In silicoMechanistic Study of Abscisic Acid (ABA) Mediated Drought Tolerance in Crops

Drought is one of the major environmental stresses that produces adverse effects on plants. Vast areas of agricultural land is susceptible to drought. Drought induced yield loss of crops has negative effects on the economy of a country. Among phytohormones, Abscisic Acid (ABA) induces abiotic stress tolerance in plants, and directs a complex regulatory network involving multiple transporters, up-regulation of ABA biosynthesis genes and various signalling pathways that enable plants to withstand low water availability. The current study was designed to understand ABA synthesis, its transport across the plant during stress and its mechanism to induce stomatal closure by using different in silico tools, because the complete ABA mediated drought tolerance has not yet been reported. In the current study, seven transporters, four ABA biosynthesis enzymes, deconjugation enzyme and a core complex of ABA signalling was verified through Modeller 9.10 and Molecular Operating Environment (MOE).The Intel [R] Xenon [R] CPU-E5420 @ 2.50 GHz system with 4 GB of RAM and the 11.4 (X 86_64) operating system was used for molecular docking. Protein-ligand interactions were analysed by the LigPolt feature of MOE. Docking studies helped to understand the behaviour of ABA biosynthesis enzymes, ABA transporters and ABA core complex, which in turn helps to comprehend the whole mechanism of ABA synthesis in plants during drought stress. Computational models of AtABCG11, AtBG1, AtABCG12,AtABCB14,AtABCG22,AtABCG25,AtABCG32, AtABCG40, NCED, ABA2 and AAO were used for docking. Docking analysis has shown promising results for all the models, except AtABCG11 and AtABCG12. Residues of AtABCG11 and AtABCG12 did not show binding with the ABA, as these transporters are involved in cuticle formation. Findings of this study will strengthen the work on ABA drought tolerance in plants and help to produce drought resistant crops globally.