Satvir Kaur Grewal

Differential proline metabolism in vegetative and reproductive tissues determine drought tolerance in chickpea

Proline is emerging as a critical component of drought tolerance and fine tuning of its metabolism under stress affects the plants sensitivity and response to stress. Thus the study was carried out to analyse the effect of water deficit on the proline content and principal enzymes involved in its synthesis (Δ1-pyrolline-carboxylate synthetase) and catabolism (proline dehydrogenase) at different developmental stages and in different organs (roots, nodules, leaves, pod wall, and seeds) of two chickpea (Cicer arietinum L.) cultivars differing in drought tolerance (drought tolerant ICC4958 and drought sensitive ILC3279). It was observed that increased Δ1-pyrolline-carboxylate synthetase activity under moderate stress in roots and nodules of ICC4958 caused an increase in proline content during initiation of reproductive development whereas increased proline dehydrogenase activity in nodules and leaves at this period helped to maintain reducing power and energy supply in tissues and proper seed development as seed biomass increased consistently up to maturity. On the other hand, roots and nodules of ILC3279 responded to stress by increasing proline content after the developmental phase of reproductive organs was over (near maturity) which negatively affected the response of pod wall to stress. Concurrent increase in activities of Δ1-pyrolline-carboxylate synthetase and proline dehydrogenase in pod wall of ILC3279 aggravated the oxidative stress and affected seed development as seed biomass initially increased rapidly under stress but was unaffected near maturity.

Free radical scavenging activities can mitigate the effect of water stress in chickpea

Abstract. To get a comprehensive view of drought tolerance mechanisms, the influence of water deficit stress on antioxidative capacity due to scavenging of free radicals and ability to maintain reduced cell state was investigated in roots, nodules, leaves, pod wall and seeds of two chickpea cultivars differing in rooting behaviour. ICC4958 (deep rooted) possessed better ability to combat water deficit-induced oxidative stress relative to ILC3279 (shallow rooted) as revealed by increase in total phenol, reducing power, ferric reducing ability and capacity to scavenge 2,2-Diphenyl-1-picryl hydrazyl (DPPH) and OH free radicals. Effect of water deficit stress on photosynthetic pigments of these cultivars was also studied. The investigation revealed that the influence of water stress in enhancing antioxidative capacity was most prominent in roots of ICC4958 among all other tissues as revealed by increased total phenols, DPPH and OH free radical scavenging activity and total reducing power under stress. However, roots of ILC3279 suffered a decrease in total phenolic content, total reducing power and DPPH free radical scavenging activity under prolonged stress, which was reflected in reduced antioxidative defence in reproductive tissues like decreased reducing power in pod wall and ferric-reducing antioxidant power ability in seeds.

Water deficit stress tolerance in chickpea is mediated by the contribution of integrative defence systems in different tissues of the plant

Drought induces heavy yield losses in chickpea (Cicer arietinum L.). Besides understanding the physiological and biochemical parameters contributing to drought tolerance, we need to understand the importance of one tissue in combatting drought stress-induced oxidative stress and influencing the antioxidative defence system in other tissues. The study was conducted to examine the influence of drought stress conditions on the antioxidative defence system and physiology in different tissues such as roots, leaves, nodules, pod walls and seeds at various vegetative and reproductive growth stages in two chickpea cultivars differing in rooting behaviour: ICC4958 (deep rooted) and ILC3279 (shallow rooted). The traits contributing to drought tolerance in ICC4958 were increased root area, decreased leaf area index or increase in root area, decreased leaf area; ILC3279 displayed a decrease in root area and an increase in LAI. The adaptation of ICC4958 was also accompanied by biochemical adjustments, like increases in antioxidative enzymes (superoxide dismutase, peroxidase, ascorbate peroxidase, glutathione reductase and catalase) and nonenzymatic antioxidants (ascorbic acid, proline and stress-induced proteins). However, increases in antioxidant enzymes, nonenzymatic antioxidants and proteins in ILC3279 were lower than in ICC4958. The lower malondialdehyde content and membrane permeability index in ICC4958 might be responsible for reduced damage under drought stress. Increased H2O2 content in ICC4958 was related to enhanced antioxidative defence, emphasising its role as a signalling molecule under stress. This is the first study conducted on drought stress-induced enzymatic and nonenzymatic antioxidative defence systems in underground, aboveground vegetative and reproductive tissues in chickpea cultivars differing in rooting behaviour.

