In situ self-induced electrical stimulation to plants: Modulates morphogenesis, photosynthesis and gene expression in Vigna radiata and Cicer arietinum.

Specific stimuli to plants influence intracellular and intercellular communications, activation of ion channels, gene expression, growth and development. The functional role of self-induced in situ electrical stimuli at the rhizosphere of the plant by placing electrode assembly in a defined circuit mode was studied on the growth and development of Vigna radiata and Cicer arietinum plants. Experiments were designed with three-circuit mode configurational variations (CC-P, OC-P and SC-P) and compared with the relative performance of control system (non-potential). The plants cultivated under the in situ electrical stimuli (low-current) showed a marked influence on growth and photosynthetic performance of the plants. CC-P operation showed improved vegetative growth, characterized by increased roots, shoots and biomass along with accelerated plant growth from seed germination to vegetation, flowering and pod formation leading towards earlier and more robust flowering compared to control system. Plants also showed higher aquaporin gene expression levels in CC-P operation. The control operation showed 10 days additional maturation time compared to CC-P operation. The strategy can be beneficially applied to augment the bioremediation capacity of complex pollutants with reference to phytoremediation or constructed wetland systems where the plant and its roots are the main enabler apart from agriculture applications specific to nursery-raised or transplanted plants.

Differences in foliar phosphorus fractions, rather than in cell-specific phosphorus allocation, underlie contrasting photosynthetic phosphorus use efficiency among chickpea genotypes.

Although significant intraspecific variation in photosynthetic phosphorus (P) use efficiency (PPUE) has been shown in numerous species, we still know little about the biochemical basis for differences in PPUE among genotypes within a species. Here, we grew two high PPUE and two low PPUE chickpea (Cicer arietinum) genotypes with low P supply in a glasshouse to compare their photosynthesis-related traits, total foliar P concentration ([P]) and chemical P fractions (i.e. inorganic P (Pi), metabolite P, lipid P, nucleic acid P, and residual P). Foliar cell-specific nutrient concentrations including P were characterized using elemental X-ray microanalysis. Genotypes with high PPUE showed lower total foliar [P] without slower photosynthetic rates. No consistent differences in cellular [P] between the epidermis and mesophyll cells occurred across the four genotypes. In contrast, high PPUE was associated with lower allocation to Pi and metabolite P, with PPUE being negatively correlated with the percentage of these two fractions. Furthermore, a lower allocation to Pi and metabolite P was correlated with a greater allocation to nucleic acid P, but not to lipid P. Collectively, our results suggest that a different allocation to foliar P fractions, rather than preferential P allocation to specific leaf tissues, underlies the contrasting PPUE among chickpea genotypes.

Evaluation of chickpea protein isolate as a partial replacement for phosphate in pork meat batters: Techno-functional properties and molecular characteristic modifications.

The effects of chickpea protein isolate (CPI, 0.5-2 %, w/w) on the techno-functional properties of 50 % reduced-phosphate pork meat batters (RPMBs) were explored. The results showed that 1.5-2 % CPI significantly decreased the cooking loss but significantly increased the emulsion stability, hardness, gumminess, chewiness and yellowness (b*) of RPMBs (P < 0.05). CPI altered molecular characteristics of RPMBs, as demonstrated by the increased storage modulus (G'), the conversion of free water into immobilized water, the reduced intensities of the aliphatic residue Raman bands, the decreased α-helical structure and the formation of well-organized gel networks with evenly distributed small fat globules. Principal component analysis and Pearson's correlation analysis indicated that CPI-induced changes in RPMB techno-functional properties were closely related to molecular characteristics. Hierarchical cluster analysis suggested that RPMBs supplemented with 1.5-2 % CPI were highly similar in techno-functional properties to the high-phosphate group. Therefore, CPI may potentially be used to develop reduced-phosphate meat products.

Potential role of rhizobia to enhance chickpea-growth and yield in low fertility-soils of Tunisia.

