苏云金芽孢杆菌杀蚊菌株的筛选及其生物学功能鉴定

Screening of Bacillus thuringiensis mosquitocidal strains and identification of their biological functions

研究筛选对骚扰阿蚊具有杀虫活性的苏云金芽孢杆菌(Bacillus thuringiensis,Bt)菌株,并鉴定这些菌株的生物学功能,丰富杀蚊菌株资源库.以145株Bt菌株为实验材料,采用生物活性测定、扫描电镜观察、产淀粉酶和产蛋白酶功能测定等方法,筛选对骚扰阿蚊3龄幼虫有毒杀活性的Bt菌株.初筛和复筛后,筛选出25株校正死亡率>60%的Bt杀蚊菌株,其中7株校正死亡率达100%.Gx0002898菌株的杀蚊活性最高,LC_(50)为4.729μg/mL.扫描电子显微镜观察发现大部分杀蚊菌株芽孢期产生大量圆形和菱形晶体.研究共筛选出24株产淀粉酶和35株产蛋白酶的菌株,其中6株既对骚扰阿蚊幼虫具高毒杀活性,又具产蛋白酶和产淀粉酶能力.研究筛选获得一些同时具有杀蚊活性及产蛋白酶和产淀粉酶可能对植物病害具有防治作用的Bt菌株,为开发新型微生物杀虫药肥提供优秀实验材料.

This study screened Bt strains with insecticidal activity against A.subalbatus and identified the biological functions of these strains to enrich the resource library of mosquito-killing strains.Using 145 Bt strains as experimental materials,methods such as bioactivity determination,scanning electron microscopy observation,and determination of amylase and protease production were employed to screen Bt strains toxic to third-instar larvae of A.subalbatus.After primary and secondary screening,25 Bt mosquito-killing strains with corrected mortality rates>60%were selected,among which 7 strains exhibited a corrected mortality rate of 100%.Strain Gx0002898 showed the highest mosquito-killing activity,with an LC_(50) of 4.729μg/mL.Additionally,scanning electron microscopy observation revealed that most mosquito-killing strains produced large quantities of circular and rhomboid crystals during the spore stage.A total of 24 strains producing amylase and 35 strains producing protease were screened,among which 6 strains showed both high toxicity to Aedes larvae and the ability to produce protease and amylase.This study identified some Bt strains with potential dual effects of mosquito-killing activity and production of protease and amylase,which may have potential for controlling plant diseases,thus providing excellent experimental materials for the development of new microbial insecticides and fertilizers.