椰子织蛾幼虫致病Bt菌的鉴定与杀虫活性测定

从海南省五指山采集的椰子织蛾僵虫上分离得到一株对椰子织蛾幼虫具有毒杀作用的菌株WZS171并对其生物防治潜力进行评测。通过形态学、cry基因的鉴定明确了该菌株为苏云金芽胞杆菌(Bt)。基因鉴定结果表明该菌株含有cry1Aa13、cry1Gb1、cry1D、cry1Ia、cry2Af共5种新型cry基因,NCBI Blast与GenBank中已知基因序列最大相似性分别为98%、99%、90%、92%、99%;生测结果表明72 h后该菌株菌悬液对椰子织蛾幼虫的LC₅₀为9.08 μg/mL,95%置信区间6.72~12.26 μg/mL。该菌株含有5种新型的杀虫编码基因,并且对椰子织蛾幼虫具有较高毒力,生物防治潜力大。

Identification of Bacillus thuringiensis from Opisina arenosella and Determination of Its Insecticidal Bioactivity

A virulent strain WZS171 with high infectivity was isolated from naturally infected and dead larvae of Opisina arenosella Walker collected from Hainan Wuzhishan. The strain was evaluated for its insecticidal bioactivities. The strain was identified as Bacillus thuringiensis by morphological tests and analysis of cry genes. The new genes of cry1Aa13, cry1Gb1, cry1D, cry1Ia, cry2Af were found in this isolate. NCBI BLAST revealed that the nucleotide fragments of these genes showed homology of 98%, 99%, 90%, 92% and 99%, respectively, with the known genes at the GeneBank. Bioactivity of WZS171 against the larvae of Opisina arenosella Walker was assayed in laboratory. WZS171 showed high insecticidal activity at 72 h post-treatment, with a LC₅₀ of 9.08 μg/mL and a confidence interval of 6.72-12.26 μg/mL at the 95% confidence level. These results show that WZS171 is host specific in virulence and highly virulent against larvae of Opisina arenosella Walker.