Genome-Wide Analysis of the PYL Gene Family in Betula platyphylla and Its Responses to Abiotic Stresses

Abscisic acid (ABA) is a key phytohormone that participates in various plant biological processes, such as seed germination, senescence, stomatal movement, and flowering. In the ABA signal transduction pathway, Pyrabactin Resistance 1 (PYR1)/PYR1-Like (PYL)/Regulatory Component is the core module for ABA perception. In this study, a total of 12 PYL family members were identified in birch (<i>Betula platyphylla</i> Suk.) from a genome-wide range that can be divided into 3 subgroups according to their evolutionary relationships. The physiochemical properties of the 12 <i>BpPYL</i>s were characterized, and the members of the same subgroups share more similar exon-intron and motif patterns. The results of synteny analysis showed two syntenic gene pairs within BpPYL family members and 12, 8, 19, and 6 syntenic gene pairs between <i>BpPYL</i>s and <i>AtPYL</i>s, <i>OsPYL</i>s, <i>PtPYL</i>s, and <i>ZmPYL</i>s, respectively. Multiple <i>cis</i>-acting elements were identified in the promoters of <i>BpPYL</i>s, including stress response, phytohormone signaling, and growth and development. The results of GO and KEGG enrichment analysis showed that <i>BpPYL</i>s were enriched in the pathways mainly related to ABA signaling and cell communication. The results of RT-qPCR verified the expressional responses of <i>BpPYL</i>s to ABA, salt, and PEG treatments. Furthermore, the positive roles of <i>BpPYL3</i> and <i>BpPYL11</i> were proven by using salt-tolerant yeast transformation. This study provides a reference for research on ABA signal transduction and forest tree responses upon abiotic stresses.