Genome-wide characterization of the cellulose synthase gene superfamily in Solanum lycopersicwn

The cellulose synthase gene superfamily, which includes the cellulose synthase (CesA) and cellulose synthaselike (Csl) gene families, plays a vital role m the biosynthesis of cellulose and hemicellulose in plants. However, these genes have not been extensively studied in tomato (Solanum lycopersicum), a model for Solanaeeae plants and for fleshy fruit development. Here, we identified and systematically analyzed 38 CesA/Csl family members that contained cellulose synthase domain regions, and categorized their encoded proteins into 6 subfamilies (CesA, CsIA, Cs1B, COD, Cs1E, and Cs1G) based on phylogenetic analysis. Most CesA/Cs1 genes from tomato are closely related to those from Arabidopsis, but the families have distinct features regarding gene structure, chromosome distribution and localization, phylogeny, and deduced protein sequence, indicating that they arose via different evolutionary process. Furthermore, expression analysis of CesA/CsI genes in different tissues at various developmental stages showed that most CesAs were constitutively expressed with differential expression levels in various organs; three CsID genes were expressed specifically in flowers, and four CesA and five Csl putative genes were preferentially expressed In fruits. Our results provide insight into the general characteristics of the CesA/CsI genes in tomato, and lay the foundation for further functional studies of CesA/Csl genes in tomato and other So/anaceae species.