Open AccessArticle
Characterization of the Genetic Diversity of Acid Lime (Citrus aurantifolia (Christm.) Swingle) Cultivars of Eastern Nepal Using Inter-Simple Sequence Repeat Markers
Plants 2018, 7(2), 46; https://doi.org/10.3390/plants7020046 -
Abstract
Acid lime (Citrus aurantifolia (Christm.) Swingle) is an important fruit crop, which has high commercial value and is cultivated in 60 out of the 77 districts representing all geographical landscapes of Nepal. A lack of improved high-yielding varieties, infestation with various diseases,
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Acid lime (Citrus aurantifolia (Christm.) Swingle) is an important fruit crop, which has high commercial value and is cultivated in 60 out of the 77 districts representing all geographical landscapes of Nepal. A lack of improved high-yielding varieties, infestation with various diseases, and pests, as well as poor management practices might have contributed to its extremely reduced productivity, which necessitates a reliable understanding of genetic diversity in existing cultivars. Hereby, we aim to characterize the genetic diversity of acid lime cultivars cultivated at three different agro-ecological gradients of eastern Nepal, employing PCR-based inter-simple sequence repeat (ISSR) markers. Altogether, 21 polymorphic ISSR markers were used to assess the genetic diversity in 60 acid lime cultivars sampled from different geographical locations. Analysis of binary data matrix was performed on the basis of bands obtained, and principal coordinate analysis and phenogram construction were performed using different computer algorithms. ISSR profiling yielded 234 amplicons, of which 87.18% were polymorphic. The number of amplified fragments ranged from 7–18, with amplicon size ranging from ca. 250–3200 bp. The Numerical Taxonomy and Multivariate System (NTSYS)-based cluster analysis using the unweighted pair group method of arithmetic averages (UPGMA) algorithm and Dice similarity coefficient separated 60 cultivars into two major and three minor clusters. Genetic diversity analysis using Popgene ver. 1.32 revealed the highest percentage of polymorphic bands (PPB), Nei’s genetic diversity (H), and Shannon’s information index (I) for the Terai zone (PPB = 69.66%; H = 0.215; I = 0.325), and the lowest of all three for the high hill zone (PPB = 55.13%; H = 0.173; I = 0.262). Thus, our data indicate that the ISSR marker has been successfully employed for evaluating the genetic diversity of Nepalese acid lime cultivars and has furnished valuable information on intrinsic genetic diversity and the relationship between cultivars that might be useful in acid lime breeding and conservation programs in Nepal. Full article
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Open AccessReview
The Effects of Foliar Sprays with Different Silicon Compounds
Plants 2018, 7(2), 45; https://doi.org/10.3390/plants7020045 -
Abstract
The use of foliar sprays with silicon compounds is relatively new. Initially (in 1990) foliar sprays with silicates were used. In 2003, foliar sprays with (stabilized) silicic acid were introduced, and more recently foliar sprays with silica nanoparticles have also been applied. Foliar
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The use of foliar sprays with silicon compounds is relatively new. Initially (in 1990) foliar sprays with silicates were used. In 2003, foliar sprays with (stabilized) silicic acid were introduced, and more recently foliar sprays with silica nanoparticles have also been applied. Foliar sprays with silicates are effective as pesticides, while (stabilized) silicic acid sprays increase growth and yield and decrease biotic and abiotic stresses. The limited data on foliar silica-nano sprays show a tendency to decrease biotic stress and to stimulate a limited increase in growth and yield. Full article
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Open AccessArticle
Biological Activity of the Salvia officinalis L. (Lamiaceae) Essential Oil on Varroa destructor Infested Honeybees
Plants 2018, 7(2), 44; https://doi.org/10.3390/plants7020044 -
Abstract
The present work is conducted as part of the development and the valorization of bioactive natural substances from Algerian medicinal and aromatic spontaneous plants, a clean alternative method in biological control. For this purpose, the bio-acaricidal activity of Salvia officinalis (sage)essential oil (EO)was