Plant growth-promoting rhizobacteria are bacteria that improve plant growth and reduce plant pathogen damages. In this study, 100 nodule bacteria were isolated from chickpea, screened for their plant growth-promoting (PGP) traits and then characterised by PCR-RFLP of 16 S rDNA. Results showed that most of the slow-growing isolates fixed nitrogen but those exhibiting fast-growth did not. Fourteen isolates solubilized inorganic phosphorus, 16 strains produced siderophores, and 17 strains produced indole acetic acid. Co-culture experiments identified three strains having an inhibitory effect against Fusarium oxysporum, the primary pathogenic fungus for chickpea in Tunisia. Rhizobia with PGP traits were assigned to Mesorhizobium ciceri, Mesorhizobium mediterraneum, Sinorhizobium meliloti and Agrobacterium tumefaciens. We noted that PGP activities were differentially distributed between M. ciceri and M. mediterraneum. The region of Mateur in northern Tunisia, with clay-silty soil, was the origin of 53% of PGP isolates. Interestingly, we found that S. meliloti and A. tumefaciens strains did not behave as parasitic nodule-bacteria but as PGP rhizobacteria useful for chickpea nutrition and health. In fact, S. meliloti strains could solubilize phosphorus, produce siderophore and auxin. The A. tumefaciens strains could perform the previous PGP traits and inhibit pathogen growth also. Finally, one candidate strain of M. ciceri (LL10)-selected for its highest symbiotic nitrogen fixation and phosphorus solubilization-was used for field experiment. The LL10 inoculation increased grain yield more than three-fold. These finding showed the potential role of rhizobia to be used as biofertilizers and biopesticides, representing low-cost and environment-friendly inputs for sustainable agriculture.

Impact of phosphorous-deficit conditions on morpho-physiological traits and phosphorous metabolism in chickpea genotypes.

Chickpea, an important food legume, is primarily grown on marginal soils with low soil fertility. Although chickpea can fix N, soil phosphorus (P) deficiency in crop growing areas is a major limiting factor for chickpea production. This study was undertaken to evaluate twenty-five chickpea cultivars for morpho-physiological traits and yield under low and normal phosphorous conditions. Based on morpho-physiological traits such as length and area of roots and shoots, root length density, root and shoot biomass, chlorophyll content, number of nodules and root tips, tolerance indices and yield, these cultivars were characterised into susceptible (ICC67, ICC1915, ICC2593, ICC5337, ICC5879, ICC8950, ICC13441, ICC1483, ICC15606 and ICC15888), tolerant (ICC10755, IG72070, ICCV97105, ICCV2, ICCV92809, ICCV92337 and ICCV95423) and the remaining cultivars were moderately tolerant to phosphorous-deficit conditions. Higher activities of enzymes of phosphorous metabolism such as acid phosphatase and phytase in roots and nodules of tolerant chickpea cultivars (ICCV97105, ICCV92337, ICCV95423) as compared to susceptible cultivars (ICC67, ICC15606, ICC15888) at different developmental stages might be attributing to their better performance for growth parameters and productivity traits under phosphorous-deficit conditions.

Characterization of peptides with antioxidant activity and antidiabetic potential obtained from chickpea (Cicer arietinum L.) protein hydrolyzates.

