Abstract
BACKGROUND: The Pyrabactin resistance 1-like proteins (PYR/PYL/RCAR) protein plays a critical regulatory role in the ABA signal transduction pathway as a direct receptor of abscisic acid (ABA). Although PYL genes have been identified in a variety of plants, the evolution and structural characteristics of these genes in alfalfa (Medicago sativa) are largely unknown. Therefore, a comprehensive bioinformatics analysis of the PYL gene family was performed in this research. RESULTS: The results indicated that 41 MsPYL genes were unevenly distributed across 24 chromosomes. According to gene structure, conservative features, and phylogenetic relationships, MsPYL proteins can be divided into 6 groups, all of which have PYR/PYL/RCAR domains, and MsPYL proteins are relatively small (molecular weight 19.59 kDa to 25.31 kDa). MsPYL genes contains cis-acting elements that has functions in plant growth and development, hormone regulation, and stress response. Furthermore, transcriptome data showed that drought stress affected the MsPYL genes' expression levels in alfalfa. Tissue specificity analysis revealed that all MsPYL genes exhibited varying responses to drought, abscisic acid (ABA), salicylic acid (SA), and indole-3-acetic acid (IAA). Additionally, all MsPYL genes were expressed to different extents in both the aboveground and underground tissues following stimulation. They were induced by IAA, ABA, and SA from 6 h to 12 h, and ABA induced MsPYL4 most significantly at the 12 h mark. MsPYL4, MsPYL8, MsPYL11, and MsPYL19 were expressed only after hormone treatment. CONCLUSIONS: The results of this study indicate that the MsPYL genes are closely related to stress response and provide new candidate genes for further exploration of MsPYL genes function and improvement and innovation of drought-resistant alfalfa germplasm.