells to distinct osmotic and salt-stress conditions. Furthermore, this system serves as an exemplar for the tracing of respiration kinetics as a faster and more sensitive alternative to the laborious and time-consuming recording of growth curves. The utility and characteristics of the resulting data type and the requirements for its appropriate analysis are figured out. It is demonstrated how this novel type of phenotypic information together with the gene-expression-data provides valuable insights into the effect of genetic modifications on the behaviour of cells on both the molecular and the macroscopic level. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Alleviation of Osmotic Stress Effects by Exogenous Application of Salicylic or Abscisic Acid on Wheat Seedlings
Int. J. Mol. Sci. 2013, 14(7), 13171-13193; doi:10.3390/ijms140713171
Received: 29 March 2013 / Revised: 15 May 2013 / Accepted: 27 May 2013 / Published: 26 June 2013
Cited by 15 | PDF Full-text (657 KB) | HTML Full-text | XML Full-text
Abstract
The aim of the study was to assess the role of salicylic acid (SA) and abscisic acid (ABA) in osmotic stress tolerance of wheat seedlings. This was accomplished by determining the impact of the acids applied exogenously on seedlings grown under osmotic stress
[...] Read more.
The aim of the study was to assess the role of salicylic acid (SA) and abscisic acid (ABA) in osmotic stress tolerance of wheat seedlings. This was accomplished by determining the impact of the acids applied exogenously on seedlings grown under osmotic stress in hydroponics. The investigation was unique in its comprehensiveness, examining changes under osmotic stress and other conditions, and testing a number of parameters simultaneously. In both drought susceptible (SQ1) and drought resistant (CS) wheat cultivars, significant physiological and biochemical changes were observed upon the addition of SA (0.05 mM) or ABA (0.1 μM) to solutions containing half-strength Hoagland medium and PEG 6000 (−0.75 MPa). The most noticeable result of supplementing SA or ABA to the medium (PEG + SA and PEG + ABA) was a decrease in the length of leaves and roots in both cultivars. While PEG treatment reduced gas exchange parameters, chlorophyll content in CS, and osmotic potential, and conversely, increased lipid peroxidation, soluble carbohydrates in SQ1, proline content in both cultivars and total antioxidants activity in SQ1, PEG + SA or PEG + ABA did not change the values of these parameters. Furthermore, PEG caused a two-fold increase of endogenous ABA content in SQ1 and a four-fold increase in CS. PEG + ABA increased endogenous ABA only in SQ1, whereas PEG + SA caused a greater increase of ABA content in both cultivars compared to PEG. In PEG-treated plants growing until the harvest, a greater decrease of yield components was observed in SQ1 than in CS. PEG + SA, and particularly PEG + ABA, caused a greater increase of these yield parameters in CS compared to SQ1. In conclusion, SA and ABA ameliorate, particularly in the tolerant wheat cultivar, the harmful effects and after effects of osmotic stress induced by PEG in hydroponics through better osmotic adjustment achieved by an increase in proline and carbohydrate content as well as by an increase in antioxidant activity. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Microarray Analysis of Transcriptional Responses to Abscisic Acid and Salt Stress in Arabidopsis thaliana
Int. J. Mol. Sci. 2013, 14(5), 9979-9998; doi:10.3390/ijms14059979
Received: 18 January 2013 / Revised: 11 April 2013 / Accepted: 28 April 2013 / Published: 10 May 2013
Cited by 8 | PDF Full-text (1474 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Abscisic acid (ABA) plays a crucial role in plant responses to abiotic stress. To investigate differences in plant responses to salt and ABA stimulus, differences in gene expression in Arabidopsis in response to salt and ABA were compared using an Agilent oligo microarray.
[...] Read more.
Abscisic acid (ABA) plays a crucial role in plant responses to abiotic stress. To investigate differences in plant responses to salt and ABA stimulus, differences in gene expression in Arabidopsis in response to salt and ABA were compared using an Agilent oligo microarray. A total of 144 and 139 genes were significantly up- and downregulated, respectively, under NaCl stress, while 406 and 381 genes were significantly up- and downregulated, respectively, under ABA stress conditions. In addition, 31 genes were upregulated by both NaCl and ABA stresses, and 23 genes were downregulated by these stressors, suggesting that these genes may play similar roles in plant responses to salt and ABA stress. Gene ontology (GO) analysis revealed four subgroups of genes, including genes in the GO categories “Molecular transducer activity”, “Growth”, “Biological adhesion” and “Pigmentation”, which were expressed in response to ABA stress but not NaCl stress. In addition, genes that play specific roles during salt or ABA stress were identified. Our results may help elucidate differences in the response of plants to salt and ABA stress. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessArticle Two Volatile Organic Compounds Trigger Plant Self-Defense against a Bacterial Pathogen and a Sucking Insect in Cucumber under Open Field Conditions
Int. J. Mol. Sci. 2013, 14(5), 9803-9819; doi:10.3390/ijms14059803
Received: 13 March 2013 / Revised: 27 April 2013 / Accepted: 3 May 2013 / Published: 8 May 2013
Cited by 24 | PDF Full-text (365 KB) | HTML Full-text | XML Full-text
Abstract
Systemic acquired resistance (SAR) is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be
[...] Read more.
Systemic acquired resistance (SAR) is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC)-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Drought Stress Acclimation Imparts Tolerance to Sclerotinia sclerotiorum and Pseudomonas syringae in Nicotiana benthamiana
Int. J. Mol. Sci. 2013, 14(5), 9497-9513; doi:10.3390/ijms14059497
Received: 12 March 2013 / Revised: 13 April 2013 / Accepted: 22 April 2013 / Published: 2 May 2013
Cited by 16 | PDF Full-text (2845 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Acclimation of plants with an abiotic stress can impart tolerance to some biotic stresses. Such a priming response has not been widely studied. In particular, little is known about enhanced defense capacity of drought stress acclimated plants to fungal and bacterial pathogens. Here
[...] Read more.
Acclimation of plants with an abiotic stress can impart tolerance to some biotic stresses. Such a priming response has not been widely studied. In particular, little is known about enhanced defense capacity of drought stress acclimated plants to fungal and bacterial pathogens. Here we show that prior drought acclimation in Nicotiana benthamiana plants imparts tolerance to necrotrophic fungus, Sclerotinia sclerotiorum, and also to hemi-biotrophic bacterial pathogen, Pseudomonas syringae pv. tabaci. S. sclerotiorum inoculation on N. benthamiana plants acclimated with drought stress lead to less disease-induced cell death compared to non-acclimated plants. Furthermore, inoculation of P. syringae pv. tabaci on N. benthamiana plants acclimated to moderate drought stress showed reduced disease symptoms. The levels of reactive oxygen species (ROS) in drought acclimated plants were highly correlated with disease resistance. Further, in planta growth of GFPuv expressing P. syringae pv. tabaci on plants pre-treated with methyl viologen showed complete inhibition of bacterial growth. Taken together, these experimental results suggested a role for ROS generated during drought acclimation in imparting tolerance against S. sclerotiorum and P. syringae pv. tabaci. We speculate that the generation of ROS during drought acclimation primed a defense response in plants that subsequently caused the tolerance against the pathogens tested. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Antioxidant Systems from Pepper (Capsicum annuum L.): Involvement in the Response to Temperature Changes in Ripe Fruits
Int. J. Mol. Sci. 2013, 14(5), 9556-9580; doi:10.3390/ijms14059556
Received: 21 February 2013 / Revised: 18 April 2013 / Accepted: 23 April 2013 / Published: 2 May 2013
Cited by 7 | PDF Full-text (1162 KB) | HTML Full-text | XML Full-text
Abstract
Sweet pepper is susceptible to changes in the environmental conditions, especially temperatures below 15 °C. In this work, two sets of pepper fruits (Capsicum annuum L.) which underwent distinct temperature profiles in planta were investigated. Accordingly, two harvesting times corresponding to each
[...] Read more.
Sweet pepper is susceptible to changes in the environmental conditions, especially temperatures below 15 °C. In this work, two sets of pepper fruits (Capsicum annuum L.) which underwent distinct temperature profiles in planta were investigated. Accordingly, two harvesting times corresponding to each set were established: Harvest 1, whose fruits developed and ripened at 14.9 °C as average temperature; and Harvest 2, with average temperature of 12.4 °C. The oxidative metabolism was analyzed in all fruits. Although total ascorbate content did not vary between Harvests, a shift from the reduced to the oxidized form (dehydroascorbate), accompanied by a higher ascorbate peroxidase activity, was observed in Harvest 2 with respect to Harvest 1. Moreover, a decrease of the ascorbate-generating enzymatic system, the γ-galactono-lactone dehydrogenase, was found at Harvest 2. The activity values of the NADP-dependent dehydrogenases analyzed seem to indicate that a lower NADPH synthesis may occur in fruits which underwent lower temperature conditions. In spite of the important changes observed in the oxidative metabolism in fruits subjected to lower temperature, no oxidative stress appears to occur, as indicated by the lipid peroxidation and protein oxidation profiles. Thus, the antioxidative systems of pepper fruits seem to be involved in the response against temperature changes. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessArticle Characterization of Rice NADPH Oxidase Genes and Their Expression under Various Environmental Conditions
Int. J. Mol. Sci. 2013, 14(5), 9440-9458; doi:10.3390/ijms14059440
Received: 29 January 2013 / Revised: 4 April 2013 / Accepted: 17 April 2013 / Published: 29 April 2013
Cited by 12 | PDF Full-text (2673 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Plasma membrane NADPH oxidases (Noxs) are key producers of reactive oxygen species under both normal and stress conditions in plants. We demonstrate that at least eleven genes in the genome of rice (Oryza sativa L.) were predicted to encode Nox proteins, including
[...] Read more.
Plasma membrane NADPH oxidases (Noxs) are key producers of reactive oxygen species under both normal and stress conditions in plants. We demonstrate that at least eleven genes in the genome of rice (Oryza sativa L.) were predicted to encode Nox proteins, including nine genes (OsNox19) that encode typical Noxs and two that encode ancient Nox forms (ferric reduction oxidase 1 and 7, OsFRO1 and OsFRO7). Phylogenetic analysis divided the Noxs from nine plant species into six subfamilies, with rice Nox genes distributed among subfamilies I to V. Gene expression analysis using semi-quantitative RT-PCR and real-time qRT-PCR indicated that the expression of rice Nox genes depends on organs and environmental conditions. Exogenous calcium strongly stimulated the expression of OsNox3, OsNox5, OsNox7, and OsNox8, but depressed the expression of OsFRO1. Drought stress substantially upregulated the expression of OsNox13, OsNox5, OsNox9, and OsFRO1, but downregulated OsNox6. High temperature upregulated OsNox59, but significantly downregulated OsNox13 and OsFRO1. NaCl treatment increased the expression of OsNox2, OsNox8, OsFRO1, and OsFRO7, but decreased that of OsNox1, OsNox3, OsNox5, and OsNox6. These results suggest that the expression profiles of rice Nox genes have unique stress-response characteristics, reflecting their related but distinct functions in response to different environmental stresses. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessArticle Improved Nutritive Quality and Salt Resistance in Transgenic Maize by Simultaneously Overexpression of a Natural Lysine-Rich Protein Gene, SBgLR, and an ERF Transcription Factor Gene, TSRF1
Int. J. Mol. Sci. 2013, 14(5), 9459-9474; doi:10.3390/ijms14059459
Received: 31 December 2012 / Revised: 16 April 2013 / Accepted: 16 April 2013 / Published: 29 April 2013
Cited by 11 | PDF Full-text (3676 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Maize (Zea mays L.), as one of the most important crops in the world, is deficient in lysine and tryptophan. Environmental conditions greatly impact plant growth, development and productivity. In this study, we used particle bombardment mediated co-transformation to obtain marker-free transgenic
[...] Read more.