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The present work is conducted as part of the development and the valorization of bioactive natural substances from Algerian medicinal and aromatic spontaneous plants, a clean alternative method in biological control. For this purpose, the bio-acaricidal activity of Salvia officinalis (sage)essential oil (EO)was evaluated against the Varroa destructor, a major threat to the honey bee Apis mellifera ssp. intermissa. The aerial parts of S. officinalis L., 1753 were collected from the Chrea mountainous area in Northern Algeria. They were subjected to hydro distillation by a Clevenger apparatus type to obtain the EO, and screened for bio-acaricidal activity against Varroa destructor by the method of strips impregnated with the mixture EO and twin according to three doses. Pre-treatment results revealed infestation rates in the experimental site ranging from 3.76% to 21.22%. This showed the heterogeneity of infestations in hives according to the density of bees. This constituted a difficulty in monitoring the population dynamics of this parasite. After treatment, a difference in the acaricidal effect of Sage essential oil is noticed. It gives a mortality rate of 6.09% by the dose D1: 5%, 2.32% by the dose D2: 15%, and a low mortality rate of 0.9% by the dose D3: 20%. The chemical treatment carried out by Bayvarol gives a result close to that of the essential oil of Sage (9.97%).These results point to the fact that Sage essential oil treatments have a significant effect and good biological activity with regard to harmful species. Full article
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Open AccessArticle
DNA Barcoding to Confirm the Morphological Identification of the Coral Trees (Erythrina spp., Fabaceae) in the Ancient Gardens of Naples (Campania, Italy)
Plants 2018, 7(2), 43; https://doi.org/10.3390/plants7020043 -
Abstract
The coral trees (genus Erythrina) have been fostering great interest among the botanists and gardeners of Naples, since their arrival in Europe in the second half of the 18th century. Numerous species were present in the royal and private botanical gardens of
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The coral trees (genus Erythrina) have been fostering great interest among the botanists and gardeners of Naples, since their arrival in Europe in the second half of the 18th century. Numerous species were present in the royal and private botanical gardens of the region, but their number has decreased today. The purpose of this work was to verify which species occur nowadays in the public areas of Naples and associate them with the historical information about their introduction. The identification was carried out also by molecular methods, by means of sequencing nuclear and chloroplast DNA markers. The comparison of the sequences obtained for the specimens present in Naples with those present in the literature, together with a morphological examination, allowed us to identify with accuracy the species anciently introduced or nowadays cultivated in Naples. Full article
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Open AccessReview
Exploring the Role of Cell Wall-Related Genes and Polysaccharides during Plant Development
Plants 2018, 7(2), 42; https://doi.org/10.3390/plants7020042 -
Abstract
The majority of organs in plants are not established until after germination, when pluripotent stem cells in the growing apices give rise to daughter cells that proliferate and subsequently differentiate into new tissues and organ primordia. This remarkable capacity is not only restricted
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The majority of organs in plants are not established until after germination, when pluripotent stem cells in the growing apices give rise to daughter cells that proliferate and subsequently differentiate into new tissues and organ primordia. This remarkable capacity is not only restricted to the meristem, since maturing cells in many organs can also rapidly alter their identity depending on the cues they receive. One general feature of plant cell differentiation is a change in cell wall composition at the cell surface. Historically, this has been viewed as a downstream response to primary cues controlling differentiation, but a closer inspection of the wall suggests that it may play a much more active role. Specific polymers within the wall can act as substrates for modifications that impact receptor binding, signal mobility, and cell flexibility. Therefore, far from being a static barrier, the cell wall and its constituent polysaccharides can dictate signal transmission and perception, and directly contribute to a cell’s capacity to differentiate. In this review, we re-visit the role of plant cell wall-related genes and polysaccharides during various stages of development, with a particular focus on how changes in cell wall machinery accompany the exit of cells from the stem cell niche. Full article
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Open AccessArticle
Silicon Influences Soil Availability and Accumulation of Mineral Nutrients in Various Plant Species
Plants 2018, 7(2), 41; https://doi.org/10.3390/plants7020041 -
Abstract
