Bt新菌株资源的采集与鉴定

【目的】寻找对致倦库蚊高效的苏云金芽胞杆菌(Bacillus thuringiensis,Bt)杀蚊菌株新资源。【方法】从福建省的武夷山自然保护区、建阳、建瓯、浦城等多个地区采集土壤样品,采用热处理法从土壤中分离Bt菌株,并测定其对致倦库蚊活性的效果。【结果】从125份土壤样品中分离出71株Bt菌株,经生物测定得到4株对致倦库蚊有效菌株(QQ13、QQ42、QQ66和QQ92)。其中,QQ66和QQ92有较高的毒性,均有几丁质酶基因,没有检测到cry1、cry1Ⅰ、cry2、cry4、cry5、cry6、cry7、cry8、cry9、cry10和cry11基因,在75～100 ku处各有一条杀虫晶体蛋白条带。【结论】采集和鉴定到的Bt新菌株资源将对致倦库蚊的生物防治起到促进作用。

Isolation and identification of new strains of the entomopathogen Bacillus thuringiensis

Aim] To isolate and identify effective strains of Bacillus thuringiensis (Bt) that can kill the mosquito Culex quinquefasciatus.Method] Soil samples were collected from several areas in Fujian Province, including Wuyi Mountain, Jianyang, Jian''ou and Pucheng. Bt strains were isolated from the soils by heat treatment and their activities against C. quinquefasciatus was determined.Result] 71 Bt strains were isolated from 125 soil samples and subjected to bioassay. Four strains were active against C. quinquefasciatus (QQ13, QQ42, QQ66 and QQ92). Among them, QQ66 and QQ92 had the highest toxicities and harbored chitinase genes. Although cry1, cry1I, cry2, cry4, cry5, cry6, cry7, cry8, cry9, cry10 and cry11 were not detected in the two strains, they had an insecticidal crystal protein with a molecular weight of 75-100 ku.Conclusion] The identified Bt new strains may promote the biological control of C. quinquefasciatus.