Establishment Of High-effective Gentic Transformation System In Indica Rice

Rice is one of the most important grain crops in the world.It has been reported that about 40% of the world's people take it as their staple food.Simultaneously, rice is also a modle plant of the monocotyledon genomen and functional studies ,which is only inferior to wheat in china.In recent years, genetic transformation of rice is playing more and more important role in improving rice's varieties, detecting the gene function and creating a mutant .With further development of the research in molecular biology,the techniques and methodologies of gene isolation,cloning and DNA recombination have become more and more mature, now genetic transformation has become a useful method in rice genetic improvement.The rice gentic transformation main uses Agrobacterium-mediated transformation system and particle bombardment.Agrobacterium-mediated transformation system is imitated the natural vector systems.Comparing to other transformation methods, it has unique advantages,so it is widely uesd in rice research. However,genetic transformation of rice has increased complexity and randomness since there exists wide genetic diversity among rice varieties and response to Agrobacterium-mediated genetic transformation deeply depends on rice geotype.Especially,there is much difficulty in Indica rice transformation.Although some examples have been reported to make successful genetic transformation of Indica rice,they were limited to special varieties and transgenic frequency was very low.So far,they have been not found a common transformation techniques which is suitable for all Indica varieties.Therefore ,in order to establish stable and high efficient transformation system we must solve many problems through further investigation. Among all rice varieties,more than 80% are Indica and the main rice varieties planted in most south area provinces of China are Indica rice ,so it is having social and economic significance to make genetic improvement of Indica rice. Multi-resistant transgenic rice is carried out and summarized as following:1,The paper analyses the main factors of Agrobacterium-mediated transformation. From the paper we can reaveal that the concentration of Agrobacterium between 0.3-0.5 is most favorable for infection, with additional oscillations the result will be better.At the same time ,It will improve the the conversion rate by not adding AS in the Agrobacterium and the co-culture medium .After that we also found that adding some Vitaminization C in the ddH2O will have a good function in preventing callus brown; It also revealed that the drying callus,changing the carbon source and enhancing agar density of differentiation medium and so on will also improve the conversion rate of Agrobacterium-mediated genetic transformation, then we obtain a new system .2,we found that the probability of hpt were respectively 85% and 90% and the probability of gus were respective 92% and about 96% in transgenic calli and transgenic plants through random testing.3,we found that the conversion rate is improved from 14.4% to 26.4%.by comparing the original system to the amended system.After that, We respectively transfer the same plasid to AGL1, EHA105 and LBA4404.Then,we found the highest conversion rate of Agrobacterium-mediated genetic transformation is EHA105 which reached to 25%,following is LBA4404.