对甘薯茎线虫具有杀虫活性的苏云金芽胞杆菌筛选及特性鉴定

Screening and Characterization of Nematicidal Bacillus thuringiensis Strains against Ditylenchus destructor

为筛选对甘薯茎线虫具有高毒力的苏云金芽胞杆菌(Bacillus thuringiensis,Bt)菌株,提取12株供试Bt菌株的晶体蛋白,溶解后加入到甘薯茎线虫悬浮液中,统计3 d和7 d后甘薯茎线虫的死亡率.经初筛和复筛后得到一株对甘薯茎线虫具有高毒力的Bt菌株YBT-008,其