Silicon (Si) effects on mineral nutrient status in plants are not well investigated. It is known that Si has a beneficial effect on plants under stressed conditions. The aim was to make a state of the art investigation of the Si influence: (1)
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Silicon (Si) effects on mineral nutrient status in plants are not well investigated. It is known that Si has a beneficial effect on plants under stressed conditions. The aim was to make a state of the art investigation of the Si influence: (1) on nutrient availability in four different soil types, namely clayish, sandy, alum shale and submerged soil; and (2) on accumulation of various nutrients in maize, lettuce, pea, carrot and wheat growing in hydroponics. Soil was treated with K2SiO3 corresponding to 80 and 1000 kg Si ha−1 and the nutrient medium with 100, 500, 1000 and 5000 μM Si. In general, Si effects were similar in all analyzed plant species and in all soil types tested. Results showed that, in soil, Si increased the availability of Ca, P, S, Mn, Zn, Cu and Mo and that of Cl and Fe tended to increase. The availability of K and Mg was not much affected by Si. Uptake from solution of S, Mg, Ca, B, Fe, and Mn increased; N, Cu, Zn and K decreased; P decreased/increased; and Cl and Mo was not influenced. Translocation to shoot of Mg, Ca, S, Mn, and Mo increased; Fe, Cu and Zn decreased; and K, P, N, Cl and B was not affected. It was concluded that, if plants had been cultivated in soil, Si-maintained increased availability of nutrients in the soil solution would probably compensate for the decrease in tissue concentration of those nutrient elements. The study shows that Si also influences the nutrient uptake in non-stressed plants. Full article
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Open AccessArticle
Allelopathic Responses of Rice Seedlings under Some Different Stresses
Plants 2018, 7(2), 40; https://doi.org/10.3390/plants7020040 -
Abstract
The objective of this study was to evaluate the allelopathic responses of rice seedlings under submergence stress at different temperatures (10, 25, 32, and 37 °C). The results showed that a wide range of allelopathic responses of rice seedlings depended on varieties and
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The objective of this study was to evaluate the allelopathic responses of rice seedlings under submergence stress at different temperatures (10, 25, 32, and 37 °C). The results showed that a wide range of allelopathic responses of rice seedlings depended on varieties and stress conditions, with temperature was being a key factor. It showed that the extracts of rice seedlings induced significant suppression on lettuce and radish seedling germination, but had negligible allelopathic effects on growth of barnyardgrass, whilst the emergence and growth of natural weeds was stimulated. In contrast, the root exudates of Koshihikari rice seedlings (K32) at 32 °C reduced the number of total weeds by ≈60.0% and the total dry weight of weeds by 93.0%; i.e., to a greater extent than other root exudates. Among the 13 identified phenolic acids, p-hydroxybenzoic, vanillic, syringic, sinapic and benzoic acids—at concentrations of 0.360, 0.045, 3.052, 1.309 and 5.543 μg/mL might be involved in allelopathic responses of K32, inhibiting the growth of barnyardgrass and natural weeds. Findings of the present study may provide useful information on allelopathic responses of rice under environmental stresses and thus further understand of the competitive relationships between rice and weeds under natural conditions. Full article
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Open AccessArticle
Phenotypic and Physiological Evaluation of Two and Six Rows Barley under Different Environmental Conditions
Plants 2018, 7(2), 39; https://doi.org/10.3390/plants7020039 -
Abstract
In recent years, barley has attracted more interest as a food and feed source because of its high soluble dietary fiber and β-glucan content compared with other small grains. Twenty-five barley genotypes (20 imported genotypes and five check cultivars) were grown in three
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In recent years, barley has attracted more interest as a food and feed source because of its high soluble dietary fiber and β-glucan content compared with other small grains. Twenty-five barley genotypes (20 imported genotypes and five check cultivars) were grown in three environments for two successive seasons: 2015/2016 and 2016/2017. The first environment was in El-Nubaria, Alexandria, Egypt during 2015/2016, while the second and third environments were in El-Bostan, Elbhera, Egypt during 2015/2016 and 2016/2017. The experiments were conducted in a randomized complete block design with the three replicates. The primary objectives of the current study were to evaluate the performance of 20 imported barley genotypes under several environmental conditions. The imported materials were superior to the local commercial cultivars for several traits, including grain yield. Therefore, the superior genotypes will be further evaluated and used in barley breeding programs. Our future work will focus on creating several crosses among the selected superior genotypes to improve yield and other important traits, while applying marker-assisted selection. Full article
