Establishment Of Transgenic System Of Potato Mediated By Agrobacterium Tumefaciens

Potato is one of the most important crops of the world. But serious diseases have greatly hampered the development of the potato industry. The enhancement of consumer's demand for good quality potato and the coming challenge after entering WTO also bring out potato researchers new objectives. In conventional sexual hybridization of potato, the segregation of homo-tetraploid of potato cultivars made it very time consuming and low efficiency in improving characters of the potato. The application of genetic transformation is a promising strategy for potato genetic improvement, with which the desire gene could be efficiently introduced into the genome without altering the good characters and identity of the cultivars.Agrobacterium-mediated transformation has been used worldwide for introducing foreign genes into different potato cultivars. However, many researches showed that the transformation efficiency is genotype-dependent. It is necessary, therefore, to establish an efficient protocol of transformation according to the specific conditions of independent laboratory.In this research, three kinds of explants, stem, leave and leafstalk, from four genotypes were used for the regeneration experiment. An efficient and stable regeneration system of potato was established. In this system, the stem promoted plant regeneration more efficiently than the other explants. The optimized combination of hormones for regeneration of callus was 1mgL-1 BA, 0.1mgL-1 NAA and 0.1mgL-1 GA. The combination of hormones for regeneration of shoots was 1mgL-1 BA and 3mgL-1 GA. Plantlets of three genotypes were obtained.Effects the period of preculrure, bacterial infection and co-cultivation on the transgenic efficiency were investigated. The results showed that the optimized period for preculture was 2 days, for bacterial infection was 5 minutes, and for co-cultivation was 2 davs.The transformation efficiency could reach as high as 13.89% with stem, but not stable enough. The transformation efficiency with in vitro-grown microtuber explants could reach 17.02% stably. By combining the best treatments, the protocol with in vitro-grown microtuber was better because of its high transformation rates and simple process.