Deciphering ABA/PYL gene family in flax: evolutionary analysis, and abiotic stress response

The identified PYL/PYR/RCAR receptor gene family differentially modulates stress-responsive and developmental roles in linseed. This gene family is evolutionarily and functionally conserved in agronomically imperative oilseed crop species. Abscisic acid (ABA) functions as a key phytohormone, exerting significant regulation over diverse cellular activities, notably growth and responses to various environmental stressors. The protonated form of ABA (ABAH) is perceived by intracellular Pyrabactin resistance 1-like (PYR/PYL) proteins, constituting an integral component of the signaling cascade. The PYLs represent one of the largest phytohormone receptor families identified. The receptors have been extensively investigated in numerous plant species. However, the PYL family in oilseed crop species has not been systematically identified at the genome level. This study identified 15 members of the PYL gene family in the linseed, exhibiting a non-uniform distribution across the 15 chromosomes. Based on structural and functional similarities, the phylogenetic analysis divided linseed PYLs (LuPYLs) into three subfamilies. Gene and motif structure analysis of LuPYLs revealed that members of each subfamily share similar gene and motif structures. An evolutionary relationship with PYL members in other oilseed crop species has been established, wherein whole-genome duplication appears to be the primary driving force underlying the expansion of the PYLs. Collinearity segregated PYL genes from all selected species into five distinct clusters, each representing a conserved functional module. The regulation of PYL genes in linseed, including transcriptional analysis of CREs in promoter regions, identification of SNPs, and assessment of miRNA-mediated post-transcriptional regulation, was assessed. Tissue-specific qRT-PCR analysis revealed diverse expression patterns of LuPYL genes, highlighting their roles in plant development and abiotic stress responses. These findings provide valuable insights into how PYL genes contribute to abiotic stress tolerance in flax.