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Special Issue "Plant Defense Genes Against Biotic Stresses"

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Plant Sciences".

Deadline for manuscript submissions: closed (30 June 2018)

Special Issue Editor

Guest Editor
Prof. Dr. Isabel Díaz Rodríguez

Universidad Politecnica de Madrid, Centro de Biotecnología y Genómica de Plantas, Madrid, Spain
Website | E-Mail
Interests: molecular events in the plant-pest interactions; plant perception and responses to phytophagous insects and mites; biotic stresses; control of pests and pathogens

Special Issue Information

Dear Colleagues,

Plant–pest and pathogen relationships are intricate interactions encompassing complex networks of molecules and signalling pathways and strategies to overcome defenses developed by each other. The induction of plant defense genes is initiated when specific receptors recognize either the presence of a pathogen (fungi, bacteria, and virus), or a pest (phytophagous insect, acai, or nematode), or the damage incurred by them, or even the existence of volatiles, emitted as plant–plant cues. The success of plants in withstanding biotic stresses depends on their fast response by triggering a wide range of specific genes and compounds with defense properties. These plant defences locally or systemically induced by biotic stresses are regulated by a complex hormonal cross-talk. Transcriptomic and proteomic profiles have demonstrated that plants may discriminate among species of pathogens and pests and activate specific responses. Metabolomic approaches have corroborated plants’ ability to differentiate species and determine the onset of indirect defense responses to complement the direct defenses.

This Special Issue calls all researchers involved in deciphering how plants use a wide and specific battery of genes to fight against pathogens and pests. Original articles and reviews covering all aspects on the understanding in the field of plant response to biotic stresses are welcome.

Prof. Dr. Isabel Diaz
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • early and late plant responses to pathogens and pest
  • elicitors, effectors and plant receptors
  • direct and indirect plant defense
  • plant signal transduction and gene expression
  • hormonal crosstalk in plant defenses
  • plant defense and fitness
  • plant-microbe interactions
  • plant-pest interactions
  • plant defenses against multiple

Published Papers (25 papers)

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Open AccessEditorial Plant Defense Genes against Biotic Stresses
Int. J. Mol. Sci. 2018, 19(8), 2446; https://doi.org/10.3390/ijms19082446
Received: 8 August 2018 / Accepted: 18 August 2018 / Published: 19 August 2018
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(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)

Research

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Open AccessArticle Identification of Novel Quantitative Trait Loci Linked to Crown Rot Resistance in Spring Wheat
Int. J. Mol. Sci. 2018, 19(9), 2666; https://doi.org/10.3390/ijms19092666
Received: 25 June 2018 / Revised: 17 August 2018 / Accepted: 25 August 2018 / Published: 8 September 2018
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Abstract
Crown rot (CR), caused by various Fusarium species, is a major disease in many cereal-growing regions worldwide. Fusarium culmorum is one of the most important species, which can cause significant yield losses in wheat. A set of 126 advanced International Maize and Wheat
[...] Read more.
Crown rot (CR), caused by various Fusarium species, is a major disease in many cereal-growing regions worldwide. Fusarium culmorum is one of the most important species, which can cause significant yield losses in wheat. A set of 126 advanced International Maize and Wheat Improvement Center (CIMMYT) spring bread wheat lines were phenotyped against CR for field crown, greenhouse crown and stem, and growth room crown resistance scores. Of these, 107 lines were genotyped using Diversity Array Technology (DArT) markers to identify quantitative trait loci linked to CR resistance by genome-wide association study. Results of the population structure analysis grouped the accessions into three sub-groups. Genome wide linkage disequilibrium was large and declined on average within 20 cM (centi-Morgan) in the panel. General linear model (GLM), mixed linear model (MLM), and naïve models were tested for each CR score and the best model was selected based on quarantine-quarantine plots. Three marker-trait associations (MTAs) were identified linked to CR resistance; two of these on chromosome 3B were associated with field crown scores, each explaining 11.4% of the phenotypic variation and the third MTA on chromosome 2D was associated with greenhouse stem score and explained 11.6% of the phenotypic variation. Together, these newly identified loci provide opportunity for wheat breeders to exploit in enhancing CR resistance via marker-assisted selection or deployment in genomic selection in wheat breeding programs. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Suppression of Plant Defenses by Herbivorous Mites Is Not Associated with Adaptation to Host Plants
Int. J. Mol. Sci. 2018, 19(6), 1783; https://doi.org/10.3390/ijms19061783
Received: 23 May 2018 / Accepted: 12 June 2018 / Published: 15 June 2018
Cited by 1 | PDF Full-text (1884 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Some herbivores suppress plant defenses, which may be viewed as a result of the coevolutionary arms race between plants and herbivores. However, this ability is usually studied in a one-herbivore-one-plant system, which hampers comparative studies that could corroborate this hypothesis. Here, we extend
[...] Read more.
Some herbivores suppress plant defenses, which may be viewed as a result of the coevolutionary arms race between plants and herbivores. However, this ability is usually studied in a one-herbivore-one-plant system, which hampers comparative studies that could corroborate this hypothesis. Here, we extend this paradigm and ask whether the herbivorous spider-mite Tetranychus evansi, which suppresses the jasmonic-acid pathway in tomato plants, is also able to suppress defenses in other host plants at different phylogenetic distances from tomatoes. We test this using different plants from the Solanales order, namely tomato, jimsonweed, tobacco, and morning glory (three Solanaceae and one Convolvulaceae), and bean plants (Fabales). First, we compare the performance of T. evansi to that of the other two most-commonly found species of the same genus, T. urticae and T. ludeni, on several plants. We found that the performance of T. evansi is higher than that of the other species only on tomato plants. We then showed, by measuring trypsin inhibitor activity and life history traits of conspecific mites on either clean or pre-infested plants, that T. evansi can suppress plant defenses on all plants except tobacco. This study suggests that the suppression of plant defenses may occur on host plants other than those to which herbivores are adapted. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Transient Overexpression of HvSERK2 Improves Barley Resistance to Powdery Mildew
Int. J. Mol. Sci. 2018, 19(4), 1226; https://doi.org/10.3390/ijms19041226
Received: 23 March 2018 / Revised: 14 April 2018 / Accepted: 15 April 2018 / Published: 18 April 2018
Cited by 1 | PDF Full-text (3326 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Somatic embryogenesis receptor-like kinases (SERKs) play an essential role in plant response to pathogen infection. Here we identified three SERK genes (HvSERK1/2/3) from barley, and aimed to determine their implication in defense responses to barley powdery mildew (Bgh). Although
[...] Read more.
