| Southern rice black-streaked dwarf disease which caused by Southern rice black-streaked dwarf virus (SRBSDV) is spreading among China, and it caused serious negative effects on rice production in China. To find the genomic functions of SRBSDV and obtain resistant rice, we analyzed the potential target sequences of S7-1of SRBSDV, and created RNA interference (RNAi) constructs targeting P7-1gene sequence of virus. The constructs were transformed into japonica cv. Nipponbare via Agrobacterium tumefaciens. Transgenic To rice plants were obtained. Among these transgenic plants,45positive of lines were selected by PCR analysis, and6single-copy lines were identified by Southern blotting analysis.When the transgenic T1rice plants and control rice plants were inoculated with the viruliferous insect vector white-backed planthoppers(WBPHs) at three-leaf stage, we found that transgenic lines developed severe symptoms, indicating that the transgenic rice plants did not have the resistance to SRBSDV. However, when transgenic T1rice plants were inoculated with a population of non-viruliferous WBPHs for3days and then exposed to diseased rice plants, immunofluoresecence microscopy studies showed that the spread of SRBSDV had been strongly inhibited in the body of WBPHs which pre-treated with transgentic rice plants. The control group with viruliferous WBPH rate was as high as80%, while the rate of treated group was around30%, Furthermore, RT-PCR assay indicated that viral replication of SRBSDV was significantly inhibited in WBPHs which pre-treated with transgentic rice plants,showing that P7-1was definitely necessary for the spread of SRBSDV in the body of WBPHs.In conclusion, our results showed that P7-1was not essential for the infection of SRBSDV in rice plants, but it was required for viral infection in its insect vector WBPH. The RNAi constructs expressed in rice can efficiently trigger gene silencing in WBPH, and the viral replication of SRBSDV was significantly inhibited. |
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