Alcalase hydrolyzates were prepared from the albumin (AH) and globulin (GH) fractions of eight chickpea (Cicer arietinum L.) genotypes from Mexico and 10 from other countries. Protein content, antioxidant activity (AA) (ABTS, DPPH), and degree of hydrolysis were evaluated and the best genotype was selected by principal component analysis. The hydrolyzates of the chosen genotype were analyzed for its antidiabetic potential measured as inhibition of α-amylase, α-glucosidase, and dipeptidyl peptidase-4 (DPP4). Peptide profiles were obtained by liquid chromatography-mass spectrometry (UPLC-DAD-MS), and the most active peptides were analyzed by molecular docking. The average antioxidant activity of albumin hydrolyzates was higher than that of globulin hydrolyzates. ICC3761 was the selected genotype and peptides purified from the albumin hydrolyzate showed the best antioxidant activity and antidiabetic potential (FEI, FEL, FIE, FKN, FGKG, and MEE). FEI, FEL, and FIE were in the same chromatographic peak and this mixture showed the best ABTS scavenging (78.25%) and DPP4 inhibition (IC50  = 4.20 µg/ml). MEE showed the best DPPH scavenging (47%). FGKG showed the best inhibition of α-amylase (54%) and α-glucosidase (56%) and may be a competitive inhibitor based on in silico-predicted interactions with catalytic amino acids in the active site of both enzymes. These peptides could be used as nutraceutical supplements against diseases related to oxidative stress and diabetes. PRACTICAL APPLICATION: This study showed that chickpea protein hydrolyzates are good sources of peptides with antidiabetic potential, showing high antioxidant activity and inhibition of enzymes related to carbohydrate metabolism and type 2 diabetes. These hydrolyzates could be formulated in functional foods for diabetes.

Calcium and ethylene glycol tetraacetic acid mitigate toxicity and alteration of gene expression associated with cadmium stress in chickpea (Cicer arietinum L.) shoots.

In the aim to estimate the protective role of calcium (Ca) and ethylene glycol tetraacetic acid (EGTA) against cadmium (Cd)-induced damage, chickpea (Cicer arietinum L.) seeds were exposed to 200 µM Cd stress for 6 days or 3 days then subjected to co-treatment of the metal with either 100 mM CaCl2 or 100 µM EGTA for 3 additional days. The addition of Ca and EGTA improved seedling growth. This protecting effect was correlated to the alleviation of the metal-induced oxidative stress, exemplified by the reduction of hydrogen peroxide (H2O2) contents. Besides, Ca and EGTA stimulated thioredoxin (Trx) and thioredoxin reductase (NTR) activities (2.75- and 1.75-fold increase when compared to Cd-stressed, respectively) protecting, thereby, protein -SH groups from the Cd-mediated oxidation, and modulated ferredoxin (Fdx) activity to a control level. Moreover, Ca and EGTA reinstated the glutathione redox steady state, mainly via preserving a high level of glutathione reduced form (GSH). This effect coincided with the maintaining of the Cd-stimulated glutathione reductase (GR) activity and the decline of glutathione peroxidase (GPX, 43% lower than Cd-stressed shoots) activity. Ca and EGTA counteracted the inhibitory effect of Cd on the activity and gene expression of Cu/Zn-superoxide dismutase (Cu/Zn-SOD) isoenzyme and modulated the activities of catalase (CAT) and ascorbate peroxidase (APX). Overall, our results provided evidence that Ca and EGTA supplement could be a promising approach in the remediation of Cd-contaminated environment.

Characterization of chickpea genotypes of Pakistani origin for genetic diversity and zinc grain biofortification.

BACKGROUND: Intake of food low in essential minerals, like zinc (Zn), is one of the major reasons of malnutrition. Development of genotypes with grains enriched in essential minerals may help to solve the issue of malnutrition. In this study, 16 chickpea genotypes (eight each of desi and kabuli types) of Pakistani origin were evaluated for genetic diversity and grain Zn biofortification potential with and without Zn fertilization. RESULTS: A wide variation was noted for agronomic, physiological, agro-physiological, utilization, and apparent recovery efficiencies of Zn in the chickpea genotypes tested. Genotypes also differed for grain Zn concentration (37.5-48.6 mg kg-1 ), bioavailable Zn (3.72-4.42 mg day-1 ), and grain yield. The highest grain Zn concentration and bioavailable Zn were noted in genotypes NIAB-CH-2016 (47.1 mg kg-1 and 4.30 mg day-1 respectively) and Noor-2013 (48.6 mg kg-1 and 4.38 mg day-1 respectively) among the desi and kabuli types respectively. The same genotypes were the highest yielders. Cluster analysis showed that all (eight) kabuli genotypes grouped together, whereas most (six) of the desi genotypes clustered in a separate group. There was low to moderate genetic diversity (0.149 for desi and 0.104 for kabuli types) and a low level of genetic differentiation between the two chickpea types (0.098). CONCLUSION: Two populations of chickpea had low to moderate genetic diversity, with consistent gene flow. This genetic diversity in both chickpea types allows the breeding gains for improving the grain yield and grain Zn biofortification potential of chickpea genotypes. © 2020 Society of Chemical Industry.

