Resistance Mechanism Of Major Commercial Rice Varieties To RSV And Construction Of Trangenic Rice To Fight Against Virus

Rice stripe disease caused by Rice stripe virus (RSV) is one of the important virus diseases of rice, which transmitted by small brown planthopper (Aodelphax striatellus Fallen, SBPH). It distributed in 16 provinces in China. In recent years, it has occurred seriously in the eastern China, especially in the major commercial japonica rice area--Jiangsu Province. There is 42 counties in the Jiangsu Province has occurred such disease since a large outbreak of rice stripe virus in 2004, and the affected area had reached 2,320, 000 acreages. So applying resistant variety is the most cost-effective measures to prevent and control this disease.The objective of this research was to analysis the resistance mechanism of major commercial rice and create the transgenic rice with mammalian 2'5'oligoadenylate system to fight against the virus disease. To make it clear of the resistance mechanism of 8 major commercial japonica rice varieties, the methods of inoculation at seedling stage, non-preference test and antibiosis test were taken to analyze the resistance to rice stripe virus (RSV) and the vector, small brown planthopper. The another work was to obtain the transgenic rice with mammalian 2'5'oligoadenylate system and analysis the resistance of transgenic rice to RSV and Rice black streaked dwarf (RBSDV). The main results obtained were showed as follows:1. The resistance to RSV and vector SBPH was not consistent among the eight rice varieties-Xudao No.3,Xudao No.4,Yandao No.8,Zhendao 88,Ningjing No.3,Zhendao 99,Lianjing No.4 and Zhendao No.8. The analyses of resistance of rice varieties to RSV indicated that all the rice cultivars selected in this study were resistant to RSV. However, the resistance to SBPH suggested that the rice varieties of Zhendao 88 and Zhendao 99 were weakly resistant to SBPH, while the others were inclined to be infected by SBPH. Therefore, the rice stripe disease resistance of the varieties mainly derived from the resistance to the virus.2. The 2'5'oligoadenylate system (2-5A system) gene were cloned into the vector pAMM2106 and pAMM2109, respectively, and introduced into Yanjing 21, mediated by Agrobacterium-mediated transformation. As for transgenic rice with 2-5A gene and RNase L gene, we obtained a NO.4 line in T3 generation by PCR selection using two pairs of specific primers, even its T4 generation 4-1,4-2,4-3,4-4,4-5,4-6,4-7 and 4-8 are PCR double positive. In the detection of transgenic rice with 2-5A gene and RNase L gene, Southern blot analysis proved RNase L gene is integrated in T4 generation, RT-PCR results showed that the two genes are transcribed. Meanwhile, the method of inoculation at seedling stage was taken to analyze the transgenic rice resistance to RSV and rice black streaked dwarf virus (RBSDV), it turned out transgenic lines exhibited better resistance to RSV and RBSDV than the receptor cultivar Yanjing 21, eight strains enhance 15.31%～34.66% to RSV, four strain enhance 9.4%～23.53% to RBSDV.