Somatic embryogenesis receptor-like kinases (SERKs) play an essential role in plant response to pathogen infection. Here we identified three SERK genes (HvSERK1/2/3) from barley, and aimed to determine their implication in defense responses to barley powdery mildew (Bgh). Although HvSERK1/2/3 share the characteristic domains of the SERK family, only HvSERK2 was significantly induced in barley leaves during Bgh infection. The expression of HvSERK2 was rapidly induced by hydrogen peroxide (H2O2) treatment, but not by treatment with salicylic acid (SA), methyl jasmonate (MeJA), ethephon (ETH), or abscisic acid (ABA). Bioinformatics analysis of the cloned HvSERK2 promoter revealed that it contains several elements responsible for defense responses against pathogens. Promoter functional analysis showed that the HvSERK2 promoter was induced by Bgh and H2O2. Subcellular localization analysis of HvSERK2 indicated that it is mainly located on the plasma membrane. Transient overexpression of HvSERK2 in epidermal cells of the susceptible barley cultivar Hua 30 reduced the Bgh haustorium index from 58.6% to 43.2%. This study suggests that the HvSERK2 gene plays a positive role in the improvement of barley resistance to powdery mildew, and provides new insight into the function of SERK genes in the biotic stress response of plants. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Molecular and Ultrastructural Mechanisms Underlying Yellow Dwarf Symptom Formation in Wheat after Infection of Barley Yellow Dwarf Virus
Int. J. Mol. Sci. 2018, 19(4), 1187; https://doi.org/10.3390/ijms19041187
Received: 16 March 2018 / Revised: 5 April 2018 / Accepted: 6 April 2018 / Published: 13 April 2018
Cited by 1 | PDF Full-text (12684 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Wheat (Tritium aestivum L.) production is essential for global food security. Infection of barley yellow dwarf virus-GAV (BYDV-GAV) results in wheat showing leaf yellowing and plant dwarfism symptom. To explore the molecular and ultrastructural mechanisms underlying yellow dwarf symptom formation in BYDV-GAV-infected
[...] Read more.
Wheat (Tritium aestivum L.) production is essential for global food security. Infection of barley yellow dwarf virus-GAV (BYDV-GAV) results in wheat showing leaf yellowing and plant dwarfism symptom. To explore the molecular and ultrastructural mechanisms underlying yellow dwarf symptom formation in BYDV-GAV-infected wheat, we investigated the chloroplast ultrastructure via transmission electron microscopy (TEM), examined the contents of the virus, H2O2, and chlorophyll in Zhong8601, and studied the comparative transcriptome through microarray analyses in the susceptible wheat line Zhong8601 after virus infection. TEM images indicated that chloroplasts in BYDV-GAV-infected Zhong8601 leaf cells were fragmentized. Where thylakoids were not well developed, starch granules and plastoglobules were rare. Compared with mock-inoculated Zhong8601, chlorophyll content was markedly reduced, but the virus and H2O2 contents were significantly higher in BYDV-GAV-infected Zhong8601. The transcriptomic analyses revealed that chlorophyll biosynthesis and chloroplast related transcripts, encoding chlorophyll a/b binding protein, glucose-6-phosphate/phosphate translocator 2, and glutamyl-tRNA reductase 1, were down-regulated in BYDV-GAV-infected Zhong8601. Some phytohormone signaling-related transcripts, including abscisic acid (ABA) signaling factors (phospholipase D alpha 1 and calcineurin B-like protein 9) and nine ethylene response factors, were up-regulated. Additionally, reactive oxygen species (ROS)-related genes were transcriptionally regulated in BYDV-GAV infected Zhong8601, including three up-regulated transcripts encoding germin-like proteins (promoting ROS accumulation) and four down-regulated transcripts encoding peroxides (scavenging ROS). These results clearly suggest that the yellow dwarf symptom formation is mainly attributed to reduced chlorophyll content and fragmentized chloroplasts caused by down-regulation of the chlorophyll and chloroplast biosynthesis related genes, ROS excessive accumulation, and precisely transcriptional regulation of the above-mentioned ABA and ethylene signaling- and ROS-related genes in susceptible wheat infected by BYDV-GAV. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Genome-Wide Analysis of DCL, AGO, and RDR Gene Families in Pepper (Capsicum Annuum L.)
Int. J. Mol. Sci. 2018, 19(4), 1038; https://doi.org/10.3390/ijms19041038
Received: 28 January 2018 / Revised: 26 March 2018 / Accepted: 27 March 2018 / Published: 30 March 2018
Cited by 1 | PDF Full-text (31111 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
RNA silencing is an evolutionarily conserved mechanism that regulates variety of cellular processes in plants. Argonaute protein (AGO), Dicer-like protein (DCL) and RNA-dependent RNA polymerase (RDR) are critical components of RNA silencing. These efficient and indispensable components of the RNAi pathway have not
[...] Read more.
