Role of abscisic acid receptor PYLs in mediating stress resistance of Zostera marina

Abscisic acid (ABA), a pivotal plant hormone, regulates seed dormancy and germination, promotes leaf senescence and abscission, while enhancing plant stress resistance. The pyrabactin resistance 1-like (PYR/PYL) proteins function as core regulators in the ABA signaling transduction pathway. Despite Z. marina has ecological and economic benefits, there has been no research on its ZosmaPYL family so far. This study identified six ZosmaPYLs, all of which contain conserved ABA-binding gate and latch domains. Promoter analysis revealed ABA-responsive cis-elements in the ZosmaPYLs. Differential expression patterns of ZomaPYLs were observed across various tissues and under ABA stress conditions. Molecular simulations and surface plasmon resonance (SPR) verified the affinity between ZosmaPYLs and ABA, revealing that six ZosmaPYLs exhibit distinct affinities for ABA. Protein-protein interaction (PPI) network analysis revealed ZosmaPP2C3/4 interactions with all ZosmaPYLs, whereas yeast two-hybrid (Y2H) assays validate ABA-dependent binding between specific ZosmaPYLs and ZosmaPP2C3/4. The transcriptome data revealed that ABA stress induces organ-specific transcriptional remodeling in Z. marina leaves (photosynthesis) and roots (transport or antioxidants), MYB and NAC transcription factors (TFs) target-regulated ZosmaPYLs expression. These results suggest that ZosmaPYLs serve as a central regulator that connects ABA perception with stress-responsive pathways in Z. marina.