Comprehensive analysis of the LTPG gene family in willow: Identification, expression profiling, and stress response

The non-specific lipid-transfer proteins (LTPs), particularly the glycosylphosphatidylinositol (GPI)-anchored LTPs (LTPGs), play pivotal roles in various plant physiological functions, particularly in the context of environmental stress adaptation. Despite their importance, LTPGs in willow (Salix matsudana), an ecologically and economically important species, remains poorly understood. This study systematically identified and characterized 30 SmLTPGs in the S. matsudana genome, classifying them into four distinct classes based on phylogenetic analysis. Tandem and segmental duplications in SmLTPGs highlighted their evolutionary diversification. Expression profiling revealed dynamic changes across various willow varieties and significant roles for SmLTPG24/25 and SmLTPG05 in salt and submergence stress responses, respectively. Additionally, co-expression analysis indicated a potential collaboration between SmLTPGs, fatty acid desaturases (FADs), and long-chain acyl-CoA synthetases (LACSs) in FA biosynthesis, contributing to resilience against salt and submergence stresses. This research provided critical insights into the molecular mechanisms underlying willow adaptability to environmental stresses and established a foundation for future applications in stress-tolerant willow breeding and management.