苏云金芽胞杆菌的鉴定及对椰子织蛾的致死作用

Identification of Bacillus thuringiensis and insect activity against Opisina arenosella Walker

【背景】利用采集到的样品分离出苏云金芽胞杆菌菌株,针对椰子织蛾幼虫进行室内生物活性测定,以期获得对椰子织蛾幼虫具有高毒力菌株,并为椰子织蛾的生物防控提供理论和技术依据,同时为转Bt基因作物提供新的基因资源。【方法】在海南岛椰子织蛾潜在分布区采集样品,利用温度法筛选苏云金芽胞杆菌并进行形态学和分子生物学鉴定,采用浸叶法进行Bt菌株对椰子织蛾幼虫的生物活性测定。【结果】海南省保亭县土壤样品中筛选出8株菌株,电子显微镜下观察到该批菌株含有菱形、球形、方形晶体;通过分子生物学鉴定明确了6株菌株含有cry基因,2株没有鉴定出cry基因;利用相同浓度菌悬液对椰子织蛾幼虫进行了生物活性测定,结果表明,50μg·m L-1的BAT10菌株杀虫晶体蛋白对椰子织蛾幼虫的致死率达100%,同样浓度的29-15-4与BAT20菌株杀虫晶体蛋白对椰子织蛾幼虫的致死率超过80%,其余5株Bt的杀虫晶体蛋白致死率较低,致死率小于50%。【结论与意义】本试验筛选出1株高毒力菌株和2株效果较好的Bt菌株,可应用于椰子织蛾的生物防控。

【Background】The biological activity of Bacillus thuringiensis（ Bt） strains collected from soil samples was tested against Opisina arenosella Walker,in order to obtain high insect activity strains that may help control the species. The second objective of this study was to provide new genetic resources for transgenic plant of Bt that could be more resistant to this species. 【Method】Soil samples were collected from different areas of Hainan Province potentially suitable for O. arenosella. The temperature screening method was used to isolate Bt strains,which were then identified based on their morphology and molecular biology. The toxicity of Bt strains to larvae of O. arenosella was tested by leaf immersion bioassay method. 【Result】Eight Bt isolates were obtained from Baoting soil samples,Hainan Province. The 8 Bt isolates included bipyramidal crystal,spherical crystal,square crystal types. PCRRFLP analysis showed that Cry1,cry1 I and cry2 type genes were present in these isolates,but the cry gene-types of two isolates were unknown. The toxicity of the extracted insecticidal crystal proteins（ ICP） of the 8 strains against larvae of O. arenosella was assayed. The results indicated that the use of ICP of BAT10（ 50 μg·m L-1） resulted in 100% mortality of the larvae. ICP of 29-15-4 and BAT20 resulted in more than 80% mortality while the ICP of the other five strains showed less than 50% mortality. 【Conclusion and significance】This study showed that effective Bt strains could be found in soil potentially suitable to O. arenosella and among them,two strains had the potential to be used as biological control against this species.