Trehalose-Cytokinin Interplay in Wheat (Triticum aestivum L.) Carbohydrate Metabolism for Drought Resilience

The current study was carried out to study the changes in activities of carbohydrate metabolizing enzymes under drought stressed wheat (Triticum aestivum L.) (HD2967, PBW660 and WH1105) genotypes and how their regulation was maintained by exogenously applied cytokinins (kinetin and benzyl adenine) and trehalose: an osmoprotectant. Alterations in contents of various sugars (total soluble sugars, reducing sugars and non-reducing sugars) were recorded under control and drought stressed crop plants on foliar application of cytokinins and trehalose at vegetative and flag leaf stages. Drought stress significantly increased total soluble sugars (1.2, 1.4 folds), reducing sugars (1.1, 1.3 folds), non-reducing sugars (1.2, 1.5 folds) and sucrose content (1.3, 1.2 folds) at both vegetative stage and flag leaf stage respectively. Carbohydrate metabolizing enzymes viz., sucrose phosphate synthase (1.2 folds), acid invertase (1.1 folds) and sucrose synthase (1.4 folds) were significantly upregulated under drought stressed plants at flag leaf stage. However, the osmoprotectant mitigated the effect by lowering the enzymatic activities in treatments (T3-T6), T4 treatment (Drought + Kn(40g)+ Tre (1.5mM) had the most promising mitigating effect against drought stress at both the stages. A significant negative correlation was observed between grain yield and sugar metabolizing enzymes, specifically SPS (r = -0.70), SS (r = -0.67), and sucrose content (r = -0.70), during the vegetative stage. Moreover the acuteness of the grain yield with the starch content in loading plot indicates the regulation of sugar metabolism that underwent modifications in presence of exogenous PGRs (trehalose, kinetin and benzyl adenine) that leads to significant increase in starch content that ultimately enhances grain yield of wheat.