Mitochondrial alternative oxidase pathway helps in nitrooxidative stress tolerance in germinating chickpea.

Mitochondrial alternative oxidase (AOX) is an important protein that can help in regulating reactive oxygen species and nitric oxide in plants. The role of AOX in regulation of nitro-oxidative stress in chickpea is not known. Using germinating chickpea as a model system, we investigated the role of AOX in nitro-oxidative stress tolerance. NaCl treatment was used as an inducer of nitro-oxidative stress. Treatment of germinating seeds with 150 mM NaCl led to reduced germination and radicle growth. The AOX inhibitor SHAM caused further inhibition of germination, and the AOX inducer pyruvate improved growth of the radicle under NaCl stress. Isolated mitochondria from germinated seeds under salt stress not only increased AOX capacity but also enhanced AOX protein expression. Measurement of superoxide levels revealed that AOX inhibition by SHAM can enhance superoxide levels, whereas the AOX inducer pyruvate reduced superoxide levels. Measurement of NO by gas phase chemiluminescence revealed enhanced NO generation in response to NaCl treatment. Upon NaCl treatment there was enhanced tyrosine nitration, which is an indicator of nitrosative stress response. Taken together, our results revealed that AOX induced under salinity stress in germinating chickpea can help in mitigating nitro-oxidative stress, thereby improving germination.

Physio-biochemical responses and crop performance analysis in chickpea upon botanical priming.

Chickpea is a highly nutritious protein-rich source and one of the major crops to alleviate global malnutrition, but poor seed quality affects its productivity. Seed quality is essential for better crop establishment and higher yields, particularly in the uncertain climate change. The present study investigated the impact of botanical priming versus hydropriming and bavistin seed treatment on chickpea seeds. A detailed physiological (germination percentage, root and shoot length, vigour index) and biochemical (amylase, protease, dehydrogenase, phytase, and lipid peroxidation) analysis was carried out in order to assess the effect of priming treatments. Turmeric-primed seeds showed better germination rate (94.5%), seedling length, enzyme activity, and lower malondialdehyde (MDA) content. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed the expression of minor polypeptides of albumin and globulin in the primed seeds. Moreover, field experiments indicated increased crop growth, vigour, days to 50% flowering, yield and its attributing traits in turmeric-primed seeds. Botanical priming can increase chickpea yield by up to 16% over the control group. This low-cost and eco-friendly technique enhances seed and crop performance, making it a powerful tool for augmenting chickpea growth. Therefore, chickpea growers must adopt botanical priming techniques to enhance the quality of seed and crop performance. Moreover, this approach is environmentally sustainable and can help conserve natural resources in the long term. Therefore, this new approach must be widely adopted across the agricultural industry to ensure sustainable and profitable farming practices.

Performance of chickpea (Cicer arietinum L.) in maize-chickpea sequence under various integrated nutrient modules in a Vertisol of Central India.

Present investigation was conducted at the Research Farm of Indian Institute of Soil Science, Bhopal during 2017-18 and 2018-19 to study the performance of chickpea crop under various nutrient management modules in a Vertisol. The field experiment was set up in a randomized block design with three replications of twelve different INM modules. During the rabi seasons of 2017-18 and 2018-19, the chickpea (cv. JG-315) was grown with a set of treatments. The crop's performance was evaluated in terms of growth, yield (grain and straw), nutritional content, and nutrient uptake under different treatments. At crop harvest, the physic-chemical characteristics of the soil were also evaluated. Finally, the relationship between the numerous examined parameters was determined. The results showed that integrated nutrient management modules had a positive impact on chickpea crop performance and productivity when compared to using only inorganic fertilizer. The INM modules dramatically increased soil organic carbon and improved soil health in terms of physical and chemical qualities, in addition to higher crop performance. Among the various modules, (1) application of 75% STCR dose + FYM @ 5t ha-1to maize followed by 100% P only to chickpea and (2) application of FYM @ 20t ha-1to maize followed by FYM @ 5t ha-1 to chickpea increased the productivity and nutrient uptake in chickpea, improved soil physico-chemical properties and reflected as viable technique in improving soil nutrient availability on sustainable basis.

