Cold Responses Related to Abscisic Acid, Gibberellin and Indole Acetic Acid and Non-Enzymatic Antioxidants in Chickpea

Abstract

Cold response in plants is mediated by metabolic adjustments of hormones and defense systems which support survival, growth, and crop productivity. Hence, a comparative analysis of metaboliteschangewas conducted in conjunction with oxidative damages in two chickpea (Cicer arietinum L.) genotypes differing in cold-tolerance (Sel96th11439 and ILC533) during coldstress (4°C). In sensitive genotype, cold stress increased H₂O₂ and MDA contents by 47 and 57%, respectively, without any significant changes in tolerant genotype. During stress, unlike the tolerant genotype, the growth of sensitive genotype was markedly inhibited (by 11%) compared to control conditions. During the initial stages of cold responses, ABA content in tolerant genotype reached its peak, showing 77% increase 3 days post stress (dps), whereas the sensitive genotype showed 20% raise 6 dps. Gibberellin (GA) content in the tolerant genotype was 16% higher than the sensitive genotype 1 dps. Compared to control conditions, indole acetic acid (IAA) content attained its maximum level in tolerant and sensitive genotypes at 1 and 6 dps, respectively. 15% increase in phenol compoundsin tolerant genotype was concomitant with heightened antioxidant capacity, as well as increased in flavonoid and anthocyanin contents by 46, 75 and 200% respectively. At 6 dps, a significant increase in transcript levels of chalcone synthase (15.3-fold), phenylalanine ammonia-lyase (3.5-fold), and DELLA (4.2-fold) genes were observed in tolerant genotype at 6 dps. It can be concluded that ability to develop defense responses towards cold stress was related to integrating time-dependent co-regulation patterns of hormone-metabolites with effective stability of plant pigments and growth.