Pectic galactan affects cell wall architecture during secondary cell wall deposition.

MAIN CONCLUSION: ß-(1,4)-galactan determines the interactions between different matrix polysaccharides and cellulose during the cessation of cell elongation. Despite recent advances regarding the role of pectic ß-(1,4)-galactan neutral side chains in primary cell wall remodelling during growth and cell elongation, little is known about the specific function of this polymer in other developmental processes. We have used transgenic Arabidopsis plants overproducing chickpea ßI-Gal ß-galactosidase under the 35S CaMV promoter (35S::ßI-Gal) with reduced galactan levels in the basal non-elongating floral stem internodes to gain insight into the role of ß-(1,4)-galactan in cell wall architecture during the cessation of elongation and the beginning of secondary growth. The loss of galactan mediated by ßI-Gal in 35S::ßI-Gal plants is accompanied by a reduction in the levels of KOH-extracted xyloglucan and an increase in the levels of xyloglucan released by a cellulose-specific endoglucanase. These variations in cellulose-xyloglucan interactions cause an altered xylan and mannan deposition in the cell wall that in turn results in a deficient lignin deposition. Considering these results, we can state that ß-(1,4)-galactan plays a key structural role in the correct organization of the different domains of the cell wall during the cessation of growth and the early events of secondary cell wall development. These findings reinforce the notion that there is a mutual dependence between the different polysaccharides and lignin polymers to form an organized and functional cell wall.

Association mapping of loci linked to copper, phosphorus, and potassium concentrations in the seeds of C. arietinum and C. reticulatum.

Due to its high nutritional value, chickpea is one of the most important and cost-effective legumes for human diet. Nutrient elements, such as Cu, P, K have numerous essential functions for the human metabolism. In this study, association mapping of loci linked to the seed Cu, P and K concentrations were performed on a population consisting of 107 Cicer reticulatum and 73 Cicer arietinum individuals in four environments (two locations x two years). A total of 121,840 SNPs were genotyped across 180 individuals by GBS analysis. The association mapping between the SNP markers and the seed Cu, P, K concentrations were identified and eight SNPs were found to be significantly associated with variations in three nutrient elements in more than two environments This research suggests that association mapping is a useful methodology for the identification of loci controlling the Cu, P and K uptake in chickpea seeds for further association mapping, molecular breeding, and marker-assisted selection and plant breeding studies and provides a broader understanding of the relationship between the investigated Cicer species and the effects of environmental conditions.

Overexpression of Cicer arietinum ßIII-Gal but not ßIV-Gal in arabidopsis causes a reduction of cell wall ß-(1,4)-galactan compensated by an increase in homogalacturonan.