Antioxidant status and their enhancements strategies for water stress tolerance in chickpea / Status antioxidante e suas estratégias de aprimoramento para tolerância ao estresse hídrico no grão-de-bico

Water stress executes severe influences on the plant growth and development through modifying physio-chemical properties. Therefore, a field experiment was designed to evaluate the antioxidant status and their enhancements strategies for water stress tolerance in chickpea on loam and clay loam soils under agro-ecological conditions of Arid Zone Research Institute, Bahawalpur (29.3871 °N, 71.653 °E) and Cholistan farm near Derawer (28.19°N, 71.80°E) of Southern Punjab, Pakistan during winter 2014-15. Experimental treatments comprised of two chickpea cultivars i.e. Bhakhar 2011 (drought tolerant) and DUSHT (drought sensitive), two water stress levels i.e. water stress at flowering stage and water stress at flowering + pod formation + grain filling stage including well watered (control) and two exogenous application of osmoprotectants i.e. glycine betaine (GB) 20 ppm and proline 10 uM including distilled water (control). Results indicated that water stress at various growth stages adversely affects the growth, yield and quality attributes of both chickpea cultivars. Exogenous application of GB and proline improved the growth, yield and quality parameters of both chickpea cultivars even under water stress conditions. However, superior results were obtained with exogenously applied GB on Bhakhar 2011 under well-watered conditions. Similarly, foliar spray of GB on chickpea cultivar Bhakhar 2011 under stress at flowering + pod formation + grain filling stage produced maximum superoxide dismutase, peroxidase and catalase contents. These results suggested that application of GB mitigates the adverse effects of water stress and enhanced tolerance in chickpea mainly due to higher antioxidant enzymes activity, demonstrating the protective measures of plant cells in stress condition. Hence, antioxidants status might be a suitable method for illustrating water stress tolerance in chickpea.

O estresse hídrico exerce fortes influências no crescimento e no desenvolvimento das plantas, modificando as propriedades físico-químicas. Portanto, a presente atividade de pesquisa foi projetada para avaliar o status antioxidante e suas estratégias de aprimoramento para tolerância ao estresse hídrico no grão-de-bico em condiçõesa groecológicas, no Instituto de Pesquisa da Zona Árida, Bahawalpur (29.3871 ° N, 71.653 ° E) e fazenda do Cholistan, perto de Derawer (28.19 ° N, 71,80 ° E), no sul de Punjab, Paquistão, durante Rabi 2014-15. Tratamentos experimentais compostos de dois genótipos de grão-de-bico, como Bhakhar 2011 (tolerante à seca) e DUSHT (sensível à seca), dois níveis de estresse hídrico, ou seja, estresse hídrico no estágio de floração, estresse hídrico na fase de floração e estresse hídrico na fase de floração + formação de vagem + estágio de enchimento de grãos, incluindo água bem controlada (controle) e duas aplicações exógenas de osmoprotetores, isto é, glicina betaína 20 ppm e prolina 10 uM, incluindo água destilada (controle). Os resultados indicaram que o estresse hídrico em vários estágios de crescimento afeta negativamente os atributos de crescimento, rendimento e qualidade de ambas as cultivares de grão-de-bico. A aplicação exógena de glicina betaína e prolina melhorou os parâmetros de crescimento, rendimento e qualidade de ambos os genótipos de grão- de-bico, mesmo sob condições de estresse hídrico. No entanto, resultados superiores foram obtidos com glicina betaína aplicada exogenamente em Bhakhar 2011, em condições bem regadas. Além disso, o spray foliar de glicina betaína na cultivar de grão-de-bico Bhakhar 2011, sob estresse na fase de floração + formação de vagem + enchimento de grãos, produziu o máximo de superóxido dismutase, peroxidase e catalase. Esses resultados sugeriram que a aplicação de glicina betaína atenua os efeitos adversos do estresse hídrico e aumenta a [...].

Mesorhizobium ciceri as biological tool for improving physiological, biochemical and antioxidant state of Cicer aritienum (L.) under fungicide stress.

