Genetic Transformation Of Potato With 3GT Gene

The potato (Solamtm tuberosum L.) is a major food crop and ranks fourth in world crop production after wheat, maize and rice. Potato tubers are multiplicative organs as well as product organs, of which the skin has different colours, e.g. white, yellow, red and purple. It has been known that the colour of potato tubers is attributed to the accumulation of anthocyanins. Several recent studies reported that anthocyanin has potential health benefits to human, such as antioxidization, Antimutagenic and anti-tumor.3-O-glucosyltransferase (3GT) is a main gene in the pathway of anthocyanin biosynthesis. It catalyzes the transfer of the glucosyl moiety from UDP-glucose to the 3-hydroxyl group of anthocyanidins, producing the first stable anthocyanins. In this research, it is new attempt to promote anthocyanin biosynthesis in potato tubers by introducing 3GT gene. The results are as follows:The internodes of cultivar Desiree were used as explants in the experiment. The explants were pre-cultured for two days in darkness, then infected with prepared Agrobacterium for 5-10 min, and co-cultivated above for 2 days in the dark. After infection, explants were screened on MGT medium plus 0.03 mg/1 GA3,0.5 mg/1 TDZ, supplemented with cefotaxime (Cef) 200 mg/1 and 50 mg/1 Kan selective medium. Shoots could emerge after induction in light 3-4 weeks later. The regenerated shoots were transferred to selective medium supplemented with 100 mg/1 kanamycin.18 kanamycin-positive plants were obtained, of which 7 plants was PCR positive. Six independent transgenic plants were confirmed by Southern blot analysis. This indicated that 3GT gene has been integrated into the genome of the transgenic plants.Expression level of 3GT in different organs was analyzed by RT-PCR.3GT transcript was higher in tuber and stolon of transgenic plants, compared to wild-type plants. Even there was difference in mRNA level among transgenic plants.The colour of transgenic plant tubers was observed at 40 d and 80 d after transplanting. A difference in tuber colour was found between transgenic plants and wild-type plants, the transgenic plant tubers appeared red while wild-type tubers yellow. Further analysis on anthocyanin content showed that it was 3.3 times in number 5 transgenic tubers than in wild-type tubers. In addition, tuber number per plant and starch content in transgenic plants increased but plant height had decreased.