In Cicer arietinum, as in several plant species, the ß-galactosidases are encoded by multigene families, although the role of the different proteins is not completely elucidated. Here, we focus in 2 members of this family, ßIII-Gal and ßIV-Gal, with high degree of amino acid sequence identity (81%), but involved in different developmental processes according to previous studies. Our objective is to deepen in the function of these proteins by establishing their substrate specificity and the possible alterations caused in the cell wall polysaccharides when they are overproduced in Arabidopsis thaliana by constructing the 35S::ßIII-Gal and 35S::ßIV-Gal transgenic plants. ßIII-Gal does cause visible alterations of the morphology of the transgenic plant, all related to a decrease in growth at different stages of development. FTIR spectroscopy and immunological studies showed that ßIII-Gal causes changes in the structure of the arabidopsis cell wall polysaccharides, mainly a reduction of the galactan side chains which is compensated by a marked increase in homogalacturonan, which allows us to attribute to galactan a role in the control of the architecture of the cell wall, and therefore in the processes of growth. The 35S::ßIV-Gal plants do not present any phenotypic changes, neither in their morphology nor in their cell walls. In spite of the high sequence homology, our results show different specificity of substrate for these proteins, maybe due to other dissimilar characteristics, such as isoelectric points or the number of N-glycosylation sites, which could determine their enzymatic properties and their distinct action in the cell walls.

The carboxylate-releasing phosphorus-mobilizing strategy can be proxied by foliar manganese concentration in a large set of chickpea germplasm under low phosphorus supply.

Root foraging and root physiology such as exudation of carboxylates into the rhizosphere are important strategies for plant phosphorus (P) acquisition. We used 100 chickpea (Cicer arietinum) genotypes with diverse genetic backgrounds to study the relative roles of root morphology and physiology in P acquisition. Plants were grown in pots in a low-P sterilized river sand supplied with 10 µg P g-1 soil as FePO4 , a poorly soluble form of P. There was a large genotypic variation in root morphology (total root length, root surface area, mean root diameter, specific root length and root hair length), and root physiology (rhizosheath pH, carboxylates and acid phosphatase activity). Shoot P content was correlated with total root length, root surface area and total carboxylates per plant, particularly malonate. A positive correlation was found between mature leaf manganese (Mn) concentration and carboxylate amount in rhizosheath relative to root DW. This is the first study to demonstrate that the mature leaf Mn concentration can be used as an easily measurable proxy for the assessment of belowground carboxylate-releasing processes in a range of chickpea genotypes grown under low-P, and therefore offers an important breeding trait, with potential application in other crops.

Genetic and environmental factors contribute to variation in cell wall composition in mature desi chickpea (Cicer arietinum L.) cotyledons.

Chickpea (Cicer arietinum L.) is an important nutritionally rich legume crop that is consumed worldwide. Prior to cooking, desi chickpea seeds are most often dehulled and cleaved to release the split cotyledons, referred to as dhal. Compositional variation between desi genotypes has a significant impact on nutritional quality and downstream processing, and this has been investigated mainly in terms of starch and protein content. Studies in pulses such as bean and lupin have also implicated cell wall polysaccharides in cooking time variation, but the underlying relationship between desi chickpea cotyledon composition and cooking performance remains unclear. Here, we utilized a variety of chemical and immunohistological assays to examine details of polysaccharide composition, structure, abundance, and location within the desi chickpea cotyledon. Pectic polysaccharides were the most abundant cell wall components, and differences in monosaccharide and glycosidic linkage content suggest both environmental and genetic factors contribute to cotyledon composition. Genotype-specific differences were identified in arabinan structure, pectin methylesterification, and calcium-mediated pectin dimerization. These differences were replicated in distinct field sites and suggest a potentially important role for cell wall polysaccharides and their underlying regulatory machinery in the control of cooking time in chickpea.

Leaf transpiration plays a role in phosphorus acquisition among a large set of chickpea genotypes.

Low availability of inorganic phosphorus (P) is considered a major constraint for crop productivity worldwide. A unique set of 266 chickpea (Cicer arietinum L.) genotypes, originating from 29 countries and with diverse genetic background, were used to study P-use efficiency. Plants were grown in pots containing sterilized river sand supplied with P at a rate of 10 µg P g-1 soil as FePO4 , a poorly soluble form of P. The results showed large genotypic variation in plant growth, shoot P content, physiological P-use efficiency, and P-utilization efficiency in response to low P supply. Further investigation of a subset of 100 chickpea genotypes with contrasting growth performance showed significant differences in photosynthetic rate and photosynthetic P-use efficiency. A positive correlation was found between leaf P concentration and transpiration rate of the young fully expanded leaves. For the first time, our study has suggested a role of leaf transpiration in P acquisition, consistent with transpiration-driven mass flow in chickpea grown in low-P sandy soils. The identification of 6 genotypes with high plant growth, P-acquisition, and P-utilization efficiency suggests that the chickpea reference set can be used in breeding programmes to improve both P-acquisition and P-utilization efficiency under low-P conditions.

