Development of lepidopteran pest-resistant transgenic japonica rice harboring a synthetic cry2A* gene

A synthetic cry2A* gene encoding Bacillus thuringiensis (Bt) δ-endotoxin that resistance to lepidopteran pest was transformed into japonica rice variety Jijing 88, which is the most widely cultivated variety in Jilin Province, Northeast China, by Agrobacterium-mediated transformation. A total of 106 independent transformants overexpressing cry2A* gene driven by ubiquitin (Ubi) promoter was produced. Three single-copy homozygous transgenic lines were finally selected based on the results of PCR analysis, segregation ratio of Basta resistance, and Southern hybridization analyses. RT-PCR and enzyme linked immune sorbent assay (ELISA) revealed that cry2A* transcripts and protein were highly expressed in these lines. The high level of Cry2A* protein expression resulted in high resistance to rice striped stem borer as evidenced by insect feeding bioassays. Our results demonstrate that cry2A* transgenic japonica rice confers resistance to the rice striped stem borer in the laboratory conditions.