Analysis And Evaluation Of Tuber Dormancy And Sprouting Characteristics Of Transgenic Potatoes With PPase Gene

The characteristics of potato tuber dormancy and sprouting could be controlled by regulating co-substrate (inorganic pyrophosphatase) in the sugar metabolism. In order to obtain new transgenic potato germplasm with prolonged or shortened dormancy period, the physiological and biochemical indexes were measured and tuber dormancy and sprouting characteristics were analyzed and evaluated for transgenic PPase gene potatoes. The main results as following:1. Economical characteristics of the transgenic potato plants in the greenhouse were measured, the results showed that the plant height was increased, and the tuber number was decreased for the sense transgenic plants of potato cultiva Gannongshu 2. The plant height was decreased, the tuber number was increased, and tuber weight was decreased for the antisense transgenic plants, which compared with the untransgenic plants. There was no significant difference for the sense transgenic potato plants of potato cultiva Favorita compared with the untransgenic plants, howerer, there was significant difference between the sense transgenic potato plants and the untransgenic plants for plant height.2. PPase activity and Pi content were measured in the transgenic and the wild potato plants, the results showed that for the transgenic plants of potato cultivars Gannongshu 2 and Favorita which were driven by constitutive expression promoter CaMV 35S, the PPase activity and Pi content in the leaves, stems and growing tubers of the sense transgenic plants were improved, and there were reduced in the antisense transgenic plants compared with the untransgenic plants. For the transgenic plants driven by the low temperature-induced expression promoter rd29A, PPase activity and Pi content veried slightly in the leaves, stems and growing tubers, but there was a significantly difference for the microtubers stored at 4℃and 25℃compared with the untransgenic plants.3. The content of starch and soluble sugar were assayed in the transgenic and untransgenic minitubers under different storage condition, the results demonstrated that for the transgenic plants driven by CaMV 35S promoter, starch content was not varied in the sense transgenic minitubers, while sugar content was increased significantly, and starch and sugar content was decreased in the antisense transgenic minitubers compared with the untransgenic minitubers. For the transgenic plants driven by rd29A promoter, starch content in the growing minitubers was not changed, while starch and sugar content varied significantly in the transgenic minitubers stored at 4℃and 25℃compared with the untransgenic minitubers.4. The results from statistics and analysis of dormancy and sprouting preiod of the transgenic minitubers stroed at different storage condition showed that the sprouting time of the sense transgenic minitubers was 2 to 3 weeks earlier than the untransgenic minitubers, while it was 2 to 3 weeks late than the untransgenic minitubers.