Fungicides among agrochemicals are consistently used in high throughput agricultural practices to protect plants from damaging impact of phytopathogens and hence to optimize crop production. However, the negative impact of fungicides on composition and functions of soil microbiota, plants and via food chain, on human health is a matter of grave concern. Considering such agrochemical threats, the present study was undertaken to know that how fungicide-tolerant symbiotic bacterium, Mesorhizobium ciceri affects the Cicer arietinum crop while growing in kitazin (KITZ) stressed soils under greenhouse conditions. Both in vitro and soil systems, KITZ imparted deleterious impacts on C. arietinum as a function of dose. The three-time more of normal rate of KITZ dose detrimentally but maximally reduced the germination efficiency, vigor index, dry matter production, symbiotic features, leaf pigments and seed attributes of C. arietinum. KITZ-induced morphological alterations in root tips, oxidative damage and cell death in root cells of C. arietinum were visible under scanning electron microscope (SEM). M. ciceri tolerated up to 2400 µg mL-1 of KITZ, synthesized considerable amounts of bioactive molecules including indole-3-acetic-acid (IAA), 1-aminocyclopropane 1-carboxylate (ACC) deaminase, siderophores, exopolysaccharides (EPS), hydrogen cyanide, ammonia, and solubilised inorganic phosphate even in fungicide-stressed media. Following application to soil, M. ciceri improved performance of C. arietinum and enhanced dry biomass production, yield, symbiosis and leaf pigments even in a fungicide-polluted environment. At 96 µg KITZ kg-1 soil, M. ciceri maximally and significantly (p ≤ 0.05) augmented the length of plants by 41%, total dry matter by 18%, carotenoid content by 9%, LHb content by 21%, root N by 9%, shoot P by 11% and pod yield by 15% over control plants. Additionally, the nodule bacterium M. ciceri efficiently colonized the plant rhizosphere/rhizoplane and considerably decreased the levels of stressor molecules (proline and malondialdehyde) and antioxidant defence enzymes viz. ascorbate peroxidise (APX), guaiacol peroxidise (GPX), catalase (CAT) and peroxidises (POD) of C. arietinum plants when inoculated in soil. The symbiotic strain effectively colonized the plant rhizosphere/rhizoplane. Conclusively, the ability to endure higher fungicide concentrations, capacity to secrete plant growth modulators even under fungicide pressure, and inherent features to lower the level of proline and plant defence enzymes makes this M. ciceri as a superb choice for augmenting the safe production of C. arietinum even under fungicide-contaminated soils.

Bioremedial approach of Pseudomonas stutzeri SPM-1 for textile azo dye degradation.

The optimization of the bacterium Pseudomonas stutzeri SPM-1, obtained from textile wastewater dumping sites of Surat, Gujarat was studied for the degradation of the textile azo dye Procion Red-H3B. The strain showed significant activities of azoreductase (95%), laccase (76%) and NADH-DCIP reductase (88%) at 12, 10 and 8 h of growth, respectively, indicating the evidence for reductive cleavage of the dye. The optimization was carried on phenanthrene enrichment medium followed by exposing it to variable environmental factors and nutritional sources. The complete decolourization of dye (50 mg/L) happened within 20 h of incubation at pH 8 and temperature 32 ± 0.2 °C under microaerophilic condition. Decolourization was monitored with the shifting of absorbance peak in UV-Vis spectrophotometry and HPLC analysis. The changes in the functional groups were confirmed by the presence of new peaks in FT-IR data. GC-MS analysis helped in recognizing the degraded dye compounds thus elucidating the proposed pathway for Procion Red-H3B. The potential of bioremediation process was completed by phytotoxicity test using two plants Vigna radiata and Cicer arietinum. Our study concludes that the strain Pseudomonas stutzeri SPM-1, with its rapid decolourization efficiency holds noteworthy prospective in industrial application for textile wastewater treatment.

Gaseous ozone treatment of chickpea grains, part I: Effect on protein, amino acid, fatty acid, mineral content, and microstructure.

The effect of gaseous ozone (500-1000 ppm) treatment on the protein, amino acid, and fatty acid profiles, mineral content, and the microstructure of the chickpea grains were evaluated. Though protein content was not altered significantly, SDS PAGE profiling exhibited minor modifications in the protein bands of the treated chickpea. The essential amino acids (EAA) and total amino acids (TAA) slightly decreased, ratio of EAA to TAA increased, while the calculated protein efficiency ratio decreased. Significant decrease in the SH content and non-significant increase in SS content was observed at higher doses of ozone. The overall saturated and unsaturated fatty acids (%) were in the range of 13.05-13.49 and 86.51-87.61, respectively. The minerals were stable and the HCl extractability decreased in the ozonated samples. There was some minor degradation of intracellular cell wall and distribution of starch and protein bodies in the ozonated sample.

