Phylogenetic and Expression Analysis of the Sucrose Synthase and Sucrose Phosphate Synthase Gene Family in Potatoes.

Sucrose synthase (SUS) and sucrose phosphate synthase (SPS) are essential in plant sucrose metabolism. The potato is an important crop worldwide, but systematic analyses of the and gene families in potatoes are still lacking. Ten sucrose metabolism-related genes were identified in this study. The and could each be split into three subgroups through phylogenetic analysis. was the most highly expressed gene in different developmental tissues. Ka/Ks analysis showed that and were subjected to more-significant homozygous selection pressure. Our cis-acting element analysis of the and promoter sequences showed four elements: defense- and stress-responsive, hormone-responsive, light-responsive, and transcription factor elements. The expression of and genes was found to be regulated by circadian rhythm. In the treatments of 1% to 5% sucrose, glucose, and fructose, the expression of and family genes was enhanced by sucrose, but inhibited at high-glucose and fructose concentrations. This study identified six and four genes and analyzed their gene structure, conserved motifs, chromosome position, promoter elements, phylogenetic tree, and tissue-specific expression patterns. Our results will motivate more research into the biological process underlying the genes of sucrose metabolism in potatoes.