Maize (Zea mays L.), as one of the most important crops in the world, is deficient in lysine and tryptophan. Environmental conditions greatly impact plant growth, development and productivity. In this study, we used particle bombardment mediated co-transformation to obtain marker-free transgenic maize inbred X178 lines harboring a lysine-rich protein gene SBgLR from potato and an ethylene responsive factor (ERF) transcription factor gene, TSRF1, from tomato. Both of the target genes were successfully expressed and showed various expression levels in different transgenic lines. Analysis showed that the protein and lysine content in T1 transgenic maize seeds increased significantly. Compared to non-transformed maize, the protein and lysine content increased by 7.7% to 24.38% and 8.70% to 30.43%, respectively. Moreover, transgenic maize exhibited more tolerance to salt stress. When treated with 200 mM NaCl for 48 h, both non-transformed and transgenic plant leaves displayed wilting and losing green symptoms and dramatic increase of the free proline contents. However, the degree of control seedlings was much more serious than that of transgenic lines and much more increases of the free proline contents in the transgenic lines than that in the control seedlings were observed. Meanwhile, lower extent decreases of the chlorophyll contents were detected in the transgenic seedlings. Quantitative RT-PCR was performed to analyze the expression of ten stress-related genes, including stress responsive transcription factor genes, ZmMYB59 and ZmMYC1, proline synthesis related genes, ZmP5CS1 and ZmP5CS2, photosynthesis-related genes, ZmELIP, ZmPSI-N, ZmOEE, Zmrbcs and ZmPLAS, and one ABA biosynthesis related gene, ZmSDR. The results showed that with the exception of ZmP5CS1 and ZmP5CS2 in line 9–10 and 19–11, ZmMYC1 in line 19–11 and ZmSDR in line 19–11, the expression of other stress-related genes were inhibited in transgenic lines under normal conditions. After salt treatment, the expressions of the ten stress-related genes were significantly induced in both wild-type (WT) and transgenic lines. However, compared to WT, the increases of ZmP5CS1 in all these three transgenic lines and ZmP5CS2 in line 9–10 were less than WT plants. This study provides an effective approach of maize genetic engineering for improved nutritive quality and salt tolerance. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Differential Activity of Plasma and Vacuolar Membrane Transporters Contributes to Genotypic Differences in Salinity Tolerance in a Halophyte Species, Chenopodium quinoa
Int. J. Mol. Sci. 2013, 14(5), 9267-9285; doi:10.3390/ijms14059267
Received: 22 February 2013 / Revised: 13 April 2013 / Accepted: 15 April 2013 / Published: 29 April 2013
Cited by 28 | PDF Full-text (2251 KB) | HTML Full-text | XML Full-text
Abstract
Halophytes species can be used as a highly convenient model system to reveal key ionic and molecular mechanisms that confer salinity tolerance in plants. Earlier, we reported that quinoa (Chenopodium quinoa Willd.), a facultative C3 halophyte species, can efficiently control the activity
[...] Read more.
Halophytes species can be used as a highly convenient model system to reveal key ionic and molecular mechanisms that confer salinity tolerance in plants. Earlier, we reported that quinoa (Chenopodium quinoa Willd.), a facultative C3 halophyte species, can efficiently control the activity of slow (SV) and fast (FV) tonoplast channels to match specific growth conditions by ensuring that most of accumulated Na+ is safely locked in the vacuole (Bonales-Alatorre et al. (2013) Plant Physiology). This work extends these finding by comparing the properties of tonoplast FV and SV channels in two quinoa genotypes contrasting in their salinity tolerance. The work is complemented by studies of the kinetics of net ion fluxes across the plasma membrane of quinoa leaf mesophyll tissue. Our results suggest that multiple mechanisms contribute towards genotypic differences in salinity tolerance in quinoa. These include: (i) a higher rate of Na+ exclusion from leaf mesophyll; (ii) maintenance of low cytosolic Na+ levels; (iii) better K+ retention in the leaf mesophyll; (iv) a high rate of H+ pumping, which increases the ability of mesophyll cells to restore their membrane potential; and (v) the ability to reduce the activity of SV and FV channels under saline conditions. These mechanisms appear to be highly orchestrated, thus enabling the remarkable overall salinity tolerance of quinoa species. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Characteristic of the Pepper CaRGA2 Gene in Defense Responses against Phytophthora capsici Leonian
Int. J. Mol. Sci. 2013, 14(5), 8985-9004; doi:10.3390/ijms14058985
Received: 25 January 2013 / Revised: 15 April 2013 / Accepted: 16 April 2013 / Published: 25 April 2013
Cited by 13 | PDF Full-text (1174 KB) | HTML Full-text | XML Full-text
Abstract
The most significant threat to pepper production worldwide is the Phytophthora blight, which is caused by the oomycete pathogen, Phytophthora capsici Leonian. In an effort to help control this disease, we isolated and characterized a P. capsici resistance gene, CaRGA2, from a
[...] Read more.
The most significant threat to pepper production worldwide is the Phytophthora blight, which is caused by the oomycete pathogen, Phytophthora capsici Leonian. In an effort to help control this disease, we isolated and characterized a P. capsici resistance gene, CaRGA2, from a high resistant pepper (C. annuum CM334) and analyzed its function by the method of real-time PCR and virus-induced gene silencing (VIGS). The CaRGA2 has a full-length cDNA of 3,018 bp with 2,874 bp open reading frame (ORF) and encodes a 957-aa protein. The protein has a predicted molecular weight of 108.6 kDa, and the isoelectric point is 8.106. Quantitative real-time PCR indicated that CaRGA2 expression was rapidly induced by P. capsici. The gene expression pattern was different between the resistant and susceptible cultivars. CaRGA2 was quickly expressed in the resistant cultivar, CM334, and reached to a peak at 24 h after inoculation with P. capsici, five-fold higher than that of susceptible cultivar. Our results suggest that CaRGA2 has a distinct pattern of expression and plays a critical role in P. capsici stress tolerance. When the CaRGA2 gene was silenced via VIGS, the resistance level was clearly suppressed, an observation that was supported by semi-quantitative RT-PCR and detached leave inoculation. VIGS analysis revealed their importance in the surveillance to P. capsici in pepper. Our results support the idea that the CaRGA2 gene may show their response in resistance against P. capsici. These analyses will aid in an effort towards breeding for broad and durable resistance in economically important pepper cultivars. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle The Expression of Millettia pinnata Chalcone Isomerase in Saccharomyces cerevisiae Salt-Sensitive Mutants Enhances Salt-Tolerance
Int. J. Mol. Sci. 2013, 14(5), 8775-8786; doi:10.3390/ijms14058775
Received: 31 January 2013 / Revised: 18 March 2013 / Accepted: 1 April 2013 / Published: 24 April 2013
Cited by 5 | PDF Full-text (586 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The present study demonstrates a new Millettia pinnata chalcone isomerase (MpCHI) whose transcription level in leaf was confirmed to be enhanced after being treated by seawater or NaCl (500 mM) via transcriptome sequencing and Real-Time Quantitative Reverse Transcription PCR (QRT-PCR) analyses. Its full
[...] Read more.
The present study demonstrates a new Millettia pinnata chalcone isomerase (MpCHI) whose transcription level in leaf was confirmed to be enhanced after being treated by seawater or NaCl (500 mM) via transcriptome sequencing and Real-Time Quantitative Reverse Transcription PCR (QRT-PCR) analyses. Its full length cDNA (666 bp) was obtained by 3'-end and 5'-end Rapid Amplification of cDNA Ends (RACE). The analysis via NCBI BLAST indicates that both aminoacid sequence and nucleotide sequence of the MpCHI clone share high homology with other leguminous CHIs (73%–86%). Evolutionarily, the phylogenic analysis further revealed that the MpCHI is a close relative of leguminous CHIs. The MpCHI protein consists of 221 aminoacid (23.64 KDa), whose peptide length, amino acid residues of substrate-binding site and reactive site are very similar to other leguminous CHIs reported previously. Two pYES2-MpCHI transformed salt-sensitive Saccharomyces cerevisiae mutants (Δnha1 and Δnhx1) showed improved salt-tolerance significantly compared to pYES2-vector transformed yeast mutants, suggesting the MpCHI or the flavonoid biosynthesis pathway could regulate the resistance to salt stress in M. pinnata. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Two Common Bean Genotypes with Contrasting Response to Phosphorus Deficiency Show Variations in the microRNA 399-Mediated PvPHO2 Regulation within the PvPHR1 Signaling Pathway
Int. J. Mol. Sci. 2013, 14(4), 8328-8344; doi:10.3390/ijms14048328
Received: 20 February 2013 / Revised: 2 April 2013 / Accepted: 2 April 2013 / Published: 16 April 2013
Cited by 7 | PDF Full-text (497 KB) | HTML Full-text | XML Full-text
Abstract
Crop production of the important legume, the common bean (Phaseolus vulgaris), is often limited by low phosphorus (P) in the soil. The genotypes, BAT477 and DOR364, of the common bean have contrasting responses to P starvation. Plants from the BAT477
[...] Read more.
Crop production of the important legume, the common bean (Phaseolus vulgaris), is often limited by low phosphorus (P) in the soil. The genotypes, BAT477 and DOR364, of the common bean have contrasting responses to P starvation. Plants from the BAT477 P deficiency tolerant genotype showed higher phosphate content and root biomass as compared to the DOR364 plants under P starvation. The PvPHR1 transcription factor-signaling pathway plays an essential role in the response to P starvation. PvPHO2, a negative regulator of this pathway, encodes an ubiquitin E2 conjugase that promotes degradation of P-responsive proteins and is the target gene of PvmiR399. PvPHO2 is downregulated in BAT477 plants under P deficiency, while such a response is not observed in P-starved DOR364 plants. Five putative PvmiR399 binding sites were identified in the 5' UTR region in both genotypes. While four sites showed an identical DNA sequence, the fifth (binding site of PvPHO2 one) showed three base changes and higher complementarity scores in DOR364 as compared to BAT477. Modified 5'RACE experiments indicated that PvmiR399 binding and/or processing was affected in DOR364 P-starved plants. We propose that a less efficient cleavage of the PvPHO2 mRNA directed by PvmiR399 would result in a higher PvPHO2-mediated degradation of P-responsive proteins in the DOR364 genotype with decreased P deficiency tolerance. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Detection of Quantitative Trait Loci (QTLs) for Resistances to Small Brown Planthopper and Rice Stripe Virus in Rice Using Recombinant Inbred Lines
Int. J. Mol. Sci. 2013, 14(4), 8406-8421; doi:10.3390/ijms14048406
Received: 18 January 2013 / Revised: 5 April 2013 / Accepted: 9 April 2013 / Published: 16 April 2013
Cited by 2 | PDF Full-text (479 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Small brown planthopper (SBPH) and rice stripe virus (RSV) disease transmitted by SBPH cause serious damage to rice (Oryza sativa L.) in China. In the present study, we screened 312 rice accessions for resistance to SBPH. The indica variety, N22, is highly
[...] Read more.
