A NOVEL ABA FUNCTIONAL ANALOGUE B2 ENHANCES SALINITY TOLERANCE IN WHEAT

Salinity stress is considered to be the most damaging type of abiotic stress, with devastating effects on wheat production. Abscisic acid (ABA) is a plant hormone that plays an important role in inducing the plant's response to abiotic stresses. Based on the structures of ABA, pyrabactin (PYR) and coronatine (COR), a target chemical compound, B2, was designed in this study. In a previous study, B2 enhanced drought tolerance in wheat by enhancing the ROS capacity, which was achieved by improving the antioxidant enzymes activity and the osmotic adjustment ability. Furthermore, it had a significant effect on improving photosynthesis and increasing the endogenous hormones in wheat under stress conditions. Two wheat cultivars (Triticum aestivum L.), JIMAI22 (JM22) and SHANNONG12 (SH12), were grown under hydroponic conditions to explore the effect of B2 in mitigating salt stress. The results showed that B2 had a function analogous to ABA, especially at a concentration of 0.1 mu mol.L-1. Under a salinity stress of 150 mM NaCl, treatment with 0.1 mu mol.L-1 B2 increased the leaf water content in both wheat cultivars, improving their photosynthetic efficiency and the antioxidant enzyme activity. Moreover, B2 enhanced the expression level of ABA-responsive genes (TaABAOH2, TaNCED1, and TaAREB3). Furthermore, it enhanced the expression level of salt-responsive genes (TaMYB3R1 and TaERF3). Moreover, B2 also induced the endogenous plant hormone (ABA) signaling pathway, which led to an improvement of the salt tolerance in the wheat cultivars.