Effect of chromium (VI) toxicity on morpho-physiological characteristics, yield, and yield components of two chickpea (Cicer arietinum L.) varieties.

The ever-increasing industrial activities over the decades have generated high toxic metal such as chromium (Cr) that hampers the crop productivity. This study evaluated the effect of Cr on two chickpea (Cicer arietinum L.) varieties, Pusa 2085 and Pusa Green 112, in hydroponic and pot-grown conditions. First, growth parameters (seed germination, seedling growth, and biomass production) and physio-biochemical parameters (oxidative stress and the content of antioxidants and proline) were measured to evaluate the performance of both varieties grown hydroponically for 21 days at concentrations of 0, 30, 60, 90 and 120 µM Cr in the form of potassium dichromate (K2Cr2O7). In both varieties, significantly deleterious effects on germination and seedling growth parameters were observed at 90 and 120 µM, while growth was stimulated at 30 µM Cr. Significant increases in malondialdehyde and hydrogen peroxide content and electrolyte leakage demonstrated enhanced oxidative injury to seedlings caused by higher concentrations of Cr. Further, increasing concentrations of Cr positively correlated with increased proline content, superoxide dismutase activity, and peroxide content in leaves. There was also an increase in peroxisomal ascorbate peroxidase and catalase in the leaves of both varieties at lower Cr concentrations, whereas a steep decline was recorded at higher Cr concentrations. In the pot experiments conducted over two consecutive years, growth, yield, yield attributes, grain protein, and Cr uptake and accumulation were measured at different Cr concentrations. Pusa Green 112 showed a significant reduction in plant growth, chlorophyll content, grain protein, pod number, and grain yield per plant when compared with Pusa 2085. Overall, our results indicate that Pusa 2085 has a higher Cr tolerance than Pusa Green 112. Therefore, Pusa 2085 could be used to further elucidate the mechanisms of Cr tolerance in plants and in breeding programmes to produce Cr-resistant varieties.

Molecular and Physiological Alterations in Chickpea under Elevated CO2 Concentrations.

The present study reports profiling of the elevated carbon dioxide (CO2) concentration responsive global transcriptome in chickpea, along with a combinatorial approach for exploring interlinks between physiological and transcriptional changes, important for the climate change scenario. Various physiological parameters were recorded in two chickpea cultivars (JG 11 and KAK 2) grown in open top chambers under ambient [380 parts per million (ppm)] and two stressed/elevated CO2 concentrations (550 and 700 ppm), at different stages of plant growth. The elevated CO2 concentrations altered shoot and root length, nodulation (number of nodules), total chlorophyll content and nitrogen balance index, significantly. RNA-Seq from 12 tissues representing vegetative and reproductive growth stages of both cultivars under ambient and elevated CO2 concentrations identified 18,644 differentially expressed genes including 9,687 transcription factors (TF). The differential regulations in genes, gene networks and quantitative real-time polymerase chain reaction (qRT-PCR) -derived expression dynamics of stress-responsive TFs were observed in both cultivars studied. A total of 138 pathways, mainly involved in sugar/starch metabolism, chlorophyll and secondary metabolites biosynthesis, deciphered the crosstalk operating behind the responses of chickpea to elevated CO2 concentration.

Impacts of plant growth promoters and plant growth regulators on rainfed agriculture.

