Genome-wide identification, phylogeny analysis, expression profiling, and determination of protein-protein interactions of the LEUNIG gene family members in tomato

Members of the LEUNIG gene family have recently emerged as key players in gene repression, affecting several developmental mechanisms in plants, especially flower development. LEUNIG proteins function via recruiting adaptor SEUSS proteins. Nevertheless, no systematic studies on the LEUNIG and SEUSS gene families have been undertaken in tomato (Solanum lycopersicum, a fleshy fruit-bearing model plant, belonging to the Solanaceae family). Here, we present the results of a genome-wide analysis of tomato LEUNIG and SEUSS genes. In our study, we identified three SlLUG and four SlSEU genes. All three SlLUG full-length proteins contained the LEUNIG canonical domains (LUFS and two WD40 repeats), and the four full-length SlSEU genes contained the Lim-binding domain. All the members of the SlLUG and SlSEU family proteins were localized to the nucleus. All the SlSEU and SlLUG genes were detected in the tomato tissues tested. Expression analysis showed that the SlLUGs and SlSEUs exhibited tissue-specific expression, and that they responded to exogenous plant hormone and stress treatment. Protein-protein interaction analysis showed that only SlLUGs, but not SlSEUs, interacted with SlYABBY. Only a weak interaction between SlLUG1 and SlSEU3 was observed among all the SlLUG and SlSEU proteins. Taken together, these findings may help elucidate the roles played by SlLUG and SlSEU family members in plant growth and development.