Genome-wide identification, structural characterization and gene expression analysis of the LEA_2 gene family in faba...

Late Embryogenesis Abundant Protein 2 (LEA_2) plays critical roles in plant abiotic stress adaptation and developmental regulation. Faba bean (Vicia faba L.) is an important global crop, but its productivity is severely limited by abiotic stress. However, the LEA_2 gene family, which is critical for stress adaptation, remains poorly characterized in this species.

In this study, we performed the first genome-wide identification of LEA_2 genes in faba bean, identifying 41 members (VfLEA_2-1-VfLEA_2-41) phylogenetically classified into seven subfamilies (Groups 1-7). Chromosomal distribution analysis localized 40 VfLEA_2 genes across seven chromosomes, while VfLEA_2-41 resided on a contig. Tandem (4 pairs) and segmental (8 pairs) duplication events were identified as key drivers of family expansion, with collinearity analysis indicating closest evolutionary relationships to Trifolium repens (white clover) among six legume species. Expression profiling demonstrated tissue-specific patterns, with VfLEA_2-4/VfLEA_2-5 (pods), VfLEA_2-15/VfLEA_2-38 (seeds), and VfLEA_2-21/VfLEA_2-32 (stems) showing preferential expression during development. Furthermore, VfLEA_2 genes exhibited dynamic responses to ABA, MeJA, SA, and abiotic stresses (drought, cold, salt), with rapid induction (3-6 h post-treatment) and stress-specific expression kinetics. These findings systematically elucidate the molecular evolution, structural features and functional differentiation of VfLEA_2 genes, providing a foundation for leveraging these candidates in faba bean breeding to enhance stress resilience and yield stability.

This study represents the first investigation focusing on an important crop species, addressing practical challenges to its survival, and targeting crucial proteins influencing plant growth. By integrating bioinformatics with molecular biology, we systematically identified the LEA_2 gene family in faba bean and conducted in-depth analyses of their physicochemical properties, evolutionary relationships, and expression patterns. This work establishes a theoretical foundation for future research on the functional roles of faba bean LEA_2 genes in plant growth, development, and environmental adaptation.