Demand for agricultural crop continues to escalate in response to increasing population and damage of prime cropland for cultivation. Research interest is diverted to utilize soils with marginal plant production. Moisture stress has negative impact on crop growth and productivity. The plant growth promoting rhizobacteria (PGPR) and plant growth regulators (PGR) are vital for plant developmental process under moisture stress. The current study was carried out to investigate the effect of PGPR and PGRs (Salicylic acid and Putrescine) on the physiological activities of chickpea grown in sandy soil. The bacterial isolates were characterized based on biochemical characters including Gram-staining, P-solubilisation, antibacterial and antifungal activities and catalases and oxidases activities and were also screened for the production of indole-3-acetic acid (IAA), hydrogen cyanide (HCN) and ammonia (NH3). The bacterial strains were identified as Bacillus subtilis, Bacillus thuringiensis and Bacillus megaterium based on the results of 16S-rRNA gene sequencing. Chickpea seeds of two varieties (Punjab Noor-2009 and 93127) differing in sensitivity to drought were soaked for 3 h before sowing in fresh grown cultures of isolates. Both the PGRs were applied (150 mg/L), as foliar spray on 20 days old seedlings of chickpea. Moisture stress significantly reduced the physiological parameters but the inoculation of PGPR and PGR treatment effectively ameliorated the adverse effects of moisture stress. The result showed that chickpea plants treated with PGPR and PGR significantly enhanced the chlorophyll, protein and sugar contents. Shoot and root fresh (81%) and dry weights (77%) were also enhanced significantly in the treated plants. Leaf proline content, lipid peroxidation and antioxidant enzymes (CAT, APOX, POD and SOD) were increased in reaction to drought stress but decreased due to PGPR. The plant height (61%), grain weight (41%), number of nodules (78%) and pod (88%), plant yield (76%), pod weight (53%) and total biomass (54%) were higher in PGPR and PGR treated chickpea plants grown in sandy soil. It is concluded from the present study that the integrative use of PGPR and PGRs is a promising method and eco-friendly strategy for increasing drought tolerance in crop plants.

Role of Ascorbic acid, Glutathione and Proline Applied as Singly or in Sequence Combination in Improving Chickpea Plant through Physiological Change and Antioxidant Defense under Different Levels of Irrigation Intervals.

In recent years, the harmful effects of drought stress have been be mitigated by using bioactive compounds such as antioxidants and osmolytes. In this research, pot experiments were carried out to investigate the effects of ascorbic acid, glutathione and proline on alleviating the harmful effect of drought stress in chickpea plants during season 2017. Chickpea plant seeds were soaked in ascorbic acid (0.75 mM), glutathione (0.75 mM), proline (0.75 mM) singly and/or in sequence combinations for 4 h and then planted in pots. The pots were irrigated with water after seven days (to serve as control), after 14 days (moderate drought stress) and after 28 days (severe drought stress). The sequence combination of antioxidants and proline under drought stress has not been studied yet. The results showed significantly decreased in plant growth, yielding characteristics, photosynthetic pigments and soluble protein content in response to moderate and severe drought stress. Moreover, treatment with antioxidants caused increment the antioxidant enzyme activity, non-enzymatic antioxidant (ascorbic acid and glutathione) contents and endogenous proline in stressed and unstressed plants. In conclusion, The sequence combination of antioxidants and proline caused improvement in plant growth under drought stress by up-regulating the antioxidant defense system and osmolyte synthesis.

Amelioration effect of chromium-tolerant bacteria on growth, physiological properties and chromium mobilization in chickpea (Cicer arietinum) under chromium stress.

In this study, chromium (Cr)-tolerant bacteria were test for their efficiency in alleviating Cr stress in Cicer arietinum plants. On the basis of 16S rRNA gene analysis, the isolates were identified belonging to genus Stenotrophomonas maltophilia, Bacillus thuringiensis B. cereus, and B. subtilis. The strains produced a considerable amount of indole-3-acetic acid in a medium supplemented with tryptophan. The strains also showed siderophore production (S2VWR5 and S3VKR17), phosphorus production (S1VKR11, S3VKR2, S3VKR16, and S2VWR5), and potassium solubilization (S3VKR2, S2VWR5, and S3VKR17). Furthermore, the strains were evaluated in pot experiments to assess the growth promotion of C. arietinum in the presence of chromium salts. Bacterization improved higher root and shoot length considerably to 6.25%-60.41% and 11.3%-59.6% over the control. The plants also showed increase in their fresh weight and dry weight in response to inoculation with Cr-tolerant strains. The accumulation of Cr was higher in roots compared to shoots in both control and inoculated plants, indicating phytostabilization of Cr by C. arietinum. However, phytostabilization was found to be improved manifold in inoculated plants. Apart from the plant attributes, the amendment of soil with Cr and Cr-tolerant bacteria significantly increased the content of total chlorophyll and carotenoids, suggesting the inoculant's role in protecting plants from deleterious effects. This work suggests that the combined activity of Cr-tolerant and plant growth-promoting (PGP) properties of the tested strains could be exploited for bioremediation of Cr and to enhance the C. arietinum cultivation in Cr-contaminated soils.

Simultaneous scavenging of Cr(VI) from soil and facilitation of nutrient uptake in plant using a mixture of carbon microfibers and nanofibers.

