STUDY ON REGULATION OF 5′ FLANKING REGIONS OF GRANULE BOUND STARCH SYNTHASE GENE OF POTATO

Binary vectors were constructed by fusing 0.4, 0.8, 1.6, and 2.9 kb 5′ flanking regions of GBSS gene with GUS (β glucuronidase). Transient GUS expression was observed in in vitro tuber slices bombarded with 0.8 kb GBSS GUS construct. These constructs were then transferred into potato ( Solanum tuberosum L. cv. Desiree) via Agrobacterium tumefaciens transformation. Transgenic potato plants were confirmed by X Gluc staining and PCR. Using in vitro tuberization system, GUS expressions were assayed with fluorescence, it was shown that 0.8, 1.6 and 2.9 kb GBSS GUS expressions were higher than 0.4 kb GBSS GUS. 1.6 and 2.9 kb GBSS GUS expressions were about 2 to 10 folds higher in tubers than in stems. In cultured shoots, GBSS GUS expression could be induced by increased sucrose concentration but inhibited by light.