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Open AccessCommunication
Examination of S-Locus Regulated Differential Expression in Primula vulgaris Floral Development
Plants 2018, 7(2), 38; https://doi.org/10.3390/plants7020038 -
Abstract
Recent findings on the molecular basis of heteromorphic self-incompatibility in Primula have shown that the controlling self-incompatibility (S)-locus is not allelic, but is instead a small hemizygous region of only a few genes in the thrum genotype. How these genes alter
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Recent findings on the molecular basis of heteromorphic self-incompatibility in Primula have shown that the controlling self-incompatibility (S)-locus is not allelic, but is instead a small hemizygous region of only a few genes in the thrum genotype. How these genes alter the development of floral morphology and the specificity of self-incompatibility is still not completely clear. In order to start to identify genes regulated by the S-locus and elucidate the large-scale biological processes affected, we used RNA-seq data from floral buds of heteromorphic P. vulgaris pin (long style, short anthers) and thrum (short style, long anthers) morphs at early and late developmental time points. Differential expression between the two morphs was assessed at both time points and Gene Ontology term analyses of these gene sets were conducted. Our findings suggest that the S-locus regulates a large number of genes outside its physical bounds and likely sets up a cascade of expression changes. Additionally, we found evidence to suggest that there may be a timing difference in pollen development between the morphs, with pin pollen development proceeding earlier than thrum pollen development. This finding provides insight into how morphological differences in pollen between the morphs may be established, but intriguingly, could also be related to the self-incompatibility phenotype. Full article
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Open AccessArticle
Assessment of Sulfur Deficiency under Field Conditions by Single Measurements of Sulfur, Chloride and Phosphorus in Mature Leaves
Plants 2018, 7(2), 37; https://doi.org/10.3390/plants7020037 -
Abstract
Determination of S status is very important to detect S deficiency and prevent losses of yield and seed quality. The aim of this study was to investigate the possibility of using the ([Cl]+[NO3]+[PO43−]):[SO42−
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Determination of S status is very important to detect S deficiency and prevent losses of yield and seed quality. The aim of this study was to investigate the possibility of using the ([Cl]+[NO3]+[PO43−]):[SO42−] ratio as an indicator of S nutrition under field conditions in Brassica napus and whether this could be applied to other species. Different S and nitrogen (N) fertilizations were applied on a S deficient field of oilseed rape to harvest mature leaves and analyze their anion and element contents in order to evaluate a new S nutrition indicator and useful threshold values. Large sets of commercial varieties were then used to test S deficiency scenarios. As main results, this study shown that, under field conditions, leaf ([Cl]+[NO3]+[PO43−]):[SO42−] ratio was increased by lowering S fertilization, indicating S deficiency. The usefulness of this ratio was also found for other species grown under controlled conditions and it could be simplified by using the elemental ([Cl]+[P]):[S] ratio. Threshold values were determined and used for the clustering of commercial varieties within three groups: S deficient, at risk of S deficiency and S sufficient. The ([Cl]+[P]):[S] ratio quantified under field conditions, can be used as an early and accurate diagnostic tool to manage S fertilization. Full article
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Open AccessArticle
Treatment of Anaerobic Digester Effluent Using Acorus calamus: Effects on Plant Growth and Tissue Composition
Plants 2018, 7(2), 36; https://doi.org/10.3390/plants7020036 -
Abstract
The responses of Acorus calamus under greenhouse conditions for 56 days when exposed to three dilutions (25%, 50%, and undiluted) of anaerobic digester effluent from a swine farm were determined. Plant growth, morphology, pigments, and minerals in plant tissues as well as water
