Genome-Wide Identification and Characterization of the MAG2 Gene Family in Medicago sativa

Background/Objectives: Vesicular trafficking mediates the transport of proteins and other cellular components between intracellular organelles. The MAG2 complex serves as a key tethering factor mediating ER-Golgi retrograde vesicle transport, and has been implicated in plant growth, development, and stress responses. Methods: In this study, seven MAG2 family genes were identified in Medicago sativa from the Zhongmu No. 4 reference genome using hidden Markov model searches (HMM) and BLASTP analysis. Results: Phylogenetic analysis assigned four genes to the MAG2 subfamily and three genes to the MAG2L subfamily. Chromosomal distribution and collinearity analyses indicated that segmental duplication potentially contributed to the expansion of the MAG2 family in alfalfa. Gene structure and conserved motif analyses revealed a high degree of conservation among the identified members, with Motif 10 occurring specifically in the MAG2 subfamily. Subcellular localization prediction analysis predicted that four MsMAG2 proteins were localized in chloroplasts, two in the nucleus, and one in the peroxisome. Analysis of promoter sequences identified numerous cis-regulatory elements associated with responses to hormones, light, and environmental stress, suggesting that MsMAG2 genes may participate in plant development and environmental adaptation. Furthermore, genome-wide association analysis identified MsMAG2L2 that can be associated with tillering. Conclusions: These results provide a comprehensive genome-wide characterization of the MAG2 gene family in alfalfa and establish a basis for further investigating the functional associations of MsMAG2L2 in branch development.