Molecular Cloning of Sucrose Isomerase Gene and Agrobacterium-Mediated Genetic Transformation of Potato (Solanum tuberosum L.) Plants

Potato (Solanum tuberosum L.) is one of the most common and important food sources on the planet, and they essential as a staple dietary item for much of the world's population. Potatoes contain carbohydrates, which lead to high blood sugar. Palatinose (isomaltulose, 6-O-alpha-D-glucopyranosyl-D-fructose) is a functional isomer of sucrose its non-cariogenicity low calorific value and it is an ideal sugar substitute to use in food production. The sucrose isomerase (palI) gene that is obtained from Erwinia rhapontici is one of the most common genes that can convert sucrose into palatinose. In present study, pQE-30- palI construct was succeffuly transformed and expression into E. coli. Sucrose isomerase (palI) gene was cloned and overexpressed into a plant expression vector pBinAR- palI contains sucrose isomerase gene (palI) fused to proteinase inhibitor II signal sequence under CaMV-35S promoter and Octopine Synthase (OCS) terminator. Expression of the protein was verified by western blot assay. Also, expression of the palI gene within the apoplast of transgenic tubers under control of a tuber-specific patatin class I B33 promoter instigated quantitative conversion of sucrose into palatinose. Tuber extracts from potato cv. Désirée were analyzed for their soluble carbohydrate composition using HPLC.