RNA silencing is an evolutionarily conserved mechanism that regulates variety of cellular processes in plants. Argonaute protein (AGO), Dicer-like protein (DCL) and RNA-dependent RNA polymerase (RDR) are critical components of RNA silencing. These efficient and indispensable components of the RNAi pathway have not been identified and characterized in pepper. In this study, we identified 12 CaAGO, 4 CaDCL and 6 CaRDR genes in pepper and compared them with those of Arabidopsis, tobacco, potato and tomato. Detailed phylogenetic analyses revealed that each CaAGO, CaDCL and CaRDR protein family were classified into four clades. The tissue specific expression and respond to abiotic or biotic stress were studied. The real-time quantitative polymerase chain reaction (PCR) results demonstrated that CaAGO2, CaAGO10b, CaDCL2 and CaDCL4 were upregulated with cucumber mosaic virus (CMV), potato virus Y (PVY) and tobacco mosaic virus (TMV) infections, whereas they showed difference expression patterns in response to abiotic stress. In addition, we found that many of the candidate genes were induced by phytohormones and H2O2 treatment. Our results provide useful information for further elucidation of gene silencing pathways and RNAi-mediated host immunity in pepper. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Transcriptome Analysis Identifies a 140 kb Region of Chromosome 3B Containing Genes Specific to Fusarium Head Blight Resistance in Wheat
Int. J. Mol. Sci. 2018, 19(3), 852; https://doi.org/10.3390/ijms19030852
Received: 4 February 2018 / Revised: 11 March 2018 / Accepted: 12 March 2018 / Published: 14 March 2018
Cited by 1 | PDF Full-text (5181 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Fusarium head blight (FHB), mainly caused by Fusarium graminearum, is one of the most destructive fungal diseases of wheat (Triticum aestivum L.). Because of the quantitative nature of FHB resistance, its mechanism is poorly understood. We conducted a comparative transcriptome analysis
[...] Read more.
Fusarium head blight (FHB), mainly caused by Fusarium graminearum, is one of the most destructive fungal diseases of wheat (Triticum aestivum L.). Because of the quantitative nature of FHB resistance, its mechanism is poorly understood. We conducted a comparative transcriptome analysis to identify genes that are differentially expressed in FHB-resistant and FHB-susceptible wheat lines grown under field conditions for various periods after F. graminearum infection and determined the chromosomal distribution of the differentially expressed genes (DEGs). For each line, the expression in the spike (which exhibits symptoms in the infected plants) was compared with that in the flag leaves (which do not exhibit symptoms in the infected plants). We identified an island of 53 constitutive DEGs in a 140 kb region with high homology to the FhbL693b region on chromosome 3B. Of these genes, 13 were assigned to specific chloroplast-related pathways. Furthermore, one gene encoded inositol monophosphate (IMPa) and two genes encoded ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Our findings suggest that the temporary susceptibility in locally infected spikes results from the cross-talk between RuBisCO and IMPa, which blocks secondary signaling pathways mediated by salicylic acid and induces a systemic acquired resistance in the distant leaf tissue. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Molecular Characterization and Overexpression of VpRPW8s from Vitis pseudoreticulata Enhances Resistance to Phytophthora capsici in Nicotiana benthamiana
Int. J. Mol. Sci. 2018, 19(3), 839; https://doi.org/10.3390/ijms19030839
Received: 24 January 2018 / Revised: 25 February 2018 / Accepted: 27 February 2018 / Published: 13 March 2018
Cited by 1 | PDF Full-text (5089 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
RPW8 genes are atypical broad-spectrum genes that provide resistance to powdery mildew, downy mildew, the cauliflower mosaic virus in Arabidopsis thaliana, and powdery mildew in tobacco. They play important roles in basal plant pathogen defense. They also provide insights into a novel
[...] Read more.
RPW8 genes are atypical broad-spectrum genes that provide resistance to powdery mildew, downy mildew, the cauliflower mosaic virus in Arabidopsis thaliana, and powdery mildew in tobacco. They play important roles in basal plant pathogen defense. They also provide insights into a novel disease resistance mechanism. In this study, we report on homologous RPW8 genes in Vitis pseudoreticulata. Five VpRPW8 genes were cloned; their Open Reading Frame (ORF) sequences ranged from 1994 base pairs to 2478 base pairs. They were comprised of five exons and four introns and shared 78.66% identity. Their proteins had typical conserved RPW8 and NB-LRR (the nucleotide-binding site and the leucine-rich repeats) domains (except VpRPW8-d, which lacked LRR domains). Prokaryotic expression results were consistent with predicted molecular weights. All five RPW8 genes were located in the cytoplasm. Quantitative real-time PCR (qRT-PCR) analysis showed that VpRPW8s in V. pseudoreticulata were induced by Plasmopara viticola, but nearly only VvRPW8-d genes were induced in Vitis vinifera. Furthermore, a VpRPW8 transgenic tobacco system was established. Overexpressed VpRPW8s enhanced resistance to Phytophthora capsici and VpRPW8s conferred varying degrees of resistance to Ph. capsici in Nicotiana benthamiana. Our study presents novel members of the plant RPW8 family and suggests that VpRPW8s are involved in enhanced resistance to P. viticola and Ph. capsici. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Overexpression of HvIcy6 in Barley Enhances Resistance against Tetranychus urticae and Entails Partial Transcriptomic Reprogramming
Int. J. Mol. Sci. 2018, 19(3), 697; https://doi.org/10.3390/ijms19030697
Received: 29 January 2018 / Revised: 22 February 2018 / Accepted: 27 February 2018 / Published: 1 March 2018
Cited by 3 | PDF Full-text (2565 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Cystatins have been largely used for pest control against phytophagous species. However, cystatins have not been commonly overexpressed in its cognate plant species to test their pesticide capacity. Since the inhibitory role of barley HvCPI-6 cystatin against the phytophagous mite Tetranychus urticae has
[...] Read more.
