Cloning and characterization of a novel gene cry9Ea7 encoding crystal protein with high toxicity against Trichoplusia ni

Abstract:

Abstract: [Objective] We cloned a novel cry9Ea gene encoding a Cry9Ea protein with a high insecticidal activity against Trichoplusia ni. [Methods] We identified a cry9-type gene from Bt strain (Bt4) by PCR-RFLP. The full length cry9Ea gene was amplified by PCR with a pair of primers F9EA/R9EA. [Results] We cloned the complete cry9Ea7 gene into pET21b. The SDS-PAGE results showed that the 130 kDa Cry9Ea7 protein was expressed in E. coli BL21(DE3). We also constructed an engineering strain BioHD9Ea7 by transforming a shuttle vector pSXY422b containing the cry9Ea7 gene into Bt acrystalliferous mutant HD73-(cry-). The bioassay results indicated that the Cry9Ea7 protein was highly toxic against Trichoplusia ni neonates, and the LC50 value was 0.044 μg/mL. However, the Cry9Ea7 protein showed no activity against Spodoptera exigua and Helicoverpa armigera neonates. [Conclusion] The novel cry9Ea7 gene encoding Cry9Ea7 is highly toxic against Trichoplusia ni neonates.