Overexpression of a sour jujube gene ZjPYR1, encoding a putative abscisic acid receptor, increases sensitivity of the stomata and roots to ABA in Arabidopsis thaliana

Abstract

The abscisic acid (ABA) receptor binds to ABA in plants and can activate the ABA signaling pathway to initiate stress resistance. Sour jujube (Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. Chou) is an economic tree crop in North China, which is strongly adapted to drought and salt stress. Here, we cloned and overexpressed the ZjPYR1 gene in Arabidopsis thaliana. After ABA treatment, the accumulation of ZjPYR1 increased significantly, suggesting that ABA may stabilize ZjPYR1 in the plants. Compared with the wild-type, the heterologous transgenic lines showed smaller stomatal openings under ABA treatment and a shorter root length and lower germination rate under ABA and salt treatment. Based on these results, we speculate that the overexpression of ZjPYR1 in A. thaliana effectively enhanced the stress resistance of the plants, and furthermore, that ZjPYR1 is a putative ABA receptor in sour jujube that increases plant adaptability to drought and salt stress. We report that ZjPYR1, like most ABA receptors in A. thaliana, is involved in mediating plant responses to ABA, such as stomatal closure and root length.