Agrobacterium-mediated Transformation Of Potato (Solanum Tuberosum) With AtCIPK23 Gene And Its Response Of Potassium Nutrition Efficiency

AtCIPK23, a protein kinase, interacting with two calcineurin B-like protein (CBL1/9), is crucial for the response to low-K+stress in Arabdopsis. Under low-K+ conditions, the kinase CIPK23 interacts with and functions with CB1/CBL9, providing a molecular link between intracellular calcium fluctuations and the regulation of transpiration and mineral nutrition. Both CBL1 and CBL9 can recruit CIPK23 to the plasma membrane, suggesting that plasma membrane localized target proteins, including the AKT1 potassium channel by protein phosphorylation. PCR, Southern blot and RT-PCR analysis indicated that the AtCIPK23 gene has been integrated into genome of potato and transcribed and expressed in transgenic potato plants. When cultured in low-K+, the dry weight of transgenic potato T15, T21 and T23 were 40.4%,64.6% and 41% higher than that of the non-transgenic line respectively, while the K+content per plant showed 34.8%,70.9% and 50.6% increases in transgenic lines. For K+uptake among the plants tested, compared with nontransgenic potato, the Km and Cmin of transgenic lines T15, T21 and T23 decreased by 13.9%,21.3% and 27.8%; 19.9%,41.9% and 38.3% respectively, but the Vmax increased by 21.6%,54.5% and 17%. Morphological observation of the transgenic plants showed that the characteristics of them were normal and no abnormal transgenic plants were observed in the experiments. Several independent transgenic potato lines exhibited sustained plant growth, less leaf chlorosis and more developed root system. These results indicated that the expression of AtCIPK23 confer enhanced low-K+tolerance in potato. With these results, it became possible to develop potato varieties resistant to low-K+by transformation with AtCIPK23 gene, and aslo it demonstrated nutrition genetic engineering for potato and insect-resistant and virus-resistant genetic engineering have the same feasibility. To increase potassium-efficiecy of crops by genetic engineering and traditional breeding method was the most promising way to overcome the potassium deficiency for sustainable crop production.