Cystatins have been largely used for pest control against phytophagous species. However, cystatins have not been commonly overexpressed in its cognate plant species to test their pesticide capacity. Since the inhibitory role of barley HvCPI-6 cystatin against the phytophagous mite Tetranychus urticae has been previously demonstrated, the purpose of our study was to determine if barley transgenic lines overexpressing its own HvIcy6 gene were more resistant against this phytophagous infestation. Besides, a transcriptomic analysis was done to find differential expressed genes among wild-type and transformed barley plants. Barley plants overexpressing HvIcy6 cystatin gene remained less susceptible to T. urticae attack when compared to wild-type plants, with a significant lesser foliar damaged area and a lower presence of the mite. Transcriptomic analysis revealed a certain reprogramming of cellular metabolism and a lower expression of several genes related to photosynthetic activity. Therefore, although caution should be taken to discard potential deleterious pleiotropic effects, cystatins may be used as transgenes with impact on agricultural crops by conferring enhanced levels of resistance to phytophagous pests. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Expression of Vitis amurensis VaERF20 in Arabidopsis thaliana Improves Resistance to Botrytis cinerea and Pseudomonas syringae pv. Tomato DC3000
Int. J. Mol. Sci. 2018, 19(3), 696; https://doi.org/10.3390/ijms19030696
Received: 10 January 2018 / Revised: 2 February 2018 / Accepted: 6 February 2018 / Published: 1 March 2018
Cited by 2 | PDF Full-text (8031 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Ethylene response factor (ERF) transcription factors play important roles in regulating immune responses in plants. In our study, we characterized a member of the ERF transcription factor family, VaERF20, from the Chinese wild Vitis genotype, V. amurensis Rupr “Shuangyou”. Phylogenetic analysis indicated
[...] Read more.
Ethylene response factor (ERF) transcription factors play important roles in regulating immune responses in plants. In our study, we characterized a member of the ERF transcription factor family, VaERF20, from the Chinese wild Vitis genotype, V. amurensis Rupr “Shuangyou”. Phylogenetic analysis indicated that VaERF20 belongs to group IXc of the ERF family, in which many members are known to contribute to fighting pathogen infection. Consistent with this, expression of VaERF20 was induced by treatment with the necrotrophic fungal pathogen Botrytis cinerea (B. cinerea) in “Shuangyou” and V. vinifera “Red Globe”. Arabidopsis thaliana plants over-expressing VaERF20 displayed enhanced resistance to B. cinerea and the bacterium Pseudomonas syringae pv. tomato (Pst) DC3000. Patterns of pathogen-induced reactive oxygen species (ROS) accumulation were entirely distinct in B. cinerea and PstDC3000 inoculated plants. Examples of both salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) responsive defense genes were up-regulated after B. cinerea and PstDC3000 inoculation of the VaERF20-overexpressing transgenic A. thaliana plants. Evidence of pattern-triggered immunity (PTI), callose accumulation and stomatal defense, together with increased expression of PTI genes, was also greater in the transgenic lines. These data indicate that VaERF20 participates in various signal transduction pathways and acts as an inducer of immune responses. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle A Phenotyping Method of Giant Cells from Root-Knot Nematode Feeding Sites by Confocal Microscopy Highlights a Role for CHITINASE-LIKE 1 in Arabidopsis
Int. J. Mol. Sci. 2018, 19(2), 429; https://doi.org/10.3390/ijms19020429
Received: 21 December 2017 / Revised: 19 January 2018 / Accepted: 26 January 2018 / Published: 1 February 2018
Cited by 2 | PDF Full-text (6903 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Most effective nematicides for the control of root-knot nematodes are banned, which demands a better understanding of the plant-nematode interaction. Understanding how gene expression in the nematode-feeding sites relates to morphological features may assist a better characterization of the interaction. However, nematode-induced galls
[...] Read more.
Most effective nematicides for the control of root-knot nematodes are banned, which demands a better understanding of the plant-nematode interaction. Understanding how gene expression in the nematode-feeding sites relates to morphological features may assist a better characterization of the interaction. However, nematode-induced galls resulting from cell-proliferation and hypertrophy hinders such observation, which would require tissue sectioning or clearing. We demonstrate that a method based on the green auto-fluorescence produced by glutaraldehyde and the tissue-clearing properties of benzyl-alcohol/benzyl-benzoate preserves the structure of the nematode-feeding sites and the plant-nematode interface with unprecedented resolution quality. This allowed us to obtain detailed measurements of the giant cells’ area in an Arabidopsis line overexpressing CHITINASE-LIKE-1 (CTL1) from optical sections by confocal microscopy, assigning a role for CTL1 and adding essential data to the scarce information of the role of gene repression in giant cells. Furthermore, subcellular structures and features of the nematodes body and tissues from thick organs formed after different biotic interactions, i.e., galls, syncytia, and nodules, were clearly distinguished without embedding or sectioning in different plant species (Arabidopsis, cucumber or Medicago). The combination of this method with molecular studies will be valuable for a better understanding of the plant-biotic interactions. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Genotyping by Sequencing Highlights a Polygenic Resistance to Ralstonia pseudosolanacearum in Eggplant (Solanum melongena L.)
Int. J. Mol. Sci. 2018, 19(2), 357; https://doi.org/10.3390/ijms19020357
Received: 25 December 2017 / Revised: 19 January 2018 / Accepted: 22 January 2018 / Published: 25 January 2018
Cited by 1 | PDF Full-text (1009 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Eggplant cultivation is limited by numerous diseases, including the devastating bacterial wilt (BW) caused by the Ralstonia solanacearum species complex (RSSC). Within the RSSC, Ralstonia pseudosolanacearum (including phylotypes I and III) causes severe damage to all solanaceous crops, including eggplant. Therefore, the creation
[...] Read more.
