Transgenic japonica rice expressing the cry1C gene is resistant to striped stem borers in Northeast China

Rice production and quality are seriously affected by the lepidopteran pest, striped stem borer (SSB), in Northeast China. In this study, a synthetic cry1C gene encoding Bacillus thuringiensis (Bt) delta-endotoxin, which is toxic to lepidopteran pest, was transformed into a japonica rice variety (Jigeng 88) in Northeast China by Agrobacterium-mediated transformation. Through molecular detection and the Basta resistance germination assay, a total of 16 single-copy homozygous transgenic lines were obtained from 126 independent transformants expressing cry1C. Finally, four cry1C-transgenic lines (JL16, JL23, JL41, and JL42) were selected by evaluation of the Cry1C protein level, insect-resistance and agronomic traits. The cry1C-transgenic lines had higher resistance to SSB and higher yield compared with non-transgenic (NT) control plants. T-DNA flanking sequence analysis of the transgenic line JL42 showed that the cry1C gene was inserted into the intergenic region of chromosome 11, indicating that its insertion may not interfere with the genes near insertion site. In summary, this study developed four cry1C-transgenic japonica rice lines with high insect resistance and high yield. They can be used as insect-resistant germplasm materials to overcome the problem of rice yield reduction caused by SSB and reduce the use of pesticides in Northeast China.