[Starch metabolism in potato tubers].

Sucrose is a substrate for starch biosynthesis, unloaded symplastically into the developing potato tubers. Sucrose is converted to glucose-6-phosphate in the cytosol and exported into the amyloplasts. Starch may be degraded either hydrolytically or phosphorolytically. Glucose and maltose are products of hydrolytic starch breakdown in the sprouting tubers. Glucose phosphates are products of the phosphorolytic activity, metabolized to glucose and fructose in cold-stored tubers. Development of molecular tools for assaying potato gene function provide opportunities to receive genetic progress in the sugar-starch potato breeding.