Eggplant cultivation is limited by numerous diseases, including the devastating bacterial wilt (BW) caused by the Ralstonia solanacearum species complex (RSSC). Within the RSSC, Ralstonia pseudosolanacearum (including phylotypes I and III) causes severe damage to all solanaceous crops, including eggplant. Therefore, the creation of cultivars resistant to R. pseudosolanacearum strains is a major goal for breeders. An intraspecific eggplant population, segregating for resistance, was created from the cross between the susceptible MM738 and the resistant EG203 lines. The population of 123 doubled haploid lines was challenged with two strains belonging to phylotypes I (PSS4) and III (R3598), which both bypass the published EBWR9 BW-resistance quantitative trait locus (QTL). Ten and three QTLs of resistance to PSS4 and to R3598, respectively, were detected and mapped. All were strongly influenced by environmental conditions. The most stable QTLs were found on chromosomes 3 and 6. Given their estimated physical position, these newly detected QTLs are putatively syntenic with BW-resistance QTLs in tomato. In particular, the QTLs’ position on chromosome 6 overlaps with that of the major broad-spectrum tomato resistance QTL Bwr-6. The present study is a first step towards understanding the complex polygenic system, which underlies the high level of BW resistance of the EG203 line. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle The Role of Sugar Transporter Genes during Early Infection by Root-Knot Nematodes
Int. J. Mol. Sci. 2018, 19(1), 302; https://doi.org/10.3390/ijms19010302
Received: 25 December 2017 / Revised: 16 January 2018 / Accepted: 17 January 2018 / Published: 19 January 2018
Cited by 2 | PDF Full-text (3436 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Although pathogens such as nematodes are known to hijack nutrients from host plants, the mechanisms whereby nematodes obtain sugars from plants remain largely unknown. To determine the effects of nematode infection on host plant sugar allocation, soluble sugar (fructose, glucose, sucrose) content was
[...] Read more.
Although pathogens such as nematodes are known to hijack nutrients from host plants, the mechanisms whereby nematodes obtain sugars from plants remain largely unknown. To determine the effects of nematode infection on host plant sugar allocation, soluble sugar (fructose, glucose, sucrose) content was investigated using high-performance liquid chromatography with refractive index detection and was found to increase significantly in tomato (Solanum lycopersicum, Sl) leaves and roots during early infection by root-knot nematodes (RKNs). To further analyze whether sugar transporters played a role in this process, the expression levels of sucrose transporter (SUT/SUC), Sugars Will Eventually be Exported Transporter (SWEET), tonoplast monosaccharide transporter (TMT), and vacuolar glucose transporter (VGT) gene family members were examined by qRT-PCR analysis after RKN infection. The results showed that three SlSUTs, 17 SlSWEETs, three SlTMTs, and SlVGT1 were upregulated in the leaves, whereas three SlSUTs, 17 SlSWEETs, two SlTMTs, and SlVGT1 were induced in the roots. To determine the function of the sugar transporters in the RKN infection process, we examined post-infection responses in the Atsuc2 mutant and pAtSUC2-GUS lines. β-glucuronidase expression was strongly induced at the infection sites, and RKN development was significantly arrested in the Atsuc2 mutant. Taken together, our analyses provide useful information for understanding the sugar transporter responses during early infection by RKNs in tomato. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Overexpression and Down-Regulation of Barley Lipoxygenase LOX2.2 Affects Jasmonate-Regulated Genes and Aphid Fecundity
Int. J. Mol. Sci. 2017, 18(12), 2765; https://doi.org/10.3390/ijms18122765
Received: 2 November 2017 / Revised: 8 December 2017 / Accepted: 15 December 2017 / Published: 19 December 2017
Cited by 3 | PDF Full-text (1234 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Aphids are pests on many crops and depend on plant phloem sap as their food source. In an attempt to find factors improving plant resistance against aphids, we studied the effects of overexpression and down-regulation of the lipoxygenase gene LOX2.2 in barley (
[...] Read more.
Aphids are pests on many crops and depend on plant phloem sap as their food source. In an attempt to find factors improving plant resistance against aphids, we studied the effects of overexpression and down-regulation of the lipoxygenase gene LOX2.2 in barley (Hordeum vulgare L.) on the performance of two aphid species. A specialist, bird cherry-oat aphid (Rhopalosiphum padi L.) and a generalist, green peach aphid (Myzus persicae Sulzer) were studied. LOX2.2 overexpressing lines showed up-regulation of some other jasmonic acid (JA)-regulated genes, and antisense lines showed down-regulation of such genes. Overexpression or suppression of LOX2.2 did not affect aphid settling or the life span on the plants, but in short term fecundity tests, overexpressing plants supported lower aphid numbers and antisense plants higher aphid numbers. The amounts and composition of released volatile organic compounds did not differ between control and LOX2.2 overexpressing lines. Up-regulation of genes was similar for both aphid species. The results suggest that LOX2.2 plays a role in the activation of JA-mediated responses and indicates the involvement of LOX2.2 in basic defense responses. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Overexpression of a New Chitinase Gene EuCHIT2 Enhances Resistance to Erysiphe cichoracearum DC. in Tobacco Plants
Int. J. Mol. Sci. 2017, 18(11), 2361; https://doi.org/10.3390/ijms18112361
Received: 26 September 2017 / Revised: 2 November 2017 / Accepted: 4 November 2017 / Published: 7 November 2017
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Abstract
In this study, we cloned a new chitinase gene, EuCHIT2, from Eucommia ulmoides Oliver (E. ulmoides) using rapid amplification of cDNA ends (RACE) technology and constructed an overexpression vector, pSH-35S-EuCHIT2, to introduce it into tobacco (Nicotiana tabacum
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In this study, we cloned a new chitinase gene, EuCHIT2, from Eucommia ulmoides Oliver (E. ulmoides) using rapid amplification of cDNA ends (RACE) technology and constructed an overexpression vector, pSH-35S-EuCHIT2, to introduce it into tobacco (Nicotiana tabacum cv. Xanthi). Resistance to Erysiphe cichoracearum de Candolle (E.cichoracearum DC) and molecular mechanisms in the transgenic tobacco were determined by drop inoculation, spore counting, determination of physicochemical indicators, and analysis of gene expression. The chitinase activity and resistance to E. cichoracearum DC were significantly higher in the transgenic tobacco than in wild-type tobacco (p < 0.05). The activities of peroxidase (POD) and catalase (CAT), after inoculation with E. cichoracearum DC, were higher in the transgenic tobacco than in the wild-type. Conversely, the malondialdehyde (MDA) content was significantly lower in the transgenic tobacco than the wild-type before and after inoculation. In addition, our study also indicated that the resistance to E. cichoracearum DC might involve the salicylic acid (SA) and jasmonic acid (JA) pathways, because the expression levels of pathogenesis-related gene 1 (PR-1a) and coronatine-insensitive 1 (COI1) were significantly increased and decreased, respectively, after inoculation with E. cichoracearum DC. The present study supports the notion that PR-1a and POD participate in resistance to E. cichoracearum DC in the transgenic tobacco plants. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Investigation of Antimicrobial Peptide Genes Associated with Fungus and Insect Resistance in Maize