Plant growth and yield are adversely affected by the uptake of toxic hexavalent chromium (Cr(VI)) from soil. The present study describes a facile technique to minimize the uptake of Cr(VI) by chickpea (Cicer arietinum) plant from soil using microporous activated carbon microfiber (ACF). Simultaneously, nano-sized carbon nanofibers (CNFs), grown over the ACF substrate, are used as an efficient carrier of the Cu micronutrient from soil to root, shoot and leaf of the plants. Adsorption, seed germination and plant growth experiments are performed in Cr-stressed medium. The ACF, used as the adsorbent for Cr(VI) in metal-stressed soil (100 mg Cr kg-1 of soil) shows the metal loading of ∼23 mg g-1. Cr(VI) up to 50 mg L-1 concentration causes no stress during germination of chickpea seeds in Murashige and Skoog (MS) medium. A dose of 500 mg-mixture (treatment) per kg-soil increases root and shoot lengths by 52 and 11%, respectively than the control, during plant growth in the metal-stressed soil, attributed to an effective translocation of Cu-CNF through plant cells. Whereas Cr uptake by plant decrease to ∼46%, Cu uptake increase up to ∼120% in comparison to control by the mixture treatment. Protein and chlorophyll contents also significantly increased (*p < 0.05) with the application of treatment. The data clearly show that the mixture of ACF and Cu-CNF can be successfully used for the simultaneous scavenging of Cr(VI) from soil by adsorption over ACF and increased uptake of Cu by plants using the CNFs as the micronutrient carrier.

Hexavalent chromium stress response, reduction capability and bioremediation potential of Trichoderma sp. isolated from electroplating wastewater.

In the present study we are investigating the Cr(VI) reduction potential of a multi-metal tolerant fungus (isolate CR700); isolated from electroplating wastewater. Based on the ITS region sequencing, the isolate was identified as Trichoderma lixii isolate CR700 and able to tolerate As(2000 mg/L), Ni(1500 mg/L), Zn(1200 mg/L), Cu(1200 mg/L), Cr(1000 mg/L), and 100 mg/L of Pb and Cd evident from tolerance assay. Cr(VI) reduction experiment was conducted in Erlenmeyer flasks containing different concentration of Cr(VI) (0-200 mg/L) amended potato dextrose broth medium followed by inoculating with a disk (0.5 cm diameter) of 7 days grown isolate CR700, and achieved a maximum of 99.4% within 120 h at 50 mg/L of Cr(VI). However, the accumulation of total Cr by isolate CR700 was 2.12 ±â€¯0.15 mg/g of dried biomass at the same concentration after 144 h of exposure. Isolate CR700 showed the capability to reduce Cr(VI) at different physicochemical stress conditions such as pH, temperature, heavy metals, metabolic inhibitor and also in tannery wastewater. Fungus exhibited multifarious morphological and biochemical response under the exposure of Cr(VI); the scanning electron microscopic analysis revealed that Cr(VI) treated mycelia of isolate CR700 comparatively irregular, aggregated and swelled than without treated mycelia which might be due to the tolerance mechanism and vacuolar compartmentation of chromium. Moreover, energy dispersive spectroscopy and x-ray photoelectron spectroscopic analysis exposed the Cr(III) precipitation on the mycelia surface of isolate CR700 and Fourier-transform infrared spectroscopic analysis suggested the contribution of the protein associated functional group in the complexation of Cr(VI). The phytotoxicity test of fungal treated 100 mg/L of Cr(VI) supernatant on Vigna radiata and Cicer arietinum revealed the successful detoxification/remediation of Cr(VI).

Analysis of chickpea gene co-expression networks and pathways during heavy metal stress.

Crop productivity and yield are adversely affected by abiotic and biotic stresses. Therefore, finding out the genes responsible for stress tolerance is a significant stride towards crop improvement. A gene co-expression network is a powerful tool to detect the most connected genes during heavy metal (HM) stress in plants. The most connected genes may be responsible for HM tolerance by altering the different metabolic pathways during the biotic and abiotic stress. In the same line we have performed the GSE86807 microarray analysis of chickpea during exposure to chromium, cadmium and arsenic and analyzed the data. Common differentially expressed genes (DEGs) during exposure to chromium, cadmium and arsenic were identified and a co-expression network study was carried out. Hub and bottleneck genes were explored on the basis of degree and betweenness centrality, respectively. A gene set enrichment analysis study revealed that genes like haloacid dehydrogenase, cinnamoyl CoA reductase, F-box protein, GDSL esterase lipase, cellulose synthase, beta-glucosidase 13 and isoflavone hydroxylase are significantly enriched and regulate the different pathways like riboflavin metabolism, phenyl propanoid biosynthesis, amino acid biosynthesis, isoflavonoid biosynthesis and indole alkaloid biosynthesis.