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The responses of Acorus calamus under greenhouse conditions for 56 days when exposed to three dilutions (25%, 50%, and undiluted) of anaerobic digester effluent from a swine farm were determined. Plant growth, morphology, pigments, and minerals in plant tissues as well as water quality were investigated. The plants grew well in all concentrations of anaerobic digester effluent with no statistically significant effects on plant growth and morphology, and without any toxicity symptoms. The NH4+ concentrations in leaves and roots and the NO3 concentrations in leaves as well as the nitrogen, phosphorus, and potassium concentrations in the plant tissues increased with increasing effluent concentration. The nutrients in the anaerobic digester effluent were removed effectively (NH4-N > 99% removal; PO4-P > 80% removal), with highest removal rates in the undiluted digester effluent. The removal of total suspended solids (>80% in 42 days) and chemical oxygen demand (37–53%) were lower. The dissolved oxygen concentration in the anaerobic digester effluent increased overtime, probably because of root oxygen release. It is concluded that Acorus calamus could be a promising species for treating high-strength wastewater with high nutrient concentrations, such as effluents from anaerobic digesters as well as other types of agricultural wastewaters. Full article
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Open AccessArticle
Seed Dormancy Involves a Transcriptional Program That Supports Early Plastid Functionality during Imbibition
Plants 2018, 7(2), 35; https://doi.org/10.3390/plants7020035 -
Abstract
Red rice fully dormant seeds do not germinate even under favorable germination conditions. In several species, including rice, seed dormancy can be removed by dry-afterripening (warm storage); thus, dormant and non-dormant seeds can be compared for the same genotype. A weedy (red) rice
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Red rice fully dormant seeds do not germinate even under favorable germination conditions. In several species, including rice, seed dormancy can be removed by dry-afterripening (warm storage); thus, dormant and non-dormant seeds can be compared for the same genotype. A weedy (red) rice genotype with strong dormancy was used for mRNA expression profiling, by RNA-Seq, of dormant and non-dormant dehulled caryopses (here addressed as seeds) at two temperatures (30 °C and 10 °C) and two durations of incubation in water (8 h and 8 days). Aim of the study was to highlight the differences in the transcriptome of dormant and non-dormant imbibed seeds. Transcript data suggested important differences between these seeds (at least, as inferred by expression-based metabolism reconstruction): dry-afterripening seems to impose a respiratory impairment onto non-dormant seeds, thus glycolysis is deduced to be preferentially directed to alcoholic fermentation in non-dormant seeds but to alanine production in dormant ones; phosphoenolpyruvate carboxykinase, pyruvate phosphate dikinase and alanine aminotransferase pathways appear to have an important gluconeogenetic role associated with the restoration of plastid functions in the dormant seed following imbibition; correspondingly, co-expression analysis pointed out a commitment to guarantee plastid functionality in dormant seeds. At 8 h of imbibition, as inferred by gene expression, dormant seeds appear to preferentially use carbon and nitrogen resources for biosynthetic processes in the plastid, including starch and proanthocyanidins accumulation. Chromatin modification appears to be a possible mechanism involved in the transition from dormancy to germination. Non-dormant seeds show higher expression of genes related to cell wall modification, suggesting they prepare for acrospire/radicle elongation. Full article
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Open AccessCommunication
TUNEL Assay and DAPI Staining Revealed Few Alterations of Cellular Morphology in Naturally and Artificially Aged Seeds of Cultivated Flax
Plants 2018, 7(2), 34; https://doi.org/10.3390/plants7020034 -
Abstract
In a search for useful seed aging signals as biomarkers for seed viability prediction, we conducted an experiment using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and 4′,6-diamidino-2-phenylindole (DAPI) staining to analyze morphological and molecular changes in naturally aged (NA)