Variation of morpho-physiological traits in geographically diverse pigeonpea [Cajanus cajan (L.) Millsp] germplasm under different phosphorus conditions

ABSTRACT Genotypic variation for morpho-physiological parameters, phosphorus (P) content and root acid phosphatase activity was studied in 52 pigeonpea genotypes. Data related to shoot (length, dry weight, number of leaves, and leaf area), root (volume, length, dry weight, area, perimeter, and number of root tips), acid phosphatase activity, and P content (root, stem, and leaf) were recorded at 60 days after sowing (DAS). The P use efficient genotypes showed high root length, root area, root perimeter, root dry weight, P content in leaves, and root to shoot dry weight ratio under the P not added condition. Significant variation was found among genotypes for root- and shoot-associated characteristics under both P treatments. The P use efficient genotypes with improved root morphological phenes have potential to acquire and utilize more P from immobile soil bound P sources may be of additional factor for increasing efficiency of acquisition and utilization of supplied P fertilizer.

Induced defense dynamics in plant parts is requisite for resistance to Helicoverpa armigera (Hubner) infestation in chickpea

Helicoverpa armigera is the most serious insect pest in chickpea that causes significant yield losses due to its feeding on vegetative (leaves) and reproductive (developing pods and seeds) parts of plants. The present aim of study was to explore response dynamics of induced defence mechanism in leaves, podwall and seeds of ten chickpea genotypes (ICC 506, ICCV 10, ICC 10393, 5283, RSG 963, GL 25016, GL 26054, ICCL 86111, ICC 3137, L 550) after insect infestation. Two chickpea genotypes namely ICC 3137 and L 550 were found to be highly susceptible to Helicoverpa armigera infestation due to higher leaf and pod damage in them as compared to rest of eight genotypes which are found to be considerably resistant due to lower damage. Insect infestation induced decreased activities of defensive enzymes such as peroxidase (POD), catalase (CAT), glutatione reductase (GR) and polyphenol oxidase (PPO), decreased free radical scavenging activities in terms of 2,2-diphenyl-1-picryl hydrazyl (DPPH), decreased contents of signaling molecules such as nitric oxide ((NO), hydrogen peroxide (H2O2), reduced content of insect feeding behaviour regulating molecules such as total phenols, trypsin inhibitor and accumulation of membrane damage marker such as malondialdehyde (MDA) in leaves of ICC 3137 and L 550; decreased POD activity, nitric oxide content and H2O2 in podwall of L550; decreased SOD, GR, nitric oxide content and H2O2 in seeds of L550 resulted in aggravation of infestation induced oxidative stress and makes these genotypes more vulnerable to insect damage. The resistance of rest eight chickpea genotypes to insect infestation was due to the integrative effect of up regulated defensive components in leaves, podwall and seeds such as enhanced activities of CAT, POD, GR, PPO and PAL along with accumulation of H2O2` and total phenols in leaves, increased SOD, POD, GR and PPO activities along with increased contents of trypsin inhibitor and total phenols in podwall; increased SOD, GR, PPO activities and accumulated total phenols in seeds of resistant chickpea genotypes might be responsible for causing significant shift in oxidative status of these genotypes due to scavenging of free radicals, maintenance of membrane integrity and deterrent to insect feeding. Induced glycine betaine after herbivory was found to be positively correlated with superoxide dismutase and trypsin inhibitors. H2O2 content was positively correlated with trypsin inhibitor, DPPH, ferric reducing antioxidant power (FRAP) and total phenols in leaves and with FRAP, DPPH and total phenols in pod wall indicating that H2O2 might be stimulating the cascade that will be helping to scavenge free radical species and correlation with phenols and trypsin inhibitor indicated that it act as toxicant to insect feeding.

Genotypic Variation for Phosphorus Efficiency of Pigeonpea Genotypes under Varied Phosphorus Levels

and H2PO4 ) moreover, some soluble organic phosphorus compounds are also absorbed (Rubya and Md, 2016). Phosphorus never found as a free state in soil, it forms complexes with several cations such as Fe, Ca, Mg and Al. Phosphorus is a nonrenewable because the phosphate rich rocks are formed slowly (Clemens et al., 2016). It has been hypothesized that rock phosphate will exhaust in 2033-34 years and then production of fertilizers reduced and the prices are expected to rise (Cordell et al., 2009). Phosphorus fertilizers due to hike in prices as well as environmental contaminants need to be replaced with safe and economical International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 11 (2017) pp. 3633-3647 Journal homepage: http://www.ijcmas.com

