Identification of Pyrabactin resistance 1-like (PYL) genes in Brachypodium distachyon and functional characterization of BdPYL5.

Abscisic acid (ABA) is an endogenous phytohormone that plays an important role in regulating plant growth, development, and stress response. Pyrabactin resistance 1-like (PYR/PYL) proteins are ABA receptors and core components of ABA signalling in plants. This study identified nine PYL genes in the Brachypodium distachyon genome and they distribute on three chromosomes. Phylogenetical BdPYLs were classified into three clades. 81 protein-protein interactions between 9 BdPYLs and 9 BdPP2C proteins were predicted and 66 pairs were verified by yeast two-hybrid assay previously. Relatively, BdPYL genes are expressed in leaves at high level, and ABA and drought regulate their expression. A homologue of Arabidopsis PYL9, BdPYL5 was selected to overexpress in Arabidopsis to characterize its function. In general, overexpression of BdPYL5 enhanced ABA sensitivity and drought tolerance, implying its conserved function. Our study lays the foundation for further functional elucidation of BdPYL genes.