Small brown planthopper (SBPH) and rice stripe virus (RSV) disease transmitted by SBPH cause serious damage to rice (Oryza sativa L.) in China. In the present study, we screened 312 rice accessions for resistance to SBPH. The indica variety, N22, is highly resistant to SBPH. One hundred and eighty two recombinant inbred lines (RILs) derived from a cross of N22 and the highly susceptible variety, USSR5, were used for quantitative trait locus (QTL) analysis of resistances to SBPH and RSV. In a modified seedbox screening test, three QTLs for SBPH resistance, qSBPH2, qSBPH3 and qSBPH7.1, were mapped on chromosomes 2, 3 and 7, a total explaining 35.1% of the phenotypic variance. qSBPH7.2 and qSBPH11.2, conferring antibiosis against SBPH, were detected on chromosomes 7 and 11 and accounted for 20.7% of the total phenotypic variance. In addition, qSBPH5 and qSBPH7.3, expressing antixenosis to SBPH, were detected on chromosomes 5 and 7, explaining 23.9% of the phenotypic variance. qSBPH7.1, qSBPH7.2 and qSBPH7.3, located in the same region between RM234 and RM429 on chromosome 7, using three different phenotyping methods indicate that the locus or region plays a major role in conferring resistance to SBPH in N22. Moreover, three QTLs, qSTV4, qSTV11.1 and qSTV11.2, for RSV resistance were detected on chromosomes 4 and 11. qSTV11.1 and qSTV11.2 are located in the same region between RM287 and RM209 on chromosome 11. Molecular markers spanning these QTLs should be useful in the development of varieties with resistance to SBPH and RSV. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Proteins Involved in Distinct Phases of Cold Hardening Process in Frost Resistant Winter Barley (Hordeum vulgare L.) cv Luxor
Int. J. Mol. Sci. 2013, 14(4), 8000-8024; doi:10.3390/ijms14048000
Received: 21 January 2013 / Revised: 28 March 2013 / Accepted: 29 March 2013 / Published: 12 April 2013
Cited by 9 | PDF Full-text (3138 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Winter barley is an economically important cereal crop grown in higher latitudes and altitudes where low temperatures represent an important environmental constraint limiting crop productivity. In this study changes in proteome of leaves and crowns in a frost tolerant winter barley cv. Luxor
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Winter barley is an economically important cereal crop grown in higher latitudes and altitudes where low temperatures represent an important environmental constraint limiting crop productivity. In this study changes in proteome of leaves and crowns in a frost tolerant winter barley cv. Luxor in relation to short and long term periods of cold followed by a brief frost treatment were studied in order to disclose proteins responsible for the cold hardening process in distinct plant tissues. The mentioned changes have been monitored using two dimensional difference gel electrophoresis (2D-DIGE) with subsequent peptide-mapping protein identification. Regarding approximately 600–700 distinct protein spots detected on 2D gels, there has been found at least a two-fold change after exposure to low temperatures in about 10% of proteins in leaves and 13% of proteins in crowns. Protein and nitrogen metabolic processes have been influenced by low temperature to a similar extent in both tissues while catabolism, carbohydrate metabolism and proteins involved in stress response have been more affected in crowns than in leaves. The range of changes in protein abundance was generally higher in leaves and chloroplast proteins were frequently affected which suggests a priority to protect photosynthetic apparatus. Overall, our data proved existence of slightly different response strategies to low temperature stress in crowns and leaves, i.e., tissues with different biological role. Moreover, there have been found several proteins with large increase in accumulation, e.g., 33 kDa oxygen evolving protein of photosystem II in leaves and “enhanced disease susceptibility 1” in crowns; these proteins might have potential to indicate an enhanced level of frost tolerance in barley. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Environmental Stresses Induce Misfolded Protein Aggregation in Plant Cells in a Microtubule-Dependent Manner
Int. J. Mol. Sci. 2013, 14(4), 7771-7783; doi:10.3390/ijms14047771
Received: 28 January 2013 / Revised: 25 March 2013 / Accepted: 27 March 2013 / Published: 10 April 2013
Cited by 11 | PDF Full-text (4368 KB) | HTML Full-text | XML Full-text
Abstract
Misfolded protein aggregation in mammalian cells is one of the cellular responses to environmental stresses. However, the aggregation of misfolded proteins in plant cells exposed to environmental stresses is still poorly understood. Here, we report the misfolded protein aggregation in plant cells in
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Misfolded protein aggregation in mammalian cells is one of the cellular responses to environmental stresses. However, the aggregation of misfolded proteins in plant cells exposed to environmental stresses is still poorly understood. Here, we report the misfolded protein aggregation in plant cells in response to environmental stresses, including ultraviolet (UV) radiation, heat stress and cold stress. Treatment of grape and tobacco cultured cells with MG-132, a proteasome inhibitor, induced misfolded protein aggregation. All of the environmental stresses examined induced the endoplasmic reticulum (ER) stress response in the cells. The cells under ER stress showed aggregation of misfolded proteins. The misfolded protein aggregation was completely inhibited by treatment of the cells with trichostatin A or colchicine, suggesting that the misfolded proteins might be aggregated in plant cells in a microtubule-dependent manner. Detected aggregates were initially observed immediately after exposure to the environmental stresses (1 min after UV radiation, 5 min after heat stress exposure, and 15 min after cold stress exposure). Based on these findings, we hypothesize that environmental stresses induce misfolded protein aggregation in plant cells in a microtubule-dependent manner. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessArticle Plant Core Environmental Stress Response Genes Are Systemically Coordinated during Abiotic Stresses
Int. J. Mol. Sci. 2013, 14(4), 7617-7641; doi:10.3390/ijms14047617
Received: 1 February 2013 / Revised: 28 March 2013 / Accepted: 29 March 2013 / Published: 8 April 2013
Cited by 10 | PDF Full-text (2031 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Studying plant stress responses is an important issue in a world threatened by global warming. Unfortunately, comparative analyses are hampered by varying experimental setups. In contrast, the AtGenExpress abiotic stress experiment displays intercomparability. Importantly, six of the nine stresses (wounding, genotoxic, oxidative, UV-B
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Studying plant stress responses is an important issue in a world threatened by global warming. Unfortunately, comparative analyses are hampered by varying experimental setups. In contrast, the AtGenExpress abiotic stress experiment displays intercomparability. Importantly, six of the nine stresses (wounding, genotoxic, oxidative, UV-B light, osmotic and salt) can be examined for their capacity to generate systemic signals between the shoot and root, which might be essential to regain homeostasis in Arabidopsis thaliana. We classified the systemic responses into two groups: genes that are regulated in the non-treated tissue only are defined as type I responsive and, accordingly, genes that react in both tissues are termed type II responsive. Analysis of type I and II systemic responses suggest distinct functionalities, but also significant overlap between different stresses. Comparison with salicylic acid (SA) and methyl-jasmonate (MeJA) responsive genes implies that MeJA is involved in the systemic stress response. Certain genes are predominantly responding in only one of the categories, e.g., WRKY genes respond mainly non-systemically. Instead, genes of the plant core environmental stress response (PCESR), e.g., ZAT10, ZAT12, ERD9 or MES9, are part of different response types. Moreover, several PCESR genes switch between the categories in a stress-specific manner. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Transcriptional Analysis of Drought-Induced Genes in the Roots of a Tolerant Genotype of the Common Bean (Phaseolus vulgaris L.)
Int. J. Mol. Sci. 2013, 14(4), 7155-7179; doi:10.3390/ijms14047155
Received: 1 January 2013 / Revised: 6 March 2013 / Accepted: 7 March 2013 / Published: 28 March 2013
Cited by 11 | PDF Full-text (889 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In Brazil, common bean (Phaseolus vulgaris L.) productivity is severely affected by drought stress due to low technology cultivation systems. Our purpose was to identify differentially expressed genes in roots of a genotype tolerant to water deficit (BAT 477) when submitted to
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In Brazil, common bean (Phaseolus vulgaris L.) productivity is severely affected by drought stress due to low technology cultivation systems. Our purpose was to identify differentially expressed genes in roots of a genotype tolerant to water deficit (BAT 477) when submitted to an interruption of irrigation during its development. A SSH library was constructed taking as “driver” the genotype Carioca 80SH (susceptible to drought). After clustering and data mining, 1572 valid reads were obtained, resulting in 1120 ESTs (expressed sequence tags). We found sequences for transcription factors, carbohydrates metabolism, proline-rich proteins, aquaporins, chaperones and ubiquitins, all of them organized according to their biological processes. Our suppressive subtractive hybridization (SSH) library was validated through RT-qPCR experiment by assessing the expression patterns of 10 selected genes in both genotypes under stressed and control conditions. Finally, the expression patterns of 31 ESTs, putatively related to drought responses, were analyzed in a time-course experiment. Our results confirmed that such genes are more expressed in the tolerant genotype during stress; however, they are not exclusive, since different levels of these transcripts were also detected in the susceptible genotype. In addition, we observed a fluctuation in gene regulation over time for both the genotypes, which seem to adopt and adapt different strategies in order to develop tolerance against this stress. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Cadmium Tolerance and Removal from Cunninghamella elegans Related to the Polyphosphate Metabolism
Int. J. Mol. Sci. 2013, 14(4), 7180-7192; doi:10.3390/ijms14047180
Received: 3 February 2013 / Revised: 12 March 2013 / Accepted: 18 March 2013 / Published: 28 March 2013
Cited by 7 | PDF Full-text (483 KB) | HTML Full-text | XML Full-text
Abstract
The aim of the present work was to study the cadmium effects on growth, ultrastructure and polyphosphate metabolism, as well as to evaluate the metal removal and accumulation by Cunninghamella elegans (IFM 46109) growing in culture medium. The presence of cadmium reduced growth,
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The aim of the present work was to study the cadmium effects on growth, ultrastructure and polyphosphate metabolism, as well as to evaluate the metal removal and accumulation by Cunninghamella elegans (IFM 46109) growing in culture medium. The presence of cadmium reduced growth, and a longer lag phase was observed. However, the phosphate uptake from the culture medium increased 15% when compared to the control. Moreover, C. elegans removed 70%–81% of the cadmium added to the culture medium during its growth. The C. elegans mycelia showed a removal efficiency of 280 mg/g at a cadmium concentration of 22.10 mg/L, and the removal velocity of cadmium was 0.107 mg/h. Additionally, it was observed that cadmium induced vacuolization, the presence of electron dense deposits in vacuoles, cytoplasm and cell membranes, as well as the distinct behavior of polyphosphate fractions. The results obtained with C. elegans suggest that precipitation, vacuolization and polyphosphate fractions were associated to cadmium tolerance, and this species demonstrated a higher potential for bioremediation of heavy metals. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Disruption of AtWNK8 Enhances Tolerance of Arabidopsis to Salt and Osmotic Stresses via Modulating Proline Content and Activities of Catalase and Peroxidase
Int. J. Mol. Sci. 2013, 14(4), 7032-7047; doi:10.3390/ijms14047032
Received: 13 December 2012 / Revised: 4 March 2013 / Accepted: 7 March 2013 / Published: 27 March 2013
Cited by 12 | PDF Full-text (2012 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
With no lysine kinases (WNKs) play important roles in plant growth and development. However, its role in salt and osmotic stress tolerance is unclear. Here, we report that AtWNK8 is mainly expressed in primary root, hypocotyl, stamen and pistil and is induced by