Pseudomonas citronellolis; a multi-metal resistant and potential plant growth promoter against arsenic (V) stress in chickpea.

Soil micro-biota plays a vital role in maintaining plant growth and fitness under normal and adverse conditions. Pseudomonas is one of the most important free-living and copious genera in south-west Punjab and involved in plant growth promotion under heavy metal stress. In this study, we have studied microbial diversity of the agricultural and marginal land based on 16S rRNA gene and screened eight strains of Pseudomonas for its tolerances towards various heavy metals and for plant growth promoting properties (PGP). The best strain is tested in chickpea plants against Arsenic (As5+) stress. All the strains responded differently to heavy metals viz. Arsenic, (As5+ (0.3-0.5M) and As3+ (250 µg mL-1) Cadmium (Cd2+) (250-350 µg mL-1), Chromium (Cr2+) (200-350 µg mL-1) and Mercury (Hg2+) (1-2 µg mL-1). Out of eight strains, only two strains (KM594398 and KM594397) showed plant growth promoting characters, concurrently they were highly tolerant to Arsenic (As5+). Pseudomonas citronellolis (PC) (KM594397) showed the best results in terms of As5+ tolerance and plant growth promoting activity, hence further tested for actual plant growth response in chickpea (Cicer arietinum L.) under As5+ (10-160 mg kg-1) stress. Pseudomonas citronellolis enhanced plant growth and dry biomass under As5+ stress. High As5+ tolerance and plant growth promoting activity of Pseudomonas citronellolis in chickpea especially designate this strain suitable for marginal lands and heavy metals contaminated sites.

SA and AM symbiosis modulate antioxidant defense mechanisms and asada pathway in chickpea genotypes under salt stress.

Salt stress disturbs redox homeostasis by perturbing equilibrium between generation and removal of reactive oxygen species (ROS), which alters the normal metabolism of plants through membrane damage, lipid peroxidation and denaturation of proteins. Salicylic acid (SA) seed priming and arbuscular mycorrhizal (AM) fungi impart salt tolerance in legumes by maintaining redox balance. The present investigation focused on the relative and combined applications of SA and Rhizoglomus intraradices in scavenging ROS in Cicer arietinum L. (chickpea) genotypes (salt tolerant-PBG 5, relatively sensitive-BG 256) subjected to salt stress. Despite the enhanced antioxidant mechanisms under salt stress, ROS (superoxide, O2- and hydrogen peroxide, H2O2) accumulation increased significantly and induced lipid peroxidation and lipoxygenase (LOX) activities, which disrupted membrane stability, more in BG 256 than PBG 5. Salt stress also caused redox imbalance by lowering ascorbate/dehydroascorbate (ASA/DHA) and reduced glutathione/oxidized glutathione (GSH/GSSG) ratios, indicating that redox-homeostasis was crucial for salt-tolerance. Exogenous SA was more promising in reducing ROS-generation and lipid-peroxidation, which provided higher membrane stability as compared to AM inoculation. Although, the enzymatic antioxidants were more active in SA treated plants, yet, AM inoculation outperformed in increasing reformative enzyme activities of Foyer-Halliwell-Asada cycle, which resulted in higher plant biomass in a genotype-dependent manner. SA increased AM root colonization and provided functional complementarity to R. intraradices and thereby strengthening antioxidant defense mechanisms through their cumulative contribution. The study suggested the use of +SA+AM as an eco-friendly tool in imparting salt tolerance in chickpea genotypes subjected to long-term salinity.

Chitosan nanoparticles loaded with thiamine stimulate growth and enhances protection against wilt disease in Chickpea.