Defense system in chickpea genotypes differing in tolerance to Helicoverpa armigera infestation

Antioxidative enzymes, non enzymic antioxidants and signaling molecules were compared in leaves and podwall of ten chickpea genotypes namely ICC 506, ICCV 10, ICC 10393, 5282, RSG 963, GL 25016, GL 26054, ICCL 86111, ICC 3137 and L 550 after Helicoverpa armigera infestation. Two chickpea genotypes (ICC 3137 and L 550) were found to be susceptible and rest of eight genotypes were found to be resistant on the basis of leaf and pod damage due to to Helicoverpa armigera infestation. The activities of defensive enzymes like, peroxidase (POD), ascorbate peroxidase(APX) and glutathione reductase (GR); content of nitric oxide (NO), 2,2-diphenyl-1-picryl hydrazyl (DPPH), ferric reducing antioxidant power(FRAP), glycine betaine (GB), total phenols (TP) and proline were higher in leaves and pod wall of resistant genotypes than susceptible genotypes. Genotype 5282 was found to be the most resistant having lower leaf and pod damage and it had higher POD, nitric oxide, DPPH, FRAP, total phenols and proline content.

Polymorphism and Iron and Zinc Contents in Fababean Genotypes

Twenty seven fababean genotypes acquired from different agroclimatic regions of India were evaluated for iron and zinc content and genetic diversity using RAPD markers. The number of pods/plant, number of seeds/pod and 100 seed weight, iron and zinc content in the genotypes ranged from 14–46, 2.8–3.6, 20.4–28.3, 2.47–4.19 mg/100g and 2.55–4.90 mg/100g, respectively. The genotypes analyzed for their genetic diversity and relationship using RAPD primers showed polymorphism and polymorphic information content and resolving power varied from 0.61 to 0.88 and 0.88–6.66, respectively. Cluster analysis based on mineral content and genetic diversity showed that the genotypes HB184 and HB186 as well as PRT12 and RFB5 showed close relationship both through molecular and nutritional analysis.

Antioxidants Potential in Seeds of Chickpea Genotypes Differing in Helicoverpa armigera Resistance

Seeds of fourteen chickpea genotypes (GL 25016, GL 26054, ICCL 86111, GL 28185, GL 29303, GL 28389, CE 1, CE 9, CE 35, GL 28390, PBG 5, GPF 2, GL 21107 and L 550) were evaluated for their stress tolerance capacity against Helicoverpa armigera. DPPH radical scavenging activity, glycine betaine, reducing power, total protein, trypsin inhibitor, H2O2 and proline was higher in seeds of resistant chickpea genotypes than the susceptible genotype (L550). MDA content was higher in susceptible genotype than the resistant genotypes. DPPH radical scavenging activity was negatively correlated with pod damage which shows higher free radical scavenging activity in resistant genotypes than susceptible genotype. Clustering of chickpea genotypes shows that resistant genotypes and moderately resistant genotypes form cluster with each other while susceptible genotypes do not form any cluster with any other genotype. SDS-PAGE results showed that content of higher molecular weight protein was higher in resistant genotypes than the susceptible genotype while low molecular weight protein was higher in susceptible genotypes than the resistant genotypes.

Upregulation of Superoxide Dismutase and Catalase along with Proline Accumulation Mediates Heat Tolerance in Lentil (Lens culinaris Medik.) Genotypes during Reproductive Stage

Heat stress during reproductive stage of lentil leads to array of physiological and morphological changes affecting lentil production. The effect of high temperature stress (30°-35°) was studied on thirty three lentil genotypes during winter (rabi) trial 2013–2014. Six genotypes comprising three tolerant (LL1372, LL1361, LL1396) and three sensitive (EC78390, LL1380, LL1390) were selected which further raised under timely sown (TS) and late sown (LS) conditions during winter (rabi) trial 2014–15 for biochemical analysis. The higher accumulation of proline content along with higher activities of superoxide dismutase (SOD) and catalase (CAT) was observed in late sown tolerant genotypes, might be helping in reducing oxidative stress caused by reactivite oxygen species (ROS). The higher accumulation of malondialdehyde (MDA) and hydrogen peroxide (H2O2) content was found in sensitive genotypes might be responsible for membrane damage. The positive and significant correlation was observed in CAT, SOD, and proline whereas these three biochemical parameters showed negative correlation with MDA and hydrogen peroxide content.