Draft genome assembly and annotation of Glycyrrhiza uralensis, a medicinal legume.

Chinese liquorice/licorice (Glycyrrhiza uralensis) is a leguminous plant species whose roots and rhizomes have been widely used as a herbal medicine and natural sweetener. Whole-genome sequencing is essential for gene discovery studies and molecular breeding in liquorice. Here, we report a draft assembly of the approximately 379-Mb whole-genome sequence of strain 308-19 of G. uralensis; this assembly contains 34 445 predicted protein-coding genes. Comparative analyses suggested well-conserved genomic components and collinearity of gene loci (synteny) between the genome of liquorice and those of other legumes such as Medicago and chickpea. We observed that three genes involved in isoflavonoid biosynthesis, namely, 2-hydroxyisoflavanone synthase (CYP93C), 2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase/isoflavone 4'-O-methyltransferase (HI4OMT) and isoflavone-7-O-methyltransferase (7-IOMT) formed a cluster on the scaffold of the liquorice genome and showed conserved microsynteny with Medicago and chickpea. Based on the liquorice genome annotation, we predicted genes in the P450 and UDP-dependent glycosyltransferase (UGT) superfamilies, some of which are involved in triterpenoid saponin biosynthesis, and characterised their gene expression with the reference genome sequence. The genome sequencing and its annotations provide an essential resource for liquorice improvement through molecular breeding and the discovery of useful genes for engineering bioactive components through synthetic biology approaches.

Chickpea Ferritin CaFer1 Participates in Oxidative Stress Response, and Promotes Growth and Development.

Ferritins store and sequester iron, and regulate iron homeostasis. The cDNA for a stress-responsive phytoferritin, previously identified in the extracellular matrix (ECM) of chickpea (Cicer arietinum), was cloned and designated CaFer1. The CaFer1 transcript was strongly induced in chickpea exposed to dehydration, hypersalinity and ABA treatment. Additionally, it has role in the defense against Fusarium oxysporum infection. Functional complementation of the yeast frataxin-deficient mutant, Δyfh1, indicates that CaFer1 functions in oxidative stress. The presence of CaFer1 in the extracellular space besides chloroplast establishes its inimitable nature from that of other phytoferritins. Furthermore, CaFer1 expression in response to iron suggests its differential mechanism of accumulation at two different iron conditions. CaFer1-overexpressing transgenic plants conferred improved growth and development, accompanied by altered expression of iron-responsive genes. Together, these results suggest that the phytoferritin, CaFer1, might play a key role in maintenance of iron buffering and adaptation to environmental challenges.

Genetics and characterization of an open flower mutant in chickpea.

The chickpea (Cicer arietinum L.) is a self-pollinated grain legume with cleistogamous flowers. A spontaneous open-flower mutant, designated OFM-3, was identified in which reproductive organs were not enclosed by the keel petals and thus remained exposed. All 10 stamens in this mutant were free, whereas these are in diadelphous (9 fused + 1 free) condition in normal chickpea flowers. A large number of pods (73%) remained unfilled (empty) in OFM-3, though its pollen fertility was as high as the standard cultivars. The open-flower trait was found to be recessive and controlled by a single gene. OFM-3 was crossed with earlier reported open-flower mutants, ICC 16341 and ICC 16129, to establish trait relationships of genes controlling open flower traits in these mutants. It was found that each of these mutants has a unique gene for open flower trait. The genes controlling open flower trait in ICC 16341, ICC 16129, and OFM-3 were designated ofl-1, ofl-2, and ofl-3, respectively. Breeding lines with open flower trait and higher percentage of filled pods have been developed from the progenies of the crosses of OFM-3 with normal-flowered lines. The open flower trait offers opportunity for exploring hybrid technology in the chickpea.