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With no lysine kinases (WNKs) play important roles in plant growth and development. However, its role in salt and osmotic stress tolerance is unclear. Here, we report that AtWNK8 is mainly expressed in primary root, hypocotyl, stamen and pistil and is induced by NaCl and sorbitol treatment. Compared to the wild-type, the T-DNA knock-out wnk8 mutant was more tolerant to severe salinity and osmotic stresses, as indicated by 27% and 198% more fresh weight in the NaCl and sorbitol treatment, respectively. The wnk8 mutant also accumulated 1.43-fold more proline than the wild-type in the sorbitol treatment. Under NaCl and sorbitol stresses, catalase (CAT) activity in wnk8 mutant was 1.92- and 3.7-times of that in Col-0, respectively. Similarly, under salt and osmotic stress conditions, peroxidase (POD) activities in wnk8 mutant were 1.81- and 1.58-times of that in Col-0, respectively. Taken together, we revealed that maintaining higher CAT and POD activities might be one of the reasons that the disruption of AtWNK8 enhances the tolerance to salt stress, and accumulating more proline and higher activities of CAT and POD might result in the higher tolerance of WNK8 to osmotic stress. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Transgenerational, Dynamic Methylation of Stomata Genes in Response to Low Relative Humidity
Int. J. Mol. Sci. 2013, 14(4), 6674-6689; doi:10.3390/ijms14046674
Received: 31 January 2013 / Revised: 9 March 2013 / Accepted: 18 March 2013 / Published: 26 March 2013
Cited by 14 | PDF Full-text (481 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Transgenerational inheritance of abiotic stress-induced epigenetic modifications in plants has potential adaptive significance and might condition the offspring to improve the response to the same stress, but this is at least partly dependent on the potency, penetrance and persistence of the transmitted epigenetic
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Transgenerational inheritance of abiotic stress-induced epigenetic modifications in plants has potential adaptive significance and might condition the offspring to improve the response to the same stress, but this is at least partly dependent on the potency, penetrance and persistence of the transmitted epigenetic marks. We examined transgenerational inheritance of low Relative Humidity-induced DNA methylation for two gene loci in the stomatal developmental pathway in Arabidopsis thaliana and the abundance of associated short-interfering RNAs (siRNAs). Heritability of low humidity-induced methylation was more predictable and penetrative at one locus (SPEECHLESS, entropy ≤ 0.02; χ2 < 0.001) than the other (FAMA, entropy ≤ 0.17; χ2 ns). Methylation at SPEECHLESS correlated positively with the continued presence of local siRNAs (r2 = 0.87; p = 0.013) which, however, could be disrupted globally in the progeny under repeated stress. Transgenerational methylation and a parental low humidity-induced stomatal phenotype were heritable, but this was reversed in the progeny under repeated treatment in a previously unsuspected manner. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Identification of Amplified Fragment Length Polymorphism (AFLP) Markers Tightly Associated with Drought Stress Gene in Male Sterile and Fertile Salvia miltiorrhiza Bunge
Int. J. Mol. Sci. 2013, 14(3), 6518-6528; doi:10.3390/ijms14036518
Received: 28 January 2013 / Revised: 22 February 2013 / Accepted: 25 February 2013 / Published: 22 March 2013
Cited by 1 | PDF Full-text (1133 KB) | HTML Full-text | XML Full-text
Abstract
Consistent grain yield in drought environment has attracted wide attention due to global climate change. However, the important drought-related traits/genes in crops have been rarely reported. Many near-isogenic lines (NILs) of male sterile and fertile Salvia miltiorrhiza have been obtained in our previous
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Consistent grain yield in drought environment has attracted wide attention due to global climate change. However, the important drought-related traits/genes in crops have been rarely reported. Many near-isogenic lines (NILs) of male sterile and fertile Salvia miltiorrhiza have been obtained in our previous work through testcross and backcross in continuous field experiments conducted in 2006–2009. Both segregating sterile and fertile populations were subjected to bulked segregant analysis (BSA) and amplified fragment length polymorphism (AFLP) with 384 and 170 primer combinations, respectively. One out of 14 AFLP markers (E9/M3246) was identified in treated fertile population as tightly linked to the drought stress gene with a recombination frequency of 6.98% and at a distance of 7.02 cM. One of 15 other markers (E2/M5357) was identified in a treated sterile population that is closely associated with the drought stress gene. It had a recombination frequency of 4.65% and at a distance of 4.66 cM. Interestingly, the E9/M3246 fragment was found to be identical to another AFLP fragment E11/M4208 that was tightly linked to the male sterile gene of S. miltiorrhiza with 95% identity and e-value 4 × 10−93. Blastn analysis suggested that the drought stress gene sequence showed higher identity with nucleotides in Arabidopsis chromosome 1–5. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle A Rice Immunophilin Gene, OsFKBP16-3, Confers Tolerance to Environmental Stress in Arabidopsis and Rice
Int. J. Mol. Sci. 2013, 14(3), 5899-5919; doi:10.3390/ijms14035899
Received: 30 January 2013 / Revised: 4 March 2013 / Accepted: 5 March 2013 / Published: 13 March 2013
Cited by 6 | PDF Full-text (2060 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The putative thylakoid lumen immunophilin, FKBP16-3, has not yet been characterized, although this protein is known to be regulated by thioredoxin and possesses a well-conserved CxxxC motif in photosynthetic organisms. Here, we characterized rice OsFKBP16-3 and examined the role of this gene in
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The putative thylakoid lumen immunophilin, FKBP16-3, has not yet been characterized, although this protein is known to be regulated by thioredoxin and possesses a well-conserved CxxxC motif in photosynthetic organisms. Here, we characterized rice OsFKBP16-3 and examined the role of this gene in the regulation of abiotic stress in plants. FKBP16-3s are well conserved in eukaryotic photosynthetic organisms, including the presence of a unique disulfide-forming CxxxC motif in their N-terminal regions. OsFKBP16-3 was mainly expressed in rice leaf tissues and was upregulated by various abiotic stresses, including salt, drought, high light, hydrogen peroxide, heat and methyl viologen. The chloroplast localization of OsFKBP16-3-GFP was confirmed through the transient expression of OsFKBP16-3 in Nicotiana benthamiana leaves. Transgenic Arabidopsis and transgenic rice plants that constitutively expressed OsFKBP16-3 exhibited increased tolerance to salinity, drought and oxidative stresses, but showed no change in growth or phenotype, compared with vector control plants, when grown under non-stressed conditions. This is the first report to demonstrate the potential role of FKBP16-3 in the environmental stress response, which may be regulated by a redox relay process in the thylakoid lumen, suggesting that artificial regulation of FKBP16-3 expression is a candidate for stress-tolerant crop breeding. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Water Deficit and Heat Affect the Tolerance to High Illumination in Hibiscus Plants
Int. J. Mol. Sci. 2013, 14(3), 5432-5444; doi:10.3390/ijms14035432
Received: 22 January 2013 / Revised: 1 March 2013 / Accepted: 4 March 2013 / Published: 7 March 2013
Cited by 8 | PDF Full-text (387 KB) | HTML Full-text | XML Full-text
Abstract
This work studies the effects of water deficit and heat, as well as the involvement of chlororespiration and the ferredoxin-mediated cyclic pathway, on the tolerance of photosynthesis to high light intensity in Hibiscus rosa-sinensis plants. Drought and heat resulted in the down–regulation of
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This work studies the effects of water deficit and heat, as well as the involvement of chlororespiration and the ferredoxin-mediated cyclic pathway, on the tolerance of photosynthesis to high light intensity in Hibiscus rosa-sinensis plants. Drought and heat resulted in the down–regulation of photosynthetic linear electron transport in the leaves, although only a slight decrease in variable fluorescence (Fv)/maximal fluorescence (Fm) was observed, indicating that the chloroplast was protected by mechanisms that dissipate excess excitation energy to prevent damage to the photosynthetic apparatus. The incubation of leaves from unstressed plants under high light intensity resulted in an increase of the activity of electron donation by nicotinamide adenine dinucleotide phosphate (NADPH) and ferredoxin to plastoquinone, but no increase was observed in plants exposed to water deficit, suggesting that cyclic electron transport was stimulated by high light only in control plants. In contrast, the activities of the chlororespiration enzymes (NADH dehydrogenase (NDH) complex and plastid terminal oxidase (PTOX)) increased after incubation under high light intensity in leaves of the water deficit plants, but not in control plants, suggesting that chlororespiration was stimulated in stressed plants. The results indicate that the relative importance of chlororespiration and the cyclic electron pathway in the tolerance of photosynthesis to high illumination differs under stress conditions. When plants were not subjected to stress, the contribution of chlororespiration to photosynthetic electron flow regulation was not relevant, and another pathway, such as the ferredoxin-mediated cyclic pathway, was more important. However, when plants were subjected to water deficit and heat, chlororespiration was probably essential. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Comparative Analysis of the Symbiotic Efficiency of Medicago truncatula and Medicago sativa under Phosphorus Deficiency
Int. J. Mol. Sci. 2013, 14(3), 5198-5213; doi:10.3390/ijms14035198
Received: 28 January 2013 / Revised: 14 February 2013 / Accepted: 26 February 2013 / Published: 4 March 2013
Cited by 9 | PDF Full-text (238 KB) | HTML Full-text | XML Full-text
Abstract
Phosphorus (P)-deficiency is a major abiotic stress that limits legume growth in many types of soils. The relationship between Medicago and Sinorhizobium, is known to be affected by different environmental conditions. Recent reports have shown that, in combination with S. meliloti 2011, Medicago
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Phosphorus (P)-deficiency is a major abiotic stress that limits legume growth in many types of soils. The relationship between Medicago and Sinorhizobium, is known to be affected by different environmental conditions. Recent reports have shown that, in combination with S. meliloti 2011, Medicago truncatula had a lower symbiotic efficiency than Medicago sativa. However, little is known about how Medicago–Sinorhizobium is affected by P-deficiency at the whole-plant level. The objective of the present study was to compare and characterize the symbiotic efficiency of N2 fixation of M. truncatula and M. sativa grown in sand under P-limitation. Under this condition, M. truncatula exhibited a significantly higher rate of N2 fixation. The specific activity of the nodules was much higher in M. truncatula in comparison to M. sativa, partially as a result of an increase in electron allocation to N2 versus H+. Although the main organic acid, succinate, exhibited a strong tendency to decrease under P-deficiency, the more efficient symbiotic ability observed in M. truncatula coincided with an apparent increase in the content of malate in its nodules. Our results indicate that the higher efficiency of the M. truncatula symbiotic system is related to the ability to increase malate content under limited P-conditions. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Insight into Differential Responses of Upland and Paddy Rice to Drought Stress by Comparative Expression Profiling Analysis
Int. J. Mol. Sci. 2013, 14(3), 5214-5238; doi:10.3390/ijms14035214
Received: 9 January 2013 / Revised: 30 January 2013 / Accepted: 5 February 2013 / Published: 4 March 2013
Cited by 9 | PDF Full-text (1103 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In this study, the drought responses of two genotypes, IRAT109 and Zhenshan 97 (ZS97), representing upland and paddy rice, respectively, were systematically compared at the morphological, physiological and transcriptional levels. IRAT109 has better performance in traits related to drought avoidance, such as leaf
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In this study, the drought responses of two genotypes, IRAT109 and Zhenshan 97 (ZS97), representing upland and paddy rice, respectively, were systematically compared at the morphological, physiological and transcriptional levels. IRAT109 has better performance in traits related to drought avoidance, such as leaf rolling, root volumes, the ratio of leaf water loss and relative conductivity. At the transcriptional level, more genes were induced by drought in IRAT109 at the early drought stage, but more genes had dynamic expression patterns in ZS97 at different drought degrees. Under drought conditions, more genes related to reproductive development and establishment of localization were repressed in IRAT109, but more genes involved in degradation of cellular components were induced in ZS97. By checking the expression patterns of 36 drought-responsive genes (located in 14 quantitative trail loci [QTL] intervals) in ZS97, IRAT109 and near isogenic lines (NILs) of the QTL intervals, we found that more than half of these genes had their expression patterns or expression levels changed in the NILs when compared to that in ZS97 or IRAT109. Our results may provide valuable information for dissecting the genetic bases of traits related to drought resistance, as well as for narrowing the candidate genes for the traits. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Differential Protein Expression in Response to Abiotic Stress in Two Potato Species: Solanum commersonii Dun and Solanum tuberosum L.
