Study On Introduction Of Plant Spermidine Synthase Gene (MdSPDS) Into Potato

Potato is the world’s important economic crops. The potato planting area and yields of our country ranked first in the world. Each ecological region has grown potato in our country,even southern provinces also plant potato in the winter fallow. But the potato cultivars, which are the main varieties in southern district, can’t adapt themselves to low temperature, high humidity and weak light in winter and spring, and are seriously affected the production of potato. Lack of suitably planting varieties in winter crop area is the main factor that restrict the development of potato production in Southern of China. Therefore, selecting new varieties, which possess resistance to low temperature and high photosynthetic efficiency, is one of the main goals of potato breedling of winter crop area in southern district, as it has important realistic and strategic significance for developing potato production of winter crop area in south of China.Polyamines are low molecular weight, aliphatic nitrogenous bases found in all living organisms. It can promote the growth and development of plants, play a role in the regulation of plant stress resistance, help the plant to establish defense mechanism and resist to biotic and abiotic stresses, increase plant adversity resistance.Spermidine synthase is the key enzyme of polyamine biosynthesis. Atlantic and Dongnong303, the main cultivars of southern district in winter crop area, were as materials.They were transformed spermidine synthase gene (MdSPDS),established regeneration system. This study has initially screened excellent transformation lines by comprehensive evaluation of molecular biology, polyamine contents and growth traits of transgenic plants. The main results obtained are as follows:1. By Cef concentration gradient experiment, it has discovered that500mg/L Cef can restrain the growth of Agrobacterium effectively. By Kan pressure screening experiment, it has confirmed that50mg/L Kan is a suitable concentration as selection pressure of inducing callus, differentiation and rooting of both Atlantic and Dongnong303. It has been switched extraneous MdSPDS to stem segments, via Agrobacterium-mediated method, established genetic regeneration system of Atlantic and Dongnong 303,and obtained44and59resistant plants of Atlantic and Dongnong303respectively. Their regeneration rate is15.28%and20.07%respectively.2. By PCR detecion, there are67transformed MdSPDS positive plants, including33positive plants of Atlantic and34positive plants of Dongnong303. Well-grown transgenic plants of Atlantic and Dongnong303were selected for RT-PCR detection. There are11transgenic plants of Atlantic and Dongnong303respectively transcribing MdSPDS.3. By observation of plants appearance morphology, it has found that transformants were superior to untransformants of Atlantic and Dongnong303in the plant height, stem diameter, root length, root number, leaf number, internode number and the number of branches with varying degrees. The results of tuberization experiment have been indicated that majority transformants’yields win out over those of untransformants of Atlantic and Dongnong303, but also some transformants showed the advantage of large tuber rate.4. It has been screened out the comprehensive performance of excellent lines of Atlantic and Dongnong303,They were01-47and02-57.