Drought-Induced Morpho-Physiological, Biochemical, Metabolite Responses and Protein Profiling of Chickpea (Cicer arietinum L.)

The chickpea (Cicer arieitnum L.) is an important food legume crop of the family Fabaceae with high protein levels that is widely grown in rainfed areas prone to drought stress. It is a self-pollinated cool season crop with a true diploid (2n = 16) nature. It is relatively cheap and a high source of protein. About 90% of the chickpea crop is grown by the use of residual moisture in the soil without depending on irrigation. In the present study, two varieties of chickpea, namely ICC 4958 and HC-6, were grown under three field capacities (FC) (100% FC, 50% FC and 25% FC). Samples were taken three times, i.e., 15, 30 and 45 days after sowing (DAS). Parameters such as morphological, physiological, biochemical, metabolite and protein profiling of the two varieties were completed. Morphological parameters such as shoot length (14.2%), number of branches (20.7%), number of leaves (17.5%) and yield (56%) declined as the drought level increased and other characteristics such as root length (9.7%), number of flowers (24.5%) and number of pods (34.4%) increased as drought stress progressed. Physiological parameters such as relative water content (RWC) (13.5%), cell membrane stability (CMS) (29.6%) and chlorophyll content decreased, whereas electrolyte conductivity (EC) (38%) increased in both the varieties as field capacity decreased. Biochemical parameters such as proline (54.75%), sugar (15.2%), glycine betaine (32.25%), superoxide dismutase (SOD) (49.5%), catalase (CAT) (50.5%), ascorbate peroxidase (APX) (44.9%) and glutathione reductase (GR) (49%) increased as drought stress increased. Metabolite analyses of, for example, MDA (malondialdehyde) content (30.5%), total anthocyanin (36.3%), flavonoid content (26%) and phenolic content (29.5%) increased as drought progressed. We also performed protein profiling of the two varieties using SDS-PAGE (sodium dodecyl-sulfate polyacrylamide gel electrophoresis) to differentiate the expression analysis of the two varieties.