Sucrose, the main end product of photosynthesis, can be readily transported to non-photosynthetic tissues to support plant growth or for starch synthesis. Invertase or sucrose synthase converts sucrose to fructose 6-phosphate (Fru(6)P), which can, in turn, serve as a substrate for the starch biosynthesis pathway. Glucose 6-phosphate isomerases catalyze the conversion of fructose 6-phosphate (Fru(6)P) to glucose 6-phosphate (G6P). In addition, Fru(6)P can be used in the glycolysis pathway.
