Genome-wide identification classification, and expression profiling of LAC gene family in alfalfa

Laccases are ubiquitous in nature, and participate in lignin biosynthesis and abiotic/biotic stress responses in plants. However, as a vital leguminous forage grass, Medicago sativa has rarely been reported regarding systematic studies on its LAC gene family.

To systematically investigate the structural characteristics and evolutionary patterns of the LAC gene family in Medicago sativa, we performed genome-wide identification and comprehensive bioinformatics analysis of the MsLAC family. A total of 156 MsLAC genes were identified and unevenly distributed on 28 chromosomes. These genes displayed highly conserved gene structures and motifs, indicating functional conservation. Cis-element analysis suggested that most MsLAC genes are involved in responses to various abiotic stresses. Collinearity analysis revealed that segmental duplication dominated the expansion of the MsLAC family, with strong conservation observed between alfalfa and other legumes. qRT-PCR analysis further verified the expression profiles of candidate MsLAC genes under drought and salt stress, and revealed the potential roles of several MsLAC members in alfalfa abiotic stress response. This study provides a solid basis for exploring the functions of MsLAC genes under abiotic stress.

A systematic characterization of the MsLAC gene family in Medicago sativa was performed in this study. The results indicated that MsLAC genes might participate in regulating plant growth, development and stress adaptation in alfalfa, which could provide potential candidate genes for future stress-tolerant molecular breeding of alfalfa.