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 (Betula platyphylla Suk.) from a genome-wide range that can be divided into 3 subgroups according to their evolutionary relationships. The physiochemical properties of the 12 BpPYLs 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 BpPYLs and AtPYLs, OsPYLs, PtPYLs, and ZmPYLs, respectively. Multiple cis-acting elements were identified in the promoters of BpPYLs, including stress response, phytohormone signaling, and growth and development. The results of GO and KEGG enrichment analysis showed that BpPYLs were enriched in the pathways mainly related to ABA signaling and cell communication. The results of RT-qPCR verified the expressional responses of BpPYLs to ABA, salt, and PEG treatments. Furthermore, the positive roles of BpPYL3 and BpPYL11 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.