Int. J. Mol. Sci. 2013, 14(3), 4912-4933; doi:10.3390/ijms14034912
Received: 22 December 2012 / Revised: 8 February 2013 / Accepted: 13 February 2013 / Published: 1 March 2013
Cited by 12 | PDF Full-text (354 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Better knowledge on responses to dehydration stress could help to improve the existing cryopreservation protocols for potato, since plant tissues processed for cryopreservation are often submitted to similar in vitro stress conditions. Cryopreservation (the best method of conservation for vegetatively propagated plants) of
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Better knowledge on responses to dehydration stress could help to improve the existing cryopreservation protocols for potato, since plant tissues processed for cryopreservation are often submitted to similar in vitro stress conditions. Cryopreservation (the best method of conservation for vegetatively propagated plants) of potato still needs to be standardized to make it available and to conserve the wide diversity of this crop. In the present work, the response to osmotic stress and chilling temperature was investigated in two potato species, Solanum tuberosum and its relative, frost-tolerant S. commersonii. After 14 days of exposure, different growth parameters, such as shoot length and number of leaves, were measured. Furthermore, differentially abundant proteins were identified after performing 2-fluorescence difference gel electrophoresis (2-DIGE) experiments, and soluble carbohydrates were analyzed by High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). The results show different responses in both species depending on the stress treatment. Focusing on the differences in growth parameters during the treatments, Solanum commersonii seems to be more affected than S. tuberosum cv. Désirée. At the molecular level, there are some differences and similarities between the two potato species studied that are dependent on the type of stressor. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Secretory Phospholipases A2 in Durum Wheat (Triticum durum Desf.): Gene Expression, Enzymatic Activity, and Relation to Drought Stress Adaptation
Int. J. Mol. Sci. 2013, 14(3), 5146-5169; doi:10.3390/ijms14035146
Received: 18 January 2013 / Revised: 13 February 2013 / Accepted: 18 February 2013 / Published: 1 March 2013
Cited by 11 | PDF Full-text (1401 KB) | HTML Full-text | XML Full-text
Abstract
Phospholipases A2 (PLA2s) are known to mediate signaling cascades during plant growth and development, as well as biotic and abiotic stress responses. In this context, the present study provides extensive characterization of specific PLA2s in durum wheat, and
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Phospholipases A2 (PLA2s) are known to mediate signaling cascades during plant growth and development, as well as biotic and abiotic stress responses. In this context, the present study provides extensive characterization of specific PLA2s in durum wheat, and assesses their involvement in durum wheat response to drought stress. In durum wheat leaves, four full-length expressed sequences encoding putative PLA2s were isolated and characterized as belonging to the class of secretory PLA2s (sPLA2s): TdsPLA2I, TdsPLA2II, TdsPLA2III and TdsPLA2IV. PLA2 activity was also detected, the characteristics of which resemble those of previously characterized plant sPLA2s: strong preference for phospholipids; requirement for millimolar Ca2+ concentrations; optimal activity at basic pH; heat stability; and inhibition by the reducing agent dithiothreitol. With drought stress imposed at both the vegetative and reproductive stages, accumulation of TdsPLA2I and TdsPLA2III transcripts, and to a lesser extent of TdsPLA2IV transcript, paralleled increased PLA2 activity; both transcript levels and enzymatic activity decreased as a consequence of stress recovery. Consistently, free fatty acid analysis of drought-stressed leaves revealed increased linoleate, linolenate and palmitate contents, which were reversed by plant re-watering. Overall, these findings strongly suggest that there are inducible sPLA2 isoforms in durum wheat that have roles in orchestrating the plant response to drought stress. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessArticle Proteome Analysis of Rice (Oryza sativa L.) Mutants Reveals Differentially Induced Proteins during Brown Planthopper (Nilaparvata lugens) Infestation
Int. J. Mol. Sci. 2013, 14(2), 3921-3945; doi:10.3390/ijms14023921
Received: 17 September 2012 / Revised: 20 January 2013 / Accepted: 22 January 2013 / Published: 15 February 2013
Cited by 10 | PDF Full-text (4056 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Although rice resistance plays an important role in controlling the brown planthopper (BPH), Nilaparvata lugens, not all varieties have the same level of protection against BPH infestation. Understanding the molecular interactions in rice defense response is an important tool to help to
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Although rice resistance plays an important role in controlling the brown planthopper (BPH), Nilaparvata lugens, not all varieties have the same level of protection against BPH infestation. Understanding the molecular interactions in rice defense response is an important tool to help to reveal unexplained processes that underlie rice resistance to BPH. A proteomics approach was used to explore how wild type IR64 and near-isogenic rice mutants with gain and loss of resistance to BPH respond during infestation. A total of 65 proteins were found markedly altered in wild type IR64 during BPH infestation. Fifty-two proteins associated with 11 functional categories were identified using mass spectrometry. Protein abundance was less altered at 2 and 14 days after infestation (DAI) (T1, T2, respectively), whereas higher protein levels were observed at 28 DAI (T3). This trend diminished at 34 DAI (T4). Comparative analysis of IR64 with mutants showed 22 proteins that may be potentially associated with rice resistance to the brown planthopper (BPH). Ten proteins were altered in susceptible mutant (D1131) whereas abundance of 12 proteins including S-like RNase, Glyoxalase I, EFTu1 and Salt stress root protein “RS1” was differentially changed in resistant mutant (D518). S-like RNase was found in greater quantities in D518 after BPH infestation but remained unchanged in IR64 and decreased in D1131. Taken together, this study shows a noticeable level of protein abundance in the resistant mutant D518 compared to the susceptible mutant D1131 that may be involved in rendering enhanced level of resistance against BPH. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle A Novel Peroxidase CanPOD Gene of Pepper Is Involved in Defense Responses to Phytophtora capsici Infection as well as Abiotic Stress Tolerance
Int. J. Mol. Sci. 2013, 14(2), 3158-3177; doi:10.3390/ijms14023158
Received: 15 January 2013 / Revised: 30 January 2013 / Accepted: 30 January 2013 / Published: 4 February 2013
Cited by 25 | PDF Full-text (944 KB) | HTML Full-text | XML Full-text
Abstract
Peroxidases are involved in many plant processes including plant defense responses to biotic and abiotic stresses. We isolated a novel peroxidase gene CanPOD from leaves of pepper cultivar A3. The full-length gene has a 1353-bp cDNA sequence and contains an open reading frame
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Peroxidases are involved in many plant processes including plant defense responses to biotic and abiotic stresses. We isolated a novel peroxidase gene CanPOD from leaves of pepper cultivar A3. The full-length gene has a 1353-bp cDNA sequence and contains an open reading frame (ORF) of 975-bp, which encodes a putative polypeptide of 324 amino acids with a theoretical protein size of 34.93 kDa. CanPOD showed diverse expression levels in different tissues of pepper plants. To evaluate the role of CanPOD in plant stress responses, the expression patterns of CanPOD were examined using Real-Time RT-PCR. The results indicated that CanPOD was significantly induced by Phytophtora capsici. Moreover, CanPOD was also up-regulated in leaves after salt and drought stress treatments. In addition, CanPOD expression was strongly induced by signaling hormones salicylic acid (SA). In contrast, CanPOD was not highly expressed after treatment with cold. Meanwhile, in order to further assess the role of gene CanPOD in defense response to P. capsici attack, we performed a loss-of-function experiment using the virus-induced gene silencing (VIGS) technique in pepper plants. In comparison to the control plant, the expression levels of CanPOD were obviously decreased in CanPOD-silenced pepper plants. Furthermore, we analyzed the effect of P. capsici on detached-leaves and found that the CanPOD-silenced plant leaves were highly susceptible to P. capsici infection. Taken together, our results suggested that CanPOD is involved in defense responses to P. capsici infection as well as abiotic stresses in pepper plants. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle The Transcriptome of Brassica napus L. Roots under Waterlogging at the Seedling Stage
Int. J. Mol. Sci. 2013, 14(2), 2637-2651; doi:10.3390/ijms14022637
Received: 27 November 2012 / Revised: 11 January 2013 / Accepted: 14 January 2013 / Published: 28 January 2013
Cited by 14 | PDF Full-text (1300 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Although rapeseed (Brassica napus L.) is known to be affected by waterlogging, the genetic basis of waterlogging tolerance by rapeseed is largely unknown. In this study, the transcriptome under 0 h and 12 h of waterlogging was assayed in the roots of
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Although rapeseed (Brassica napus L.) is known to be affected by waterlogging, the genetic basis of waterlogging tolerance by rapeseed is largely unknown. In this study, the transcriptome under 0 h and 12 h of waterlogging was assayed in the roots of ZS9, a tolerant variety, using digital gene expression (DGE). A total of 4432 differentially expressed genes were identified, indicating that the response to waterlogging in rapeseed is complicated. The assignments of the annotated genes based on GO (Gene Ontology) revealed there were more genes induced under waterlogging in “oxidation reduction”, “secondary metabolism”, “transcription regulation”, and “translation regulation”; suggesting these four pathways are enhanced under waterlogging. Analysis of the 200 most highly expressed genes illustrated that 144 under normal conditions were down-regulated by waterlogging, while up to 191 under waterlogging were those induced in response to stress. The expression of genes involved under waterlogging is mediated by multiple levels of transcriptional, post-transcriptional, translational and post-translational regulation, including phosphorylation and protein degradation; in particular, protein degradation might be involved in the negative regulation in response to this stress. Our results provide new insight into the response to waterlogging and will help to identify important candidate genes. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Mitochondrial Cytochrome c Oxidase and F1Fo-ATPase Dysfunction in Peppers (Capsicum annuum L.) with Cytoplasmic Male Sterility and Its Association with orf507 and Ψatp6-2 Genes
Int. J. Mol. Sci. 2013, 14(1), 1050-1068; doi:10.3390/ijms14011050
Received: 23 November 2012 / Revised: 13 December 2012 / Accepted: 28 December 2012 / Published: 7 January 2013
Cited by 13 | PDF Full-text (3189 KB) | HTML Full-text | XML Full-text
Abstract
Cytoplasmic male sterility (CMS) in pepper (Capsicum annuum L.) has been associated with novel genes in the mitochondria, such as orf507 and Ψatp6-2. Plant sterility has been proved to result from the rearrangement of the mitochondrial genome. Previous studies have demonstrated
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Cytoplasmic male sterility (CMS) in pepper (Capsicum annuum L.) has been associated with novel genes in the mitochondria, such as orf507 and Ψatp6-2. Plant sterility has been proved to result from the rearrangement of the mitochondrial genome. Previous studies have demonstrated that orf507 is co-transcribed with the cox II gene, and Ψatp6-2 is truncated at the 3' region of the atp6-2 that is found in the maintainer line. Until this time, little has been known about the relationship between the novel gene and the function of its corresponding enzyme in mitochondria from the CMS pepper line. Moreover, the aberrant function of the mitochondrial enzymes is seldom reported in pepper. In this study, we observed that anther abortion occurred after the tetrad stage in the CMS line (HW203A), which was accompanied by premature programmed cell death (PCD) in the tapetum. The spatiotemporal expression patterns of orf507 and Ψatp6-2 were analyzed together with the corresponding enzyme activities to investigate the interactions of the genes and mitochondrial enzymes. The two genes were both highly expressed in the anther. The orf507 was down-regulated in HW203A (CMS line), with nearly no expression in HW203B (the maintainer line). In contrast, the cytochrome c oxidase activity in HW203A showed the opposite trend, reaching its highest peak at the tetrad stage when compared with HW203B at the same stage. The Ψatp6-2 in the CMS line was also down-regulated, but it was up-regulated in the maintainer line. The corresponding F1Fo-ATPase activity in the CMS line was gradually decreased along with the development of the anther, which showed the same trend for Ψatp6-2 gene expression. On the contrary, with up-regulated gene expression of atp6-2 in the maintainer line, the F1Fo-ATPase activity sharply decreased after the initial development stage, but gradually increased following the tetrad stage, which was contrary to what happened in the CMS line. Taken together, all these results may provide evidence for the involvement of aberrant mitochondrial cytochrome c oxidase and F1Fo-ATPase in CMS pepper anther abortion. Moreover, the novel orf507 and Ψatp6-2 genes in the mitochondria may be involved in the dysfunction of the cytochrome c oxidase and F1Fo-ATPase, respectively, which are responsible for the abortion of anthers in the CMS line. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle The Voltage-Dependent Anion Channel 1 (AtVDAC1) Negatively Regulates Plant Cold Responses during Germination and Seedling Development in Arabidopsis and Interacts with Calcium Sensor CBL1
Int. J. Mol. Sci. 2013, 14(1), 701-713; doi:10.3390/ijms14010701
Received: 26 October 2012 / Revised: 12 December 2012 / Accepted: 12 December 2012 / Published: 4 January 2013
