Identification, evolutionary diversification, and stress response roles of SmLACSs in Salix matsudana

Understanding the mechanisms underlying plant stress tolerance is crucial for improving plant resilience, particularly under challenging environmental conditions. This study investigates the role of long-chain acyl-CoA synthetases in Salix matsudana (SmLACSs), focusing on their evolutionary relationships, functional characterization, and response to environmental stresses. Through a comprehensive analysis, 25 SmLACSs were identified, classified into seven distinct clades, with Clade VII representing a newly discovered subfamily in willow. Evolutionary analysis revealed that segmental duplication and whole-genome duplication were key mechanisms for the expansion of SmLACSs. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis further indicated that SmLACSs play a role in lipid metabolism, cuticle formation, and stress response pathways. Using RNA-seq and qRT-PCR, differential expression patterns of SmLACSs under salt or submergence stress were observed, highlighting their contribution to stress tolerance, particularly in maintaining cell membrane integrity and lipid homeostasis. These findings provide valuable insights into the roles of SmLACSs in willow’s resilience, and offer potential targets for improving stress tolerance in plants.