Genome-Wide Identification and Expression Analysis of the Sucrose Synthase Gene Family in Sweet Potato and Its Two Diploid Relatives.

Sucrose synthases (SUS; EC 2.4.1.13) encoded by a small multigene family are the central system of sucrose metabolism and have important implications for carbon allocation and energy conservation in nonphotosynthetic cells of plants. Though the family genes () have been identified in several plants, they have not been explored in sweet potato. In this research, nine, seven and seven were identified in the cultivated sweet potato (, 2 = 6 = 90) as well as its two diploid wild relatives (2 = 2 = 30) and (2 = 2 = 30), respectively, and divided into three subgroups according to their phylogenetic relationships. Their protein physicochemical properties, chromosomal localization, phylogenetic relationship, gene structure, promoter -elements, protein interaction network and expression patterns were systematically analyzed. The results indicated that the gene family underwent segmental and tandem duplications during its evolution. The were highly expressed in sink organs. The especially , and might play vital roles in storage root development and starch biosynthesis. The could also respond to drought and salt stress responses and take part in hormone crosstalk. This work provides new insights for further understanding the functions of and candidate genes for improving yield, starch content, and abiotic stress tolerance in sweet potatoes.