Cited by 7 | PDF Full-text (676 KB) | HTML Full-text | XML Full-text
Abstract
The voltage-dependent anion channel (VDAC), a highly conserved major mitochondrial outer membrane protein, plays crucial roles in energy metabolism and metabolite transport. However, knowledge about the roles of the VDAC family in plants is limited. In this study, we investigated the expression pattern
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The voltage-dependent anion channel (VDAC), a highly conserved major mitochondrial outer membrane protein, plays crucial roles in energy metabolism and metabolite transport. However, knowledge about the roles of the VDAC family in plants is limited. In this study, we investigated the expression pattern of VDAC1 in Arabidopsis and found that cold stress promoted the accumulation of VDAC1 transcripts in imbibed seeds and mature plants. Overexpression of VDAC1 reduced tolerance to cold stress in Arabidopsis. Phenotype analysis of VDAC1 T-DNA insertion mutant plants indicated that a vdac1 mutant line had faster germination kinetics under cold treatment and showed enhanced tolerance to freezing. The yeast two-hybrid system revealed that VDAC1 interacts with CBL1, a calcium sensor in plants. Like the vdac1, a cbl1 mutant also exhibited a higher seed germination rate. We conclude that both VDAC1 and CBL1 regulate cold stress responses during seed germination and plant development. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessArticle Wheat Drought-Responsive Grain Proteome Analysis by Linear and Nonlinear 2-DE and MALDI-TOF Mass Spectrometry
Int. J. Mol. Sci. 2012, 13(12), 16065-16083; doi:10.3390/ijms131216065
Received: 15 October 2012 / Revised: 13 November 2012 / Accepted: 14 November 2012 / Published: 29 November 2012
Cited by 23 | PDF Full-text (542 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A comparative proteomic analysis of drought-responsive proteins during grain development of two wheat varieties Kauz (strong resistance to drought stress) and Janz (sensitive to drought stress) was performed by using linear and nonlinear 2-DE and MALDI-TOF mass spectrometry technologies. Results revealed that the
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A comparative proteomic analysis of drought-responsive proteins during grain development of two wheat varieties Kauz (strong resistance to drought stress) and Janz (sensitive to drought stress) was performed by using linear and nonlinear 2-DE and MALDI-TOF mass spectrometry technologies. Results revealed that the nonlinear 2-DE had much higher resolution than the linear 2-DE. A total of 153 differentially expressed protein spots were detected by both 2-DE maps, of which 122 protein spots were identified by MALDI-TOF and MALDI-TOF/TOF mass spectrometry. The identified differential proteins were mainly involved in carbohydrate metabolism (26%), detoxification and defense (23%), and storage proteins (17%). Some key proteins demonstrated significantly different expression patterns between the two varieties. In particular, catalase isozyme 1, WD40 repeat protein, LEA and alpha-amylase inhibitors displayed an upregulated expression pattern in Kauz, whereas they were downregulated or unchanged in Janz. Small and large subunit ADP glucose pyrophosphorylase, ascorbate peroxidase and G beta-like protein were all downregulated under drought stress in Janz, but had no expression changes in Kauz. Sucrose synthase and triticin precursor showed an upregulated expression pattern under water deficits in both varieties, but their upregulation levels were much higher in Kauz than in Janz. These differentially expressed proteins could be related to the biochemical pathways for stronger drought resistance of Kauz. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)

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Open AccessReview Silicon Era of Carbon-Based Life: Application of Genomics and Bioinformatics in Crop Stress Research
Int. J. Mol. Sci. 2013, 14(6), 11444-11483; doi:10.3390/ijms140611444
Received: 31 January 2013 / Revised: 7 May 2013 / Accepted: 17 May 2013 / Published: 29 May 2013
Cited by 3 | PDF Full-text (725 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Abiotic and biotic stresses lead to massive reprogramming of different life processes and are the major limiting factors hampering crop productivity. Omics-based research platforms allow for a holistic and comprehensive survey on crop stress responses and hence may bring forth better crop improvement
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Abiotic and biotic stresses lead to massive reprogramming of different life processes and are the major limiting factors hampering crop productivity. Omics-based research platforms allow for a holistic and comprehensive survey on crop stress responses and hence may bring forth better crop improvement strategies. Since high-throughput approaches generate considerable amounts of data, bioinformatics tools will play an essential role in storing, retrieving, sharing, processing, and analyzing them. Genomic and functional genomic studies in crops still lag far behind similar studies in humans and other animals. In this review, we summarize some useful genomics and bioinformatics resources available to crop scientists. In addition, we also discuss the major challenges and advancements in the “-omics” studies, with an emphasis on their possible impacts on crop stress research and crop improvement. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Physiological, Biochemical, and Molecular Mechanisms of Heat Stress Tolerance in Plants
Int. J. Mol. Sci. 2013, 14(5), 9643-9684; doi:10.3390/ijms14059643
Received: 1 February 2013 / Revised: 16 April 2013 / Accepted: 19 April 2013 / Published: 3 May 2013
Cited by 108 | PDF Full-text (1649 KB) | HTML Full-text | XML Full-text
Abstract
High temperature (HT) stress is a major environmental stress that limits plant growth, metabolism, and productivity worldwide. Plant growth and development involve numerous biochemical reactions that are sensitive to temperature. Plant responses to HT vary with the degree and duration of HT and
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High temperature (HT) stress is a major environmental stress that limits plant growth, metabolism, and productivity worldwide. Plant growth and development involve numerous biochemical reactions that are sensitive to temperature. Plant responses to HT vary with the degree and duration of HT and the plant type. HT is now a major concern for crop production and approaches for sustaining high yields of crop plants under HT stress are important agricultural goals. Plants possess a number of adaptive, avoidance, or acclimation mechanisms to cope with HT situations. In addition, major tolerance mechanisms that employ ion transporters, proteins, osmoprotectants, antioxidants, and other factors involved in signaling cascades and transcriptional control are activated to offset stress-induced biochemical and physiological alterations. Plant survival under HT stress depends on the ability to perceive the HT stimulus, generate and transmit the signal, and initiate appropriate physiological and biochemical changes. HT-induced gene expression and metabolite synthesis also substantially improve tolerance. The physiological and biochemical responses to heat stress are active research areas, and the molecular approaches are being adopted for developing HT tolerance in plants. This article reviews the recent findings on responses, adaptation, and tolerance to HT at the cellular, organellar, and whole plant levels and describes various approaches being taken to enhance thermotolerance in plants. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessReview Endoplasmic Reticulum (ER) Stress Response and Its Physiological Roles in Plants
Int. J. Mol. Sci. 2013, 14(4), 8188-8212; doi:10.3390/ijms14048188
Received: 16 February 2013 / Revised: 19 March 2013 / Accepted: 1 April 2013 / Published: 15 April 2013
Cited by 20 | PDF Full-text (859 KB) | HTML Full-text | XML Full-text
Abstract
The endoplasmic reticulum (ER) stress response is a highly conserved mechanism that results from the accumulation of unfolded or misfolded proteins in the ER. The response plays an important role in allowing plants to sense and respond to adverse environmental conditions, such as
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The endoplasmic reticulum (ER) stress response is a highly conserved mechanism that results from the accumulation of unfolded or misfolded proteins in the ER. The response plays an important role in allowing plants to sense and respond to adverse environmental conditions, such as heat stress, salt stress and pathogen infection. Since the ER is a well-controlled microenvironment for proper protein synthesis and folding, it is highly susceptible to stress conditions. Accumulation of unfolded or misfolded proteins activates a signaling pathway, called the unfolded protein response (UPR), which acts to relieve ER stress and, if unsuccessful, leads to cell death. Plants have two arms of the UPR signaling pathway, an arm involving the proteolytic processing of membrane-associated basic leucine zipper domain (bZIP) transcription factors and an arm involving RNA splicing factor, IRE1, and its mRNA target. These signaling pathways play an important role in determining the cell’s fate in response to stress conditions. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessReview Role of Homeodomain Leucine Zipper (HD-Zip) IV Transcription Factors in Plant Development and Plant Protection from Deleterious Environmental Factors
Int. J. Mol. Sci. 2013, 14(4), 8122-8147; doi:10.3390/ijms14048122
Received: 31 January 2013 / Revised: 26 March 2013 / Accepted: 3 April 2013 / Published: 12 April 2013
Cited by 14 | PDF Full-text (589 KB) | HTML Full-text | XML Full-text
Abstract
Homeobox genes comprise an important group of genes that are responsible for regulation of developmental processes. These genes determine cell differentiation and cell fate in all eukaryotic organisms, starting from the early stages of embryo development. Homeodomain leucine zipper (HD-Zip) transcription factors are
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Homeobox genes comprise an important group of genes that are responsible for regulation of developmental processes. These genes determine cell differentiation and cell fate in all eukaryotic organisms, starting from the early stages of embryo development. Homeodomain leucine zipper (HD-Zip) transcription factors are unique to the plant kingdom. Members of the HD-Zip IV subfamily have a complex domain topology and can bind several cis-elements with overlapping sequences. Many of the reported HD-Zip IV genes were shown to be specifically or preferentially expressed in plant epidermal or sub-epidermal cells. HD-Zip IV TFs were found to be associated with differentiation and maintenance of outer cell layers, and regulation of lipid biosynthesis and transport. Insights about the role of these proteins in plant cuticle formation, and hence their possible involvement in plant protection from pathogens and abiotic stresses has just started to emerge. These roles make HD-Zip IV proteins an attractive tool for genetic engineering of crop plants. To this end, there is a need for in-depth studies to further clarify the function of each HD-Zip IV subfamily member in commercially important plant species. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Plant bZIP Transcription Factors Responsive to Pathogens: A Review
Int. J. Mol. Sci. 2013, 14(4), 7815-7828; doi:10.3390/ijms14047815
Received: 2 February 2013 / Revised: 2 April 2013 / Accepted: 2 April 2013 / Published: 10 April 2013
Cited by 42 | PDF Full-text (579 KB) | HTML Full-text | XML Full-text
Abstract
Transcription factors of the basic leucine zipper (bZIP) family control important processes in all eukaryotes. In plants, bZIPs are master regulators of many central developmental and physiological processes, including morphogenesis, seed formation, abiotic and biotic stress responses. Modulation of the expression patterns of
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Transcription factors of the basic leucine zipper (bZIP) family control important processes in all eukaryotes. In plants, bZIPs are master regulators of many central developmental and physiological processes, including morphogenesis, seed formation, abiotic and biotic stress responses. Modulation of the expression patterns of bZIP genes and changes in their activity often contribute to the activation of various signaling pathways and regulatory networks of different physiological processes. However, most advances in the study of plant bZIP transcription factors are related to their involvement in abiotic stress and development. In contrast, there are few examples of functional research with regard to biotic stress, particularly in the defense against pathogens. In this review, we summarize the recent progress revealing the role of bZIP transcription factors in the biotic stress responses of several plant species, from Arabidopsis to cotton. Moreover, we summarize the interacting partners of bZIP proteins in molecular responses during pathogen attack and the key components of the signal transduction pathways with which they physically interact during plant defense responses. Lastly, we focus on the recent advances regarding research on the functional role of bZIPs in major agricultural cultivars and examine the studies performed in this field. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Plant High-Affinity Potassium (HKT) Transporters Involved in Salinity Tolerance: Structural Insights to Probe Differences in Ion Selectivity
Int. J. Mol. Sci. 2013, 14(4), 7660-7680; doi:10.3390/ijms14047660
Received: 31 January 2013 / Revised: 7 March 2013 / Accepted: 28 March 2013 / Published: 9 April 2013
Cited by 22 | PDF Full-text (1124 KB) | HTML Full-text | XML Full-text
Abstract
High-affinity Potassium Transporters (HKTs) belong to an important class of integral membrane proteins (IMPs) that facilitate cation transport across the plasma membranes of plant cells. Some members of the HKT protein family have been shown to be critical for salinity tolerance in commercially
