对棉铃虫高效的2个Bt新菌株及其特性的研究

The Study of Two Highly Toxic Bacillus thuringiensis Strains to Heliothis armigera and their Character

本文对从浙江省土壤中分离并经初筛的2个苏云金芽孢杆菌（Bacillusthuringiensis．Bt）菌株进行了生物测定、晶体特性及生化特征的研究。生测结果表明，2个Bt菌株对棉铃虫具有很高的毒效，48h的校正死亡率高达96％～98％，LD50（半致死剂量）范围约为6.0～7.0μg晶体蛋白。扫描电镜观察表明，2个菌株均有菱形和方形2种伴孢晶体。SDS-PAGE图谱显示它们均有135KDa和65KDa2条主带。生化测定结果推断9508和9511菌株分属于Kur和Thu生化亚种。

In this paper, the toxicities, the crystal character and biochemical character of two Bacillus thuringiensis strains isolated from soil in zhejiang province were studied. Bioassay results showed that the two Bt strains possessed very high toxicity to Heliothis armigera. The corrected mortality reached 96%~ 98% within 48 hours. The LD50 was about 6.0~ 7.0 μg crystal protein. The scanning electro-microscope (SEM) showed that the two strains had both rhomboid and cuboidal crystals. The pattern of SDS-PAGE indicated that the two strains had 135KDa and 65KDa main bands. Biochemical-assay results infered that 9508 and 9511 strains belonged to Kur and Thu biochemical types respectively.