Genome-Wide Identification and Expression Analysis of the Starch Synthase Gene Family in Sweet Potato and Two of Its Closely Related Species.

The starch synthase (SS) plays important roles in regulating plant growth and development and responding to adversity stresses. Although the family has been studied in many crops, it has not been fully identified in sweet potato and its two related species. In the present study, eight were identified from (), (), and (), respectively. According to the phylogenetic relationships, they were divided into five subgroups. The protein properties, chromosomal location, phylogenetic relationships, gene structure, cis-elements in the promoter, and interaction network of these proteins were also analyzed; stress expression patterns were systematically analyzed; and real-time polymerase chain reaction (qRT-PCR) analysis was performed. starch synthase () were highly expressed in tuber roots, especially starch synthase 1 () and starch synthase 6 (), which may play an important role in root development and starch biosynthesis. At the same time, the genes respond to potassium deficiency, hormones, cold, heat, salt, and drought stress. This study offers fresh perspectives for enhancing knowledge about the roles of and potential genes to enhance productivity, starch levels, and resistance to environmental stresses in sweet potatoes.