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High-affinity Potassium Transporters (HKTs) belong to an important class of integral membrane proteins (IMPs) that facilitate cation transport across the plasma membranes of plant cells. Some members of the HKT protein family have been shown to be critical for salinity tolerance in commercially important crop species, particularly in grains, through exclusion of Na+ ions from sensitive shoot tissues in plants. However, given the number of different HKT proteins expressed in plants, it is likely that different members of this protein family perform in a range of functions. Plant breeders and biotechnologists have attempted to manipulate HKT gene expression through genetic engineering and more conventional plant breeding methods to improve the salinity tolerance of commercially important crop plants. Successful manipulation of a biological trait is more likely to be effective after a thorough understanding of how the trait, genes and proteins are interconnected at the whole plant level. This article examines the current structural and functional knowledge relating to plant HKTs and how their structural features may explain their transport selectivity. We also highlight specific areas where new knowledge of plant HKT transporters is needed. Our goal is to present how knowledge of the structure of HKT proteins is helpful in understanding their function and how this understanding can be an invaluable experimental tool. As such, we assert that accurate structural information of plant IMPs will greatly inform functional studies and will lead to a deeper understanding of plant nutrition, signalling and stress tolerance, all of which represent factors that can be manipulated to improve agricultural productivity. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessReview A Dual Role of Strigolactones in Phosphate Acquisition and Utilization in Plants
Int. J. Mol. Sci. 2013, 14(4), 7681-7701; doi:10.3390/ijms14047681
Received: 1 February 2013 / Revised: 22 March 2013 / Accepted: 29 March 2013 / Published: 9 April 2013
Cited by 26 | PDF Full-text (401 KB) | HTML Full-text | XML Full-text
Abstract
Phosphorus, acquired in the form of phosphate (Pi), is one of the primary macronutrients for plants but is least available in the soil. Pi deficiency is a major factor limiting plant growth, development and reproduction. Plants have developed a complex signaling network to
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Phosphorus, acquired in the form of phosphate (Pi), is one of the primary macronutrients for plants but is least available in the soil. Pi deficiency is a major factor limiting plant growth, development and reproduction. Plants have developed a complex signaling network to respond to Pi deficiency. The recent discovery of strigolactones, a new class of plant hormones, has led to an emerging signaling module illustrating the integrated control of Pi acquisition, plant-microbe symbiotic interactions and plant architecture. This review article focuses on the recent findings of plant responses and roles of strigolactones to Pi deficiency. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview A Review of the “Omics” Approach to Biomarkers of Oxidative Stress in Oryza sativa
Int. J. Mol. Sci. 2013, 14(4), 7515-7541; doi:10.3390/ijms14047515
Received: 31 January 2013 / Revised: 20 March 2013 / Accepted: 20 March 2013 / Published: 8 April 2013
Cited by 8 | PDF Full-text (1703 KB) | HTML Full-text | XML Full-text
Abstract
Physiological and ecological constraints that cause the slow growth and depleted production of crops have raised a major concern in the agriculture industry as they represent a possible threat of short food supply in the future. The key feature that regulates the stress
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Physiological and ecological constraints that cause the slow growth and depleted production of crops have raised a major concern in the agriculture industry as they represent a possible threat of short food supply in the future. The key feature that regulates the stress signaling pathway is always related to the reactive oxygen species (ROS). The accumulation of ROS in plant cells would leave traces of biomarkers at the genome, proteome, and metabolome levels, which could be identified with the recent technological breakthrough coupled with improved performance of bioinformatics. This review highlights the recent breakthrough in molecular strategies (comprising transcriptomics, proteomics, and metabolomics) in identifying oxidative stress biomarkers and the arising opportunities and obstacles observed in research on biomarkers in rice. The major issue in incorporating bioinformatics to validate the biomarkers from different omic platforms for the use of rice-breeding programs is also discussed. The development of powerful techniques for identification of oxidative stress-related biomarkers and the integration of data from different disciplines shed light on the oxidative response pathways in plants. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview The Critical Role of Potassium in Plant Stress Response
Int. J. Mol. Sci. 2013, 14(4), 7370-7390; doi:10.3390/ijms14047370
Received: 12 December 2012 / Revised: 23 February 2013 / Accepted: 21 March 2013 / Published: 2 April 2013
Cited by 74 | PDF Full-text (841 KB) | HTML Full-text | XML Full-text
Abstract
Agricultural production continues to be constrained by a number of biotic and abiotic factors that can reduce crop yield quantity and quality. Potassium (K) is an essential nutrient that affects most of the biochemical and physiological processes that influence plant growth and metabolism.
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Agricultural production continues to be constrained by a number of biotic and abiotic factors that can reduce crop yield quantity and quality. Potassium (K) is an essential nutrient that affects most of the biochemical and physiological processes that influence plant growth and metabolism. It also contributes to the survival of plants exposed to various biotic and abiotic stresses. The following review focuses on the emerging role of K in defending against a number of biotic and abiotic stresses, including diseases, pests, drought, salinity, cold and frost and waterlogging. The availability of K and its effects on plant growth, anatomy, morphology and plant metabolism are discussed. The physiological and molecular mechanisms of K function in plant stress resistance are reviewed. This article also evaluates the potential for improving plant stress resistance by modifying K fertilizer inputs and highlights the future needs for research about the role of K in agriculture. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessReview A Central Role for Thiols in Plant Tolerance to Abiotic Stress
Int. J. Mol. Sci. 2013, 14(4), 7405-7432; doi:10.3390/ijms14047405
Received: 4 February 2013 / Revised: 28 February 2013 / Accepted: 14 March 2013 / Published: 2 April 2013
Cited by 76 | PDF Full-text (1062 KB) | HTML Full-text | XML Full-text
Abstract
Abiotic stress poses major problems to agriculture and increasing efforts are being made to understand plant stress response and tolerance mechanisms and to develop new tools that underpin successful agriculture. However, the molecular mechanisms of plant stress tolerance are not fully understood, and
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Abiotic stress poses major problems to agriculture and increasing efforts are being made to understand plant stress response and tolerance mechanisms and to develop new tools that underpin successful agriculture. However, the molecular mechanisms of plant stress tolerance are not fully understood, and the data available is incomplete and sometimes contradictory. Here, we review the significance of protein and non-protein thiol compounds in relation to plant tolerance of abiotic stress. First, the roles of the amino acids cysteine and methionine, are discussed, followed by an extensive discussion of the low-molecular-weight tripeptide, thiol glutathione, which plays a central part in plant stress response and oxidative signalling and of glutathione-related enzymes, including those involved in the biosynthesis of non-protein thiol compounds. Special attention is given to the glutathione redox state, to phytochelatins and to the role of glutathione in the regulation of the cell cycle. The protein thiol section focuses on glutaredoxins and thioredoxins, proteins with oxidoreductase activity, which are involved in protein glutathionylation. The review concludes with a brief overview of and future perspectives for the involvement of plant thiols in abiotic stress tolerance. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Impact of Cell Wall Composition on Maize Resistance to Pests and Diseases
Int. J. Mol. Sci. 2013, 14(4), 6960-6980; doi:10.3390/ijms14046960
Received: 18 February 2013 / Revised: 19 March 2013 / Accepted: 20 March 2013 / Published: 27 March 2013
Cited by 20 | PDF Full-text (563 KB) | HTML Full-text | XML Full-text
Abstract
In cereals, the primary cell wall is built of a skeleton of cellulosic microfibrils embedded in a matrix of hemicelluloses and smaller amounts of pectins, glycoproteins and hydroxycinnamates. Later, during secondary wall development, p-coumaryl, coniferyl and sinapyl alcohols are copolymerized to form
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In cereals, the primary cell wall is built of a skeleton of cellulosic microfibrils embedded in a matrix of hemicelluloses and smaller amounts of pectins, glycoproteins and hydroxycinnamates. Later, during secondary wall development, p-coumaryl, coniferyl and sinapyl alcohols are copolymerized to form mixed lignins. Several of these cell wall components show a determinative role in maize resistance to pest and diseases. However, defense mechanisms are very complex and vary among the same plant species, different tissues or even the same tissue at different developmental stages. Thus, it is important to highlight that the role of the cell wall components needs to be tested in diverse genotypes and specific tissues where the feeding or attacking by the pathogen takes place. Understanding the role of cell wall constituents as defense mechanisms may allow modifications of crops to withstand pests and diseases. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessReview Protein Contribution to Plant Salinity Response and Tolerance Acquisition
Int. J. Mol. Sci. 2013, 14(4), 6757-6789; doi:10.3390/ijms14046757
Received: 25 January 2013 / Revised: 25 February 2013 / Accepted: 26 February 2013 / Published: 26 March 2013
Cited by 37 | PDF Full-text (436 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The review is focused on plant proteome response to salinity with respect to physiological aspects of plant salt stress response. The attention is paid to both osmotic and ionic effects of salinity stress on plants with respect to several protein functional groups. Therefore,
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The review is focused on plant proteome response to salinity with respect to physiological aspects of plant salt stress response. The attention is paid to both osmotic and ionic effects of salinity stress on plants with respect to several protein functional groups. Therefore, the role of individual proteins involved in signalling, changes in gene expression, protein biosynthesis and degradation and the resulting changes in protein relative abundance in proteins involved in energy metabolism, redox metabolism, stress- and defence-related proteins, osmolyte metabolism, phytohormone, lipid and secondary metabolism, mechanical stress-related proteins as well as protein posttranslational modifications are discussed. Differences between salt-sensitive (glycophytes) and salt-tolerant (halophytes) plants are analysed with respect to differential salinity tolerance. In conclusion, contribution of proteomic studies to understanding plant salinity tolerance is summarised and discussed. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Alternative Oxidase: A Mitochondrial Respiratory Pathway to Maintain Metabolic and Signaling Homeostasis during Abiotic and Biotic Stress in Plants
Int. J. Mol. Sci. 2013, 14(4), 6805-6847; doi:10.3390/ijms14046805
Received: 16 February 2013 / Revised: 8 March 2013 / Accepted: 12 March 2013 / Published: 26 March 2013
Cited by 107 | PDF Full-text (444 KB) | HTML Full-text | XML Full-text
Abstract
Alternative oxidase (AOX) is a non-energy conserving terminal oxidase in the plant mitochondrial electron transport chain. While respiratory carbon oxidation pathways, electron transport, and ATP turnover are tightly coupled processes, AOX provides a means to relax this coupling, thus providing a degree of
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Alternative oxidase (AOX) is a non-energy conserving terminal oxidase in the plant mitochondrial electron transport chain. While respiratory carbon oxidation pathways, electron transport, and ATP turnover are tightly coupled processes, AOX provides a means to relax this coupling, thus providing a degree of metabolic homeostasis to carbon and energy metabolism. Beside their role in primary metabolism, plant mitochondria also act as “signaling organelles”, able to influence processes such as nuclear gene expression. AOX activity can control the level of potential mitochondrial signaling molecules such as superoxide, nitric oxide and important redox couples. In this way, AOX also provides a degree of signaling homeostasis to the organelle. Evidence suggests that AOX function in metabolic and signaling homeostasis is particularly important during stress. These include abiotic stresses such as low temperature, drought, and nutrient deficiency, as well as biotic stresses such as bacterial infection. This review provides an introduction to the genetic and biochemical control of AOX respiration, as well as providing generalized examples of how AOX activity can provide metabolic and signaling homeostasis. This review also examines abiotic and biotic stresses in which AOX respiration has been critically evaluated, and considers the overall role of AOX in growth and stress tolerance. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessReview The Influence of Metal Stress on the Availability and Redox State of Ascorbate, and Possible Interference with Its Cellular Functions
Int. J. Mol. Sci. 2013, 14(3), 6382-6413; doi:10.3390/ijms14036382
Received: 1 February 2013 / Revised: 6 March 2013 / Accepted: 8 March 2013 / Published: 20 March 2013
Cited by 8 | PDF Full-text (827 KB) | HTML Full-text | XML Full-text
Abstract
Worldwide, metals have been distributed to excessive levels in the environment due to industrial and agricultural activities. Plants growing on soils contaminated with excess levels of metals experience a disturbance of the cellular redox balance, which leads to an augmentation of reactive oxygen