Int. J. Mol. Sci. 2017, 18(9), 1938; https://doi.org/10.3390/ijms18091938
Received: 16 August 2017 / Revised: 4 September 2017 / Accepted: 6 September 2017 / Published: 15 September 2017
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Abstract
Antimicrobial peptides (AMPs) are small defense proteins present in various organisms. Major groups of AMPs include beta-barrelin, hevein, knottin, lipid transfer protein (LTP), thionin, defensin, snakin, and cyclotide. Most plant AMPs involve host plant resistance to pathogens such as fungi, viruses, and bacteria,
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Antimicrobial peptides (AMPs) are small defense proteins present in various organisms. Major groups of AMPs include beta-barrelin, hevein, knottin, lipid transfer protein (LTP), thionin, defensin, snakin, and cyclotide. Most plant AMPs involve host plant resistance to pathogens such as fungi, viruses, and bacteria, whereas a few plant AMPs from the cyclotide family carry insecticidal functions. In this research, a genome-wide investigation on antimicrobial peptide genes in maize genome was conducted. AMPs previously identified from various plant species were used as query sequences for maize genome data mining. Thirty-nine new maize AMPs were identified in addition to seven known maize AMPs. Protein sequence analysis revealed 10 distinguishable maize AMP groups. Analysis of mRNA expression of maize AMP genes by quantitative real-time polymerase chain reaction (qRT-PCR) revealed different expression patterns in a panel of 10 maize inbred lines. Five maize AMP genes were found significantly associated with insect or fungus resistance. Identification of maize antimicrobial peptide genes will facilitate the breeding of host plant resistance and improve maize production. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Mapping Quantitative Trait Loci (QTL) for Resistance to Late Blight in Tomato
Int. J. Mol. Sci. 2017, 18(7), 1589; https://doi.org/10.3390/ijms18071589
Received: 6 July 2017 / Revised: 16 July 2017 / Accepted: 19 July 2017 / Published: 22 July 2017
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Abstract
Late blight caused by Phytophthora infestans (Montagne, Bary) is a devastating disease of tomato worldwide. There are three known major genes, Ph-1, Ph-2, and Ph-3, conferring resistance to late blight. In addition to these three genes, it is also believed
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Late blight caused by Phytophthora infestans (Montagne, Bary) is a devastating disease of tomato worldwide. There are three known major genes, Ph-1, Ph-2, and Ph-3, conferring resistance to late blight. In addition to these three genes, it is also believed that there are additional factors or quantitative trait loci (QTL) conferring resistance to late blight. Precise molecular mapping of all those major genes and potential QTL is important in the development of suitable molecular markers and hence, marker-assisted selection (MAS). The objective of the present study was to map the genes and QTL associated with late blight resistance in a tomato population derived from intra-specific crosses. To achieve this objective, a population, derived from the crossings of NC 1CELBR × Fla. 7775, consisting of 250 individuals at F2 and F2-derived families, were evaluated in replicated trials. These were conducted at Mountain Horticultural Crops Reseach & Extension Center (MHCREC) at Mills River, NC, and Mountain Research Staion (MRS) at Waynesville, NC in 2011, 2014, and 2015. There were two major QTL associated with late blight resistance located on chromosomes 9 and 10 with likelihood of odd (LOD) scores of more than 42 and 6, explaining 67% and 14% of the total phenotypic variation, respectively. The major QTLs are probably caused by the Ph-2 and Ph-3 genes. Furthermore, there was a minor QTL on chromosomes 12, which has not been reported before. This minor QTL may be novel and may be worth investigating further. Source of resistance to Ph-2, Ph-3, and this minor QTL traces back to line L3707, or Richter’s Wild Tomato. The combination of major genes and minor QTL may provide a durable resistance to late blight in tomato. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle The Protease Inhibitor CI2c Gene Induced by Bird Cherry-Oat Aphid in Barley Inhibits Green Peach Aphid Fecundity in Transgenic Arabidopsis
Int. J. Mol. Sci. 2017, 18(6), 1317; https://doi.org/10.3390/ijms18061317
Received: 23 May 2017 / Revised: 15 June 2017 / Accepted: 16 June 2017 / Published: 20 June 2017
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Abstract
Aphids are phloem feeders that cause large damage globally as pest insects. They induce a variety of responses in the host plant, but not much is known about which responses are promoting or inhibiting aphid performance. Here, we investigated whether one of the
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Aphids are phloem feeders that cause large damage globally as pest insects. They induce a variety of responses in the host plant, but not much is known about which responses are promoting or inhibiting aphid performance. Here, we investigated whether one of the responses induced in barley by the cereal aphid, bird cherry-oat aphid (Rhopalosiphum padi L.) affects aphid performance in the model plant Arabidopsis thaliana L. A barley cDNA encoding the protease inhibitor CI2c was expressed in A. thaliana and aphid performance was studied using the generalist green peach aphid (Myzus persicae Sulzer). There were no consistent effects on aphid settling or preference or on parameters of life span and long-term fecundity. However, short-term tests with apterous adult aphids showed lower fecundity on three of the transgenic lines, as compared to on control plants. This effect was transient, observed on days 5 to 7, but not later. The results suggest that the protease inhibitor is taken up from the tissue during probing and weakly inhibits fecundity by an unknown mechanism. The study shows that a protease inhibitor induced in barley by an essentially monocot specialist aphid can inhibit a generalist aphid in transgenic Arabidopsis. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessArticle Marker-Assisted Molecular Profiling, Deletion Mutant Analysis, and RNA-Seq Reveal a Disease Resistance Cluster Associated with Uromyces appendiculatus Infection in Common Bean Phaseolus vulgaris L.
Int. J. Mol. Sci. 2017, 18(6), 1109; https://doi.org/10.3390/ijms18061109
Received: 6 March 2017 / Revised: 21 April 2017 / Accepted: 13 May 2017 / Published: 23 May 2017
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Abstract
Common bean (Phaseolus vulgaris L.) is an important legume, useful for its high protein and dietary fiber. The fungal pathogen Uromyces appendiculatus (Pers.) Unger can cause major loss in susceptible varieties of the common bean. The Ur-3 locus provides race specific resistance
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Common bean (Phaseolus vulgaris L.) is an important legume, useful for its high protein and dietary fiber. The fungal pathogen Uromyces appendiculatus (Pers.) Unger can cause major loss in susceptible varieties of the common bean. The Ur-3 locus provides race specific resistance to virulent strains or races of the bean rust pathogen along with Crg, (Complements resistance gene), which is required for Ur-3-mediated rust resistance. In this study, we inoculated two common bean genotypes (resistant “Sierra” and susceptible crg) with rust race 53 of U. appendiculatus, isolated leaf RNA at specific time points, and sequenced their transcriptomes. First, molecular markers were used to locate and identify a 250 kb deletion on chromosome 10 in mutant crg (which carries a deletion at the Crg locus). Next, we identified differential expression of several disease resistance genes between Mock Inoculated (MI) and Inoculated (I) samples of “Sierra” leaf RNA within the 250 kb delineated region. Both marker assisted molecular profiling and RNA-seq were used to identify possible transcriptomic locations of interest regarding the resistance in the common bean to race 53. Identification of differential expression among samples in disease resistance clusters in the bean genome may elucidate significant genes underlying rust resistance. Along with preserving favorable traits in the crop, the current research may also aid in global sustainability of food stocks necessary for many populations. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessReview Regulation and Evolution of NLR Genes: A Close Interconnection for Plant Immunity
Int. J. Mol. Sci. 2018, 19(6), 1662; https://doi.org/10.3390/ijms19061662
Received: 4 May 2018 / Revised: 1 June 2018 / Accepted: 2 June 2018 / Published: 5 June 2018
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Abstract
NLR (NOD-like receptor) genes belong to one of the largest gene families in plants. Their role in plants’ resistance to pathogens has been clearly described for many members of this gene family, and dysregulation or overexpression of some of these genes has been
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NLR (NOD-like receptor) genes belong to one of the largest gene families in plants. Their role in plants’ resistance to pathogens has been clearly described for many members of this gene family, and dysregulation or overexpression of some of these genes has been shown to induce an autoimmunity state that strongly affects plant growth and yield. For this reason, these genes have to be tightly regulated in their expression and activity, and several regulatory mechanisms are described here that tune their gene expression and protein levels. This gene family is subjected to rapid evolution, and to maintain diversity at NLRs, a plethora of genetic mechanisms have been identified as sources of variation. Interestingly, regulation of gene expression and evolution of this gene family are two strictly interconnected aspects. Indeed, some examples have been reported in which mechanisms of gene expression regulation have roles in promotion of the evolution of this gene family. Moreover, co-evolution of the NLR gene family and other gene families devoted to their control has been recently demonstrated, as in the case of miRNAs. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessReview Plant Perception and Short-Term Responses to Phytophagous Insects and Mites
Int. J. Mol. Sci. 2018, 19(5), 1356; https://doi.org/10.3390/ijms19051356
Received: 20 March 2018 / Revised: 19 April 2018 / Accepted: 25 April 2018 / Published: 3 May 2018
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Abstract
Plant–pest relationships involve complex processes encompassing a network of molecules, signals, and regulators for overcoming defenses they develop against each other. Phytophagous arthropods identify plants mainly as a source of food. In turn, plants develop a variety of strategies to avoid damage and
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Plant–pest relationships involve complex processes encompassing a network of molecules, signals, and regulators for overcoming defenses they develop against each other. Phytophagous arthropods identify plants mainly as a source of food. In turn, plants develop a variety of strategies to avoid damage and survive. The success of plant defenses depends on rapid and specific recognition of the phytophagous threat. Subsequently, plants trigger a cascade of short-term responses that eventually result in the production of a wide range of compounds with defense properties. This review deals with the main features involved in the interaction between plants and phytophagous insects and acari, focusing on early responses from the plant side. A general landscape of the diverse strategies employed by plants within the first hours after pest perception to block the capability of phytophagous insects to develop mechanisms of resistance is presented, with the potential of providing alternatives for pest control. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessReview Prospects of Understanding the Molecular Biology of Disease Resistance in Rice
Int. J. Mol. Sci. 2018, 19(4), 1141; https://doi.org/10.3390/ijms19041141
Received: 17 January 2018 / Revised: 3 March 2018 / Accepted: 5 March 2018 / Published: 10 April 2018
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Abstract
Rice is one of the important crops grown worldwide and is considered as an important crop for global food security. Rice is being affected by various fungal, bacterial and viral diseases resulting in huge yield losses every year. Deployment of resistance genes in
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Rice is one of the important crops grown worldwide and is considered as an important crop for global food security. Rice is being affected by various fungal, bacterial and viral diseases resulting in huge yield losses every year. Deployment of resistance genes in various crops is one of the important methods of disease management. However, identification, cloning and characterization of disease resistance genes is a very tedious effort. To increase the life span of resistant cultivars, it is important to understand the molecular basis of plant host–pathogen interaction. With the advancement in rice genetics and genomics, several rice varieties resistant to fungal, bacterial and viral pathogens have been developed. However, resistance response of these varieties break down very frequently because of the emergence of more virulent races of the pathogen in nature. To increase the durability of resistance genes under field conditions, understanding the mechanismof resistance response and its molecular basis should be well understood. Some emerging concepts like interspecies transfer of pattern recognition receptors (PRRs) and transgenerational plant immunitycan be employed to develop sustainable broad spectrum resistant varieties of rice. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessReview Tolerance to Plant Pathogens: Theory and Experimental Evidence
Int. J. Mol. Sci. 2018, 19(3), 810; https://doi.org/10.3390/ijms19030810
Received: 27 January 2018 / Revised: 27 February 2018 / Accepted: 7 March 2018 / Published: 11 March 2018
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Abstract
The two major mechanisms of plant defense against pathogens are resistance (the host’s ability to limit pathogen multiplication) and tolerance (the host’s ability to reduce the effect of infection on its fitness regardless of the level of pathogen multiplication). There is abundant literature
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The two major mechanisms of plant defense against pathogens are resistance (the host’s ability to limit pathogen multiplication) and tolerance (the host’s ability to reduce the effect of infection on its fitness regardless of the level of pathogen multiplication). There is abundant literature on virtually every aspect of plant resistance to pathogens. Although tolerance to plant pathogens is comparatively less understood, studies on this plant defense strategy have led to major insights into its evolution, mechanistic basis and genetic determinants. This review aims at summarizing current theories and experimental evidence on the evolutionary causes and consequences of plant tolerance to pathogens, as well as the existing knowledge on the genetic determinants and mechanisms of tolerance. Our review reveals that (i) in plant-pathogen systems, resistance and tolerance generally coexist, i.e., are not mutually exclusive; (ii) evidence of tolerance polymorphisms is abundant regardless of the pathogen considered; (iii) tolerance is an efficient strategy to reduce the damage on the infected host; and (iv) there is no evidence that tolerance results in increased pathogen multiplication. Taken together, the work discussed in this review indicates that tolerance may be as important as resistance in determining the dynamics of plant-pathogen interactions. Several aspects of plant tolerance to pathogens that still remain unclear and which should be explored in the future, are also outlined. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessReview Ten Prominent Host Proteases in Plant-Pathogen Interactions
Int. J. Mol. Sci. 2018, 19(2), 639; https://doi.org/10.3390/ijms19020639
Received: 2 February 2018 / Revised: 17 February 2018 / Accepted: 17 February 2018 / Published: 24 February 2018
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Abstract
Proteases are enzymes integral to the plant immune system. Multiple aspects of defence are regulated by proteases, including the hypersensitive response, pathogen recognition, priming and peptide hormone release. These processes are regulated by unrelated proteases residing at different subcellular locations. In this review,
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Proteases are enzymes integral to the plant immune system. Multiple aspects of defence are regulated by proteases, including the hypersensitive response, pathogen recognition, priming and peptide hormone release. These processes are regulated by unrelated proteases residing at different subcellular locations. In this review, we discuss 10 prominent plant proteases contributing to the plant immune system, highlighting the diversity of roles they perform in plant defence. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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Open AccessReview Can Plant Defence Mechanisms Provide New Approaches for the Sustainable Control of the Two-Spotted Spider Mite Tetranychus urticae?
Int. J. Mol. Sci. 2018, 19(2), 614; https://doi.org/10.3390/ijms19020614
Received: 28 December 2017 / Revised: 2 February 2018 / Accepted: 18 February 2018 / Published: 21 February 2018
Cited by 2 | PDF Full-text (902 KB) | HTML Full-text | XML Full-text
Abstract
Tetranychus urticae (T. urticae) Koch is a cosmopolitan, polyphagous mite which causes economic losses in both agricultural and ornamental plants. Some traits of T. urticae hamper its management, including a short life cycle, arrhenotokous parthenogenesis, its haplodiploid sex determination system, and
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Tetranychus urticae (T. urticae) Koch is a cosmopolitan, polyphagous mite which causes economic losses in both agricultural and ornamental plants. Some traits of T. urticae hamper its management, including a short life cycle, arrhenotokous parthenogenesis, its haplodiploid sex determination system, and its extraordinary ability to adapt to different hosts and environmental conditions. Currently, the use of chemical and biological control are the major control methods used against this mite. In recent years, some studies have focused on plant defence mechanisms against herbivores. Various families of plant compounds (such as flavonoids, glucosinolates, or acyl sugars) have been shown to behave as acaricides. Plants can be induced upon appropriate stimuli to increase their resistance against spider mites. This knowledge, together with the understanding of mechanisms by which T. urticae detoxifies and adapts to pesticides, may complement the control of this pest. Herein, we describe plant volatile compounds (VOCs) with repellent activity, and new findings about defence priming against spider mites, which interfere with the T. urticae performance. The use of VOCs and defence priming can be integrated into current management practices and reduce the damage caused by T. urticae in the field by implementing new, more sustainable crop management tools. Full article
(This article belongs to the Special Issue Plant Defense Genes Against Biotic Stresses)
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