One hundred and forty - four soil samples were collected from coconut crove of seaside, Hainan Province, and 10 Bacillus thuringiensis isolates were obtained. We found there were long bipyramidal crystal, short bipyramidal crystal, square crystal types in the 10 Bt isolates. Comparison of plasmid DNA patterns by agarose gels electrophoresis was used to discriminate the types of the isolates, and the diversity of these isolates was prominent, cryl, cryll and cry2 type genes were found in these isolates by PCR-RFLP method, but the cry genetypes of three isolates BH10, BH17, and BH21 were not known. SDS-PAGE results showed that the 10 wild isolates could express Cry proteins with 130 kD molecular mass, and 2 isolates could express both 130 kD and 60 . kD protein. Bioassay results of 10 isolates indicated that six of them were toxic to Brontispa longissina.%以海南省文昌市的滨海椰林为试点,采集144份天然土壤样品,分离出10株苏云金芽孢杆菌,对其中10株菌株进行光学显微镜观察,发现菌体有长菱形、短菱形、方形等晶体类型.对这10株菌进行cry1、cry11、cry2、cry3、cry4、cry5、cry6、cry7、cry8、cry9、cry10类基因的PCR-RFLP鉴定,在7株菌中分别发现含有cry1、cry11、cry2等基因类型,而BH10、BH17、BH21菌株中不含有已知基因.SDS-PAGE分析10株野生菌株的杀虫晶体蛋白表达谱,发现表达130、60 ku这2种分子量的蛋白.利用浸叶法对椰心叶甲进行杀虫活性测定,发现6株对椰心叶甲校正死亡率高于60％的Bt菌株.
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