Stable inheritance of RF2a transgene integration in transgenic IR64 rice plants and evaluation of their tolerance against Rice tungro virus

Abstract

Rice tungro disease (RTD) is one of the devastating diseases in Asia, caused by simultaneous infection of Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). The spread of these viruses is difficult to control especially in areas with intensive rice planting. RF2a is a rice transcription vector, regulate the expression of RTBV promoter and is also important for rice development. The overexpression of RF2a in transgenic rice plants has been reported can reduce virus accumulation and leads to tolerance against tungro virus. Transformation of RF2a transgene into a commercial susceptible cultivar, IR64 had been conducted. Four trangenic rice lines at T1 and T2 generations have been obtained. Stable inheritance and expression of RF2a transgene in successive generations are an indication of the successful development of tungro-tolerant cultivars. Therefore, PCR analysis for RF2a transgene and bioassay on transgenic plants at T2 and T3 generations against tungro virus had been done. PCR analysis showed that the RF2a transgene which is indicated by the presence of hpt was stably inherited and several transgenic rice plants harboring the overexpressed RF2a are gaining tolerance to an Indonesian tungro Purwakarta isolate compared to the IR64 wild type under greenhouse conditions.