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Worldwide, metals have been distributed to excessive levels in the environment due to industrial and agricultural activities. Plants growing on soils contaminated with excess levels of metals experience a disturbance of the cellular redox balance, which leads to an augmentation of reactive oxygen species (ROS). Even though the increased ROS levels can cause cellular damage, controlled levels play an important role in modulating signaling networks that control physiological processes and stress responses. Plants control ROS levels using their antioxidative defense system both under non-stress conditions, as well as under stress conditions such as exposure to excess metals. Ascorbate (AsA) is a well-known and important component of the plant’s antioxidative system. As primary antioxidant, it can reduce ROS directly and indirectly via ascorbate peroxidase in the ascorbate–glutathione cycle. Furthermore, AsA fulfills an essential role in physiological processes, some of which are disturbed by excess metals. In this review, known direct effects of excess metals on AsA biosynthesis and functioning will be discussed, as well as the possible interference of metals with the role of AsA in physiological and biochemical processes. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Structure, Function and Networks of Transcription Factors Involved in Abiotic Stress Responses
Int. J. Mol. Sci. 2013, 14(3), 5842-5878; doi:10.3390/ijms14035842
Received: 4 February 2013 / Revised: 5 March 2013 / Accepted: 5 March 2013 / Published: 13 March 2013
Cited by 62 | PDF Full-text (2014 KB) | HTML Full-text | XML Full-text
Abstract
Transcription factors (TFs) are master regulators of abiotic stress responses in plants. This review focuses on TFs from seven major TF families, known to play functional roles in response to abiotic stresses, including drought, high salinity, high osmolarity, temperature extremes and the phytohormone
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Transcription factors (TFs) are master regulators of abiotic stress responses in plants. This review focuses on TFs from seven major TF families, known to play functional roles in response to abiotic stresses, including drought, high salinity, high osmolarity, temperature extremes and the phytohormone ABA. Although ectopic expression of several TFs has improved abiotic stress tolerance in plants, fine-tuning of TF expression and protein levels remains a challenge to avoid crop yield loss. To further our understanding of TFs in abiotic stress responses, emerging gene regulatory networks based on TFs and their direct targets genes are presented. These revealed components shared between ABA-dependent and independent signaling as well as abiotic and biotic stress signaling. Protein structure analysis suggested that TFs hubs of large interactomes have extended regions with protein intrinsic disorder (ID), referring to their lack of fixed tertiary structures. ID is now an emerging topic in plant science. Furthermore, the importance of the ubiquitin-proteasome protein degradation systems and modification by sumoylation is also apparent from the interactomes. Therefore; TF interaction partners such as E3 ubiquitin ligases and TF regions with ID represent future targets for engineering improved abiotic stress tolerance in crops. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Structural Biology of a Major Signaling Network that Regulates Plant Abiotic Stress: The CBL-CIPK Mediated Pathway
Int. J. Mol. Sci. 2013, 14(3), 5734-5749; doi:10.3390/ijms14035734
Received: 31 January 2013 / Revised: 27 February 2013 / Accepted: 28 February 2013 / Published: 12 March 2013
Cited by 13 | PDF Full-text (2199 KB) | HTML Full-text | XML Full-text
Abstract
The Arabidopsis SOS2 family of twenty-six protein kinases (CIPKs), their interacting activators, the SOS3 family of ten calcium-binding proteins (CBLs) and protein phosphatases type 2C (PP2C), function together in decoding calcium signals elicited by different environmental stimuli. Biochemical data suggest that stable CBL-CIPK
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The Arabidopsis SOS2 family of twenty-six protein kinases (CIPKs), their interacting activators, the SOS3 family of ten calcium-binding proteins (CBLs) and protein phosphatases type 2C (PP2C), function together in decoding calcium signals elicited by different environmental stimuli. Biochemical data suggest that stable CBL-CIPK or CIPK-PP2C complexes may be regulating the activity of various substrates controlling ion homeostasis. The available structural information provides a general regulatory mechanism in which calcium perception by CBLs and kinase activation is coupled. The structural basis of this molecular mechanism and the specificity of the network is reviewed and discussed in detail. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessReview Cold Signaling and Cold Response in Plants
Int. J. Mol. Sci. 2013, 14(3), 5312-5337; doi:10.3390/ijms14035312
Received: 31 January 2013 / Revised: 26 February 2013 / Accepted: 26 February 2013 / Published: 6 March 2013
Cited by 73 | PDF Full-text (473 KB) | HTML Full-text | XML Full-text
Abstract
Plants are constantly exposed to a variety of environmental stresses. Freezing or extremely low temperature constitutes a key factor influencing plant growth, development and crop productivity. Plants have evolved a mechanism to enhance tolerance to freezing during exposure to periods of low, but
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Plants are constantly exposed to a variety of environmental stresses. Freezing or extremely low temperature constitutes a key factor influencing plant growth, development and crop productivity. Plants have evolved a mechanism to enhance tolerance to freezing during exposure to periods of low, but non-freezing temperatures. This phenomenon is called cold acclimation. During cold acclimation, plants develop several mechanisms to minimize potential damages caused by low temperature. Cold response is highly complex process that involves an array of physiological and biochemical modifications. Furthermore, alterations of the expression patterns of many genes, proteins and metabolites in response to cold stress have been reported. Recent studies demonstrate that post-transcriptional and post-translational regulations play a role in the regulation of cold signaling. In this review article, recent advances in cold stress signaling and tolerance are highlighted. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Metabolomics as a Tool to Investigate Abiotic Stress Tolerance in Plants
Int. J. Mol. Sci. 2013, 14(3), 4885-4911; doi:10.3390/ijms14034885
Received: 31 December 2012 / Revised: 18 February 2013 / Accepted: 20 February 2013 / Published: 1 March 2013
Cited by 66 | PDF Full-text (527 KB) | HTML Full-text | XML Full-text
Abstract
Metabolites reflect the integration of gene expression, protein interaction and other different regulatory processes and are therefore closer to the phenotype than mRNA transcripts or proteins alone. Amongst all –omics technologies, metabolomics is the most transversal and can be applied to different organisms
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Metabolites reflect the integration of gene expression, protein interaction and other different regulatory processes and are therefore closer to the phenotype than mRNA transcripts or proteins alone. Amongst all –omics technologies, metabolomics is the most transversal and can be applied to different organisms with little or no modifications. It has been successfully applied to the study of molecular phenotypes of plants in response to abiotic stress in order to find particular patterns associated to stress tolerance. These studies have highlighted the essential involvement of primary metabolites: sugars, amino acids and Krebs cycle intermediates as direct markers of photosynthetic dysfunction as well as effectors of osmotic readjustment. On the contrary, secondary metabolites are more specific of genera and species and respond to particular stress conditions as antioxidants, Reactive Oxygen Species (ROS) scavengers, coenzymes, UV and excess radiation screen and also as regulatory molecules. In addition, the induction of secondary metabolites by several abiotic stress conditions could also be an effective mechanism of cross-protection against biotic threats, providing a link between abiotic and biotic stress responses. Moreover, the presence/absence and relative accumulation of certain metabolites along with gene expression data provides accurate markers (mQTL or MWAS) for tolerant crop selection in breeding programs. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
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Open AccessReview Low Oxygen Response Mechanisms in Green Organisms
Int. J. Mol. Sci. 2013, 14(3), 4734-4761; doi:10.3390/ijms14034734
Received: 29 January 2013 / Revised: 20 February 2013 / Accepted: 21 February 2013 / Published: 27 February 2013
Cited by 22 | PDF Full-text (872 KB) | HTML Full-text | XML Full-text
Abstract
Low oxygen stress often occurs during the life of green organisms, mostly due to the environmental conditions affecting oxygen availability. Both plants and algae respond to low oxygen by resetting their metabolism. The shift from mitochondrial respiration to fermentation is the hallmark of
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Low oxygen stress often occurs during the life of green organisms, mostly due to the environmental conditions affecting oxygen availability. Both plants and algae respond to low oxygen by resetting their metabolism. The shift from mitochondrial respiration to fermentation is the hallmark of anaerobic metabolism in most organisms. This involves a modified carbohydrate metabolism coupled with glycolysis and fermentation. For a coordinated response to low oxygen, plants exploit various molecular mechanisms to sense when oxygen is either absent or in limited amounts. In Arabidopsis thaliana, a direct oxygen sensing system has recently been discovered, where a conserved N-terminal motif on some ethylene responsive factors (ERFs), targets the fate of the protein under normoxia/hypoxia. In Oryza sativa, this same group of ERFs drives physiological and anatomical modifications that vary in relation to the genotype studied. The microalga Chlamydomonas reinhardtii responses to low oxygen seem to have evolved independently of higher plants, posing questions on how the fermentative metabolism is modulated. In this review, we summarize the most recent findings related to these topics, highlighting promising developments for the future. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Regulation of Translation Initiation under Biotic and Abiotic Stresses
Int. J. Mol. Sci. 2013, 14(3), 4670-4683; doi:10.3390/ijms14034670
Received: 15 January 2013 / Revised: 20 February 2013 / Accepted: 20 February 2013 / Published: 26 February 2013
Cited by 11 | PDF Full-text (194 KB) | HTML Full-text | XML Full-text
Abstract
Plants have developed versatile strategies to deal with the great variety of challenging conditions they are exposed to. Among them, the regulation of translation is a common target to finely modulate gene expression both under biotic and abiotic stress situations. Upon environmental challenges,
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Plants have developed versatile strategies to deal with the great variety of challenging conditions they are exposed to. Among them, the regulation of translation is a common target to finely modulate gene expression both under biotic and abiotic stress situations. Upon environmental challenges, translation is regulated to reduce the consumption of energy and to selectively synthesize proteins involved in the proper establishment of the tolerance response. In the case of viral infections, the situation is more complex, as viruses have evolved unconventional mechanisms to regulate translation in order to ensure the production of the viral encoded proteins using the plant machinery. Although the final purpose is different, in some cases, both plants and viruses share common mechanisms to modulate translation. In others, the mechanisms leading to the control of translation are viral- or stress-specific. In this paper, we review the different mechanisms involved in the regulation of translation initiation under virus infection and under environmental stress in plants. In addition, we describe the main features within the viral RNAs and the cellular mRNAs that promote their selective translation in plants undergoing biotic and abiotic stress situations. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)
Open AccessReview Activation of Defense Mechanisms against Pathogens in Mosses and Flowering Plants
Int. J. Mol. Sci. 2013, 14(2), 3178-3200; doi:10.3390/ijms14023178
Received: 4 January 2013 / Revised: 23 January 2013 / Accepted: 23 January 2013 / Published: 4 February 2013
Cited by 28 | PDF Full-text (407 KB) | HTML Full-text | XML Full-text
Abstract
During evolution, plants have developed mechanisms to cope with and adapt to different types of stress, including microbial infection. Once the stress is sensed, signaling pathways are activated, leading to the induced expression of genes with different roles in defense. Mosses (Bryophytes) are
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During evolution, plants have developed mechanisms to cope with and adapt to different types of stress, including microbial infection. Once the stress is sensed, signaling pathways are activated, leading to the induced expression of genes with different roles in defense. Mosses (Bryophytes) are non-vascular plants that diverged from flowering plants more than 450 million years ago, allowing comparative studies of the evolution of defense-related genes and defensive metabolites produced after microbial infection. The ancestral position among land plants, the sequenced genome and the feasibility of generating targeted knock-out mutants by homologous recombination has made the moss Physcomitrella patens an attractive model to perform functional studies of plant genes involved in stress responses. This paper reviews the current knowledge of inducible defense mechanisms in P. patens and compares them to those activated in flowering plants after pathogen assault, including the reinforcement of the cell wall, ROS production, programmed cell death, activation of defense genes and synthesis of secondary metabolites and defense hormones. The knowledge generated in P. patens together with comparative studies in flowering plants will help to identify key components in plant defense responses and to design novel strategies to enhance resistance to biotic stress. Full article
(This article belongs to the Special Issue Abiotic and Biotic Stress Tolerance Mechanisms in Plants)

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