Pho1a gene fragment variability in tuber-bearing and nontuber-bearing potato species (Solanum subgenus Potatoe) and S. tuberosum L. cultivars

Starch is the main metabolite in potato tubers. Therefore structure and functional analysis of starch metabolism genes are of fundamental and applied interest. The final starch amount in sink organs (fruits, seeds and tubers) depends not only on the amylose and amylopectin synthesis, but also on the catabolic enzymes activity. Proteins that participate in starch biosynthesis are rather well studied, while the starch degradation reactions are not fully understood. To date, more data on the crucial role of starch-phosphorylases in this process have been reporting. Starch phosphorylases are widespread among plant species, but the coding genes structure and genetic diversity remain unclear. In potato tubers starch is cleaved by L-form of starch phosphorylase encoded by the Pho1a ( STP23 ) gene. In the current work Pho1a gene fragment (exon II-exon IV) variability was analyzed for the first time in 15 wild and 81 cultivated potato accessions. The chosen gene fragment corresponds to the regulatory part of the glycosyltransferase domain and comprises glucose-6-P binding site, pyridoxal phosphate cofactor binding site and active site (glucose binding)...