Nanoencapsulation is considered as one of the unique technique for increasing the bioavailability, solubility and retention time of bioactive compounds. In this study, thiamine was incorporated into the chitosan nanoparticles and characterized through FTIR, DLS, SEM, TEM and XRD analyses. Zeta potential of the synthesized nanoparticles was found to be 37.7 mV. The encapsulation efficiency of chitosan nanoparticle was 90 ± 3%. Application of thiamine loaded chitosan nanoparticle enhanced seed germination and growth of chickpea seedlings when compared to untreated control seeds. Treated seedlings showed enhanced production of indole acetic acid (IAA). Foliar application of synthesized nanoparticle induced defense enzymes in leaves and roots of chickpea plants. Decreased cell death in the chickpea roots of treated plants was observed when compared to control under green house condition. These results showed that the thiamine loaded chitosan nanoparticle can be used as a growth stimulator as well as a defense activator in chickpea.

Metabolic and physiological changes induced by plant growth regulators and plant growth promoting rhizobacteria and their impact on drought tolerance in Cicer arietinum L.

Plant growth regulators (PGRs) and plant growth promoting rhizobacteria (PGPRs) play an important role in mitigating abiotic stresses. However, little is known about the parallel changes in physiological processes coupled with metabolic changes induced by PGRs and PGPRs that help to cope with drought stress in chickpeas. The present investigation was carried out to study the integrative effects of PGRs and PGPRs on the physiological and metabolic changes, and their association with drought tolerance in two chickpea genotypes. Inoculated seeds of two chickpea genotypes, Punjab Noor-2009 (drought sensitive) and 93127 (drought tolerance), were planted in greenhouse condition at the University of Florida. Prior to sowing, seeds of two chickpea varieties were soaked for 3 h in 24 h old cultures of PGPRs (Bacillus subtilis, Bacillus thuringiensis, and Bacillus megaterium), whereas, some of the seeds were soaked in distilled water for the same period of time and were treated as control. Plant growth regulators, salicylic acid (SA) and putrescine (Put), were applied on 25 days old seedlings just prior to the induction of drought stress. Drought stress was imposed by withholding the supply of water on 25-day-old seedlings (at the three-leaf stage) and continued for the next 25 days until the soil water content reached 14%. Ultrahigh-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) analysis concomitant with physiological parameters were carried out in chickpea leaves at two-time points i.e. 14 and 25 d after imposition of drought stress. The results showed that both genotypes, treated with PGRs and PGPRs (consortium), performed significantly better under drought condition through enhanced leaf relative water content (RWC), greater biomass of shoot and root, higher Fv/FM ratio and higher accumulation of protein, sugar and phenolic compounds. The sensitive genotype was more responsive than tolerant one. The results revealed that the accumulation of succinate, leucine, disaccharide, saccharic acid and glyceric acid was consistently higher in both genotypes at both time points due to PGRs and PGPRs treatment. Significant accumulation of malonate, 5-oxo-L-proline, and trans-cinnamate occurred at both time points only in the tolerant genotype following the consortium treatment. Aminoacyl-tRNA, primary and secondary metabolite biosynthesis, amino acid metabolism or synthesis pathways, and energy cycle were significantly altered due to PGRs and PGPRs treatment. It is inferred that changes in different physiological and metabolic parameters induced by PGRs and PGPRs treatment could confer drought tolerance in chickpeas.

Changes in digestibility of proteins from chickpeas (Cicer arietinum L.) germinated in presence of selenium and antioxidant capacity of hydrolysates.

Germination in the presence of selenium (Se) is an alternative to increase the healthy properties of seeds. This study aimed to compare the Se accumulation in different protein fractions from germinated chickpea (Cicer arietinum L.) and the effect on digestibility and cellular antioxidant activity (CAA) of protein hydrolysates. Chickpeas were germinated during four days after soaking with sodium selenite (0, 1, or 2 mg/100 g seeds). Total protein (TP) and glutelin (Glu), albumin (Alb) and globulin (Glo) fractions were digested and ultrafiltrated through a 10 kDa membrane. Se accumulated in the order of Glu > Alb > Glo. Ultrafiltrated Glu hydrolysate of four days germinated chickpeas treated with 2 mg Na2SeO3/100 g increased CAA (51.47%), demonstrating the potential health benefits of selenization. The intensity of vicilin bands (34-37 kDa) increased from the second to the fourth day compared with the control samples. Glo digestibility was higher in selenized chickpea sprouts.