Increased Abscisic Acid Sensitivity And Drought Stress By Overexpression of Abscisic Acid Receptors In Arabidopsis Thaliana

Abstract Abscisic acid (ABA) is a key plant hormone that regulates plant growth development and stress response. ABA is recognized and bound by ABA Receptor PYR/PYL/RCAR (referred to as PYLs). However, little is known about the PYLs gene family in Populus euphratica. Here, we identified 12 PYLs in P. euphratica and named PePYL1-12. Phylogenetic analysis divided the 12 PePYLs into three subfamilies. Subcellular localization showed that PePYL2, PePYL4, PePYL5, PePYL6, and PePYL9 were located in the cytoplasm and nucleus, PePYL10 localized in the nucleus. The promoter of 12 PePYLs contains hormones- and abiotic stress-related cis-acting elements. Moreover, ABA and drought significantly up-regulation the expression of PePYL6 and PePYL9. To study the performance of PePYLs under ABA and drought stress, we generated transgenic Arabidopsis plants overexpressing PePYL6 and PePYL9. Compared with wild type, transgenic Arabidopsis enhanced ABA sensitivity during seed germination and root growth, improved water use efficiency and drought resistance. Taken together, our results confirmed that PePYL6 and PePYL9 play a positive role in ABA-mediated stress responses in P. euphratica.