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In a search for useful seed aging signals as biomarkers for seed viability prediction, we conducted an experiment using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and 4′,6-diamidino-2-phenylindole (DAPI) staining to analyze morphological and molecular changes in naturally aged (NA) and artificially aged (AA) flax (Linum usitatissimum L.) seeds. A total of 2546 sections were performed from 112 seeds of 12 NA and AA seed samples with variable germination rates. Analyzing 1384 micrographs generated from TUNEL assay and DAPI staining revealed few alterations of the cellular morphology of the NA and AA seeds. Also, the revealed DNA degradations in the aged flax seeds appeared to be associated with seed samples of low germination rates. These results suggest that oily flax seed aging may alter the cellular morphology differently than starchy wheat seed aging. The results also imply that the TUNEL assay and DAPI staining may not yield informative assessments on cellular alterations and DNA degradation after the aging of oily seeds. Full article
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Open AccessReview
Silicon and Mechanisms of Plant Resistance to Insect Pests
Plants 2018, 7(2), 33; https://doi.org/10.3390/plants7020033 -
Abstract
This paper reviews the most recent progress in exploring silicon-mediated resistance to herbivorous insects and the mechanisms involved. The aim is to determine whether any mechanism seems more common than the others as well as whether the mechanisms are more pronounced in silicon-accumulating
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This paper reviews the most recent progress in exploring silicon-mediated resistance to herbivorous insects and the mechanisms involved. The aim is to determine whether any mechanism seems more common than the others as well as whether the mechanisms are more pronounced in silicon-accumulating than non-silicon-accumulating species or in monocots than eudicots. Two types of mechanisms counter insect pest attacks: physical or mechanical barriers and biochemical/molecular mechanisms (in which Si can upregulate and prime plant defence pathways against insects). Although most studies have examined high Si accumulators, both accumulators and non-accumulators of silicon as well as monocots and eudicots display similar Si defence mechanisms against insects. Full article
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Open AccessArticle
Transcriptome and Metabolome Analyses Reveal That Nitrate Strongly Promotes Nitrogen and Carbon Metabolism in Soybean Roots, but Tends to Repress It in Nodules
Plants 2018, 7(2), 32; https://doi.org/10.3390/plants7020032 -
Abstract
Leguminous plants form root nodules with rhizobia that fix atmospheric dinitrogen (N2) for the nitrogen (N) nutrient. Combined nitrogen sources, particular nitrate, severely repress nodule growth and nitrogen fixation activity in soybeans (Glycine max [L.] Merr.). A microarray-based transcriptome analysis
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Leguminous plants form root nodules with rhizobia that fix atmospheric dinitrogen (N2) for the nitrogen (N) nutrient. Combined nitrogen sources, particular nitrate, severely repress nodule growth and nitrogen fixation activity in soybeans (Glycine max [L.] Merr.). A microarray-based transcriptome analysis and the metabolome analysis were carried out for the roots and nodules of hydroponically grown soybean plants treated with 5 mM of nitrate for 24 h and compared with control without nitrate. Gene expression ratios of nitrate vs. the control were highly enhanced for those probesets related to nitrate transport and assimilation and carbon metabolism in the roots, but much less so in the nodules, except for the nitrate transport and asparagine synthetase. From the metabolome analysis, the concentration ratios of metabolites for the nitrate treatment vs. the control indicated that most of the amino acids, phosphorous-compounds and organic acids in roots were increased about twofold in the roots, whereas in the nodules most of the concentrations of the amino acids, P-compounds and organic acids were decreased while asparagine increased exceptionally. These results may support the hypothesis that nitrate primarily promotes nitrogen and carbon metabolism in the roots, but mainly represses this metabolism in the nodules. Full article
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Open AccessArticle
Separation, Identification, and Antidiabetic Activity of Catechin Isolated from Arbutus unedo L. Plant Roots
Plants 2018, 7(2), 31; https://doi.org/10.3390/plants7020031 -
Abstract
Phytopharmaceuticals play an essential role in medicine, since the need to investigate highly effective and safe drugs for the treatment of diabetes mellitus disease remains a significant challenge for modern medicine. Arbutus unedo L. root has various therapeutic properties, and has been used