Chickpea hybridization using in vitro techniques.

Tissue culture techniques play an important role in the utilization of wild Cicer species for the improvement- of cultivated chickpea. Utilization of wild Cicer species has become essential as a series of evolutionary bottlenecks have narrowed the genetic base of chickpea, thus making it susceptible to a range of diseases and pests. Crosses with wild Cicer can broaden its genetic base and introduce useful traits. Except for two wild species, none of the other Cicer species are cross-compatible. To use a range of Cicer species for the improvement of chickpea, embryo rescue and tissue culture techniques are necessary. The success of the cross with incompatible species depended on a range of techniques including the application of growth regulators to pollinated pistils and saving aborting embryos in vitro. Further, the chances of successful transfer of hybrid shoots to soil are greater if the hybrid shoots are grafted to chickpea stocks.

Metallothionein-like gene from Cicer microphyllum is regulated by multiple abiotic stresses.

Cicer microphyllum, a wild relative of cultivated chickpea, is a high altitude cold desert-adapted species distributed in western and trans-Himalayas. A complementary DNA (cDNA) encoding metallothionein-like protein has been identified from a cold-induced subtraction cDNA library from C. microphyllum. The sequence of the cloned metallothionein gene from C. microphyllum (GQ900702) contains 240-bp-long open reading frame and encodes predicted 79-amino acid protein of 7.9 kDa. Sequence analysis identified the motifs characteristic of type II metallothionein and designated as CmMet-2. Southern hybridization confirms a single copy of the CmMet-2 gene in C. microphyllum genome. In situ hybridization indicated spatial transcript regulation of CmMet-2 in root and aerial parts and also confirmed through real-time PCR-based quantitative transcript analysis. The data revealed a significantly low level of transcript in the aerial parts than the roots. Quantitative analysis using real-time PCR assay revealed induction of transcript in all parts of plants in response to cold stress at 4°C. The transcript abundance was found to increase exponentially with time course from 6 to 24 h after exposure. Further, regulation of transcript accumulation in response to abscisic acid application, polyethylene glycol (100 µM)-induced osmotic stress, or ZnSO(4) (1 µM) foliar spray indicated by Northern hybridization suggests the involvement of CmMet-2 in multiple stress response.

Cloning and characterization of a novel NAC family gene CarNAC1 from chickpea (Cicer arietinum L.).

The plant-specific NAC (for NAM, ATAF1,2 and CUC2) proteins have been found to play important roles in plant development and stress responses. In this study, a NAC gene CarNAC1 (for Cicer arietinum L. NAC gene 1) was isolated from a cDNA library constructed with chickpea seedling leaves treated by polyethylene glycol. CarNAC1 encoded a putative protein with 239 amino acids and contained 3 exons and 2 introns within genomic DNA sequence. CarNAC1 had a conserved NAC domain in the N-terminus and the CarNAC1:GFP (green fluorescent protein) fusion protein was localized in the nucleus of onion epidermal cells. Additionally, CarNAC1 exhibited the trans-activation activity which was mapped to the C-terminus. The CarNAC1 transcript was detected in many chickpea organs including seedling leaves, stems, roots, flowers, and young pods, but less accumulated in young seeds. CarNAC1 was induced by leaf age and showed changes in expression during seed development and germination. Furthermore, the expression of CarNAC1 was strongly induced by drought, salt, cold, wounding, H(2)O(2), ethephon, salicylic acid, indole-3-acetic acid, and gibberellin. Our results suggest that CarNAC1 encodes a novel NAC-domain protein and may be a transcriptional activator involved in plant development and various stress responses.