Genome-wide identification, classification and expression analysis of laccase family members in Solanum lycopersicum

Laccase, a copper-containing polyphenol oxidase, is integral to plant growth and development, primarily due to its involvement in lignin and flavonoid biosynthesis, as well as its role in mediating plant responses to diverse biotic and abiotic stresses. Despite its importance, a comprehensive and systematic analysis of the laccase gene family in tomato has not been conducted until now. This study identifies eighteen laccase genes, unevenly distributed across seven chromosomes, within the tomato genome. Phylogenetic analysis categorizes these eighteen SlLACs into five distinct groups, corresponding to the established groups in Arabidopsis. Motif analysis indicates the presence of ten conserved motifs within the SlLACs. Gene duplication analysis reveals collinearity between the eighteen SlLACs and LAC genes in Arabidopsis, eggplant, and potato. Furthermore, cis-regulatory element analysis suggests that numerous SlLACs may be implicated in tomato morphogenesis, flavonoid biosynthesis, and various stress and growth processes. Expression analysis suggests that certain SlLAC genes may function in different tomato organs and potentially participate in diverse stress responses via hormone signaling pathways. This study contributes to elucidating the physiological roles of SlLAC family genes in tomatoes and may offer valuable genetic resources for tomato breeding programs.