Production of transgenic rice new germplasm with strong resistance against two isolations of Rice stripe virus by RNA interference.

Rice stripe disease, with the pathogen Rice stripe virus (RSV), is one of the most widespread and severe virus diseases. Cultivating a resistant breed is an essential and efficient method in preventing rice stripe disease. Following RNA interference (RNAi) theory, we constructed three RNAi binary vectors based on coat protein (CP), special-disease protein (SP) and chimeric CP/SP gene sequence. Transgenic lines of rice cv. Yujing6 were generated through Agrobacterium-mediated transformation. We inoculated T1 generation plants from each line derived from CP/SP, CP, and SP transgenic rice plants with two RSV isolates from Shandong Province and Jiangsu Province using viruliferous vector insects. In these resistance assays, chimeric CP/SP RNAi lines showed stronger resistance against two isolates than CP or SP single RNAi lines. Stable integration and expression of RNAi transgenes were confirmed by Southern and northern blot analysis of independent transgenic lines. In the resistant transgenic lines, lower levels of transgene transcripts and specific short interference RNAs were observed relative to the susceptible transgenic plant, which showed that virus resistance was increased by RNAi. Genetic analysis demonstrated that transgene and virus resistance was stably inherited in the T2 progeny plants.