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Phytopharmaceuticals play an essential role in medicine, since the need to investigate highly effective and safe drugs for the treatment of diabetes mellitus disease remains a significant challenge for modern medicine. Arbutus unedo L. root has various therapeutic properties, and has been used widely in the traditional medicine as an antidiabetic agent. The current study aimed to isolate the pharmacologically active compound from A. unedo roots using accelerated solvent extraction technology, to determine its chemical structure using different instrumental analytical methods, and also to evaluate the α-glucosidase inhibitory activity. The roots of A. unedo were exhaustively extracted by high-pressure static extraction using the Zippertex® technology (Dionex-ASE, Paris, France), and the extract was mixed with XAD-16 resin to reach quantifiable amounts of active compounds which were identified by high-pressure liquid chromatography (HPLC), 1H NMR (300 MHz), and 13C NMR. The antidiabetic activity of the isolated compound was evaluated using the α-glucosidase inhibitory assay. The active compound was isolated, and its structure was identified as catechin using instrumental analysis.The results revealed that the isolated compound has potential α-glucosidase inhibitory activity with an IC50 value of 87.55 ± 2.23 μg/mL greater than acarbose. This was used as a positive control, which has an IC50 value of 199.53 ± 1.12 μg/mL. According to the results achieved, the roots of A. unedo were considered the best source of catechin and the Zippertex® technology method of extraction is the best method for isolation of this therapeutic active compound. In addition, the α-glucosidase inhibitory activity results confirmed the traditional use of A. unedo roots as an antidiabetic agent. Future clinical trials and investigations of antidiabetic and other pharmacological effects such as anticancer are required. Full article
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Open AccessEditorial
Flavonoid Functions in Plants and Their Interactions with Other Organisms
Plants 2018, 7(2), 30; https://doi.org/10.3390/plants7020030 -
Abstract
Flavonoids are structurally diverse secondary metabolites in plants, with a multitude of functions. These span from functions in regulating plant development, pigmentation, and UV protection, to an array of roles in defence and signalling between plants and microorganisms. Because of their prevalence in
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Flavonoids are structurally diverse secondary metabolites in plants, with a multitude of functions. These span from functions in regulating plant development, pigmentation, and UV protection, to an array of roles in defence and signalling between plants and microorganisms. Because of their prevalence in the human diet, many flavonoids constitute important components of medicinal plants and are used in the control of inflammation and cancer prevention. Advances in the elucidation of flavonoid biosynthesis and its regulation have led to an increasing number of studies aimed at engineering the flavonoid pathway for enhancing nutritional value and plant defences against pathogens and herbivores, as well as modifying the feeding value of pastures. Many future opportunities await for the exploitation of this colourful pathway in crops, pastures, and medicinal plants. Full article
Open AccessArticle
Effect of Silicon on the Tolerance of Wheat (Triticum aestivum L.) to Salt Stress at Different Growth Stages: Case Study for the Management of Irrigation Water
Plants 2018, 7(2), 29; https://doi.org/10.3390/plants7020029 -
Abstract
This paper aims to determine the most tolerant growth stage(s) of wheat to salinity stress with the addition of silicon. The aim was to investigate whether saline water could be used instead of good quality water for irrigation without implicating a greater risk
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This paper aims to determine the most tolerant growth stage(s) of wheat to salinity stress with the addition of silicon. The aim was to investigate whether saline water could be used instead of good quality water for irrigation without implicating a greater risk to crop production. Local wheat cv. Gimmiza 11 was germinated and grown in sand cultures. Four different NaCl salinity levels were used as treatments: 0, 60, 90 and 120 mM. This was in the presence of 0 and 0.78 mM Si which added as sodium meta- silicate (Na2SiO3·9H2O). Both the NaCl and Si treatments were carried out using a full strength nutrient solution that was adjusted at pH 6.0 and used for irrigation in four replications. The application of Si with the saline nutrient media significantly enhanced superoxide dismutase (SOD) and catalase (CAT) activities in plant leaves at the booting stage compared to the other stages. This was associated with a marked decline in the H2O2 content. At the booting stage, the Si treatment promoted CAT activity in 120 mM NaCl-stressed leaves compared to the leaves treated with only 120 mM NaCl solution. SOD showed greater prevalence at the booting stage when Si was added into the saline media, and it also revealed maximum activity at the milky stage with salinity stress. This was associated with a smaller reduction in shoot fresh and dry weights, greater reduction in the leaf Na+ content and an increase in the K+ content, which ultimately increased the cytosolic K+/Na+ ratio. Chlorophyll a and b and carotenoid (total photosynthetic pigments) were also higher at the booting stage of salt-stressed plants treated with Si compared to other stages. Accordingly, Si application enhanced the salt tolerance of wheat and reduced the inhibitory effect of Na+ and oxidative stress damage as growth proceeded towards maturity, particularly at the booting stage. This shows that saline water can be used for wheat irrigation at the booting stage (much water is consumed) when good quality water is not available for supplemental irrigation. A field study is needed to confirm the greenhouse results. Full article
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Open AccessArticle
Effects of Drought on Nutrient Uptake and the Levels of Nutrient-Uptake Proteins in Roots of Drought-Sensitive and -Tolerant Grasses
Plants 2018, 7(2), 28; https://doi.org/10.3390/plants7020028 -
Abstract
Climate change will increase drought in many regions of the world. Besides decreasing productivity, drought also decreases the concentration (%) of nitrogen (N) and phosphorous (P) in plants. We investigated if decreases in nutrient status during drought are correlated with decreases in levels
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Climate change will increase drought in many regions of the world. Besides decreasing productivity, drought also decreases the concentration (%) of nitrogen (N) and phosphorous (P) in plants. We investigated if decreases in nutrient status during drought are correlated with decreases in levels of nutrient-uptake proteins in roots, which has not been quantified. Drought-sensitive (Hordeum vulgare, Zea mays) and -tolerant grasses (Andropogon gerardii) were harvested at mid and late drought, when we measured biomass, plant %N and P, root N- and P-uptake rates, and concentrations of major nutrient-uptake proteins in roots (NRT1 for NO3, AMT1 for NH4, and PHT1 for P). Drought reduced %N and P, indicating that it reduced nutrient acquisition more than growth. Decreases in P uptake with drought were correlated with decreases in both concentration and activity of P-uptake proteins, but decreases in N uptake were weakly correlated with levels of N-uptake proteins. Nutrient-uptake proteins per gram root decreased despite increases per gram total protein, because of the larger decreases in total protein per gram. Thus, drought-related decreases in nutrient concentration, especially %P, were likely caused, at least partly, by decreases in the concentration of root nutrient-uptake proteins in both drought-sensitive and -tolerant species. Full article
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Open AccessArticle
Identification of Leaf Promoters for Use in Transgenic Wheat
Plants 2018, 7(2), 27; https://doi.org/10.3390/plants7020027 -
Abstract
Wheat yields have plateaued in recent years and given the growing global population there is a pressing need to develop higher yielding varieties to meet future demand. Genetic manipulation of photosynthesis in elite wheat varieties offers the opportunity to significantly increase yields. However,
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Wheat yields have plateaued in recent years and given the growing global population there is a pressing need to develop higher yielding varieties to meet future demand. Genetic manipulation of photosynthesis in elite wheat varieties offers the opportunity to significantly increase yields. However, the absence of a well-defined molecular tool-box of promoters to manipulate leaf processes in wheat hinders advancements in this area. Two promoters, one driving the expression of sedoheptulose-1,7-bisphosphatase (SBPase) and the other fructose-1,6-bisphosphate aldolase (FBPA) from Brachypodium distachyon were identified and cloned into a vector in front of the GUS reporter gene. Both promoters were shown to be functionally active in wheat in both transient assays and in stably transformed wheat plants. Analysis of the stable transformants of wheat (cv. Cadenza) showed that both promoters controlled gus expression throughout leaf development as well as in other green tissues. The availability of these promoters provides new tools for the expression of genes in transgenic wheat leaves and also paves the way for multigene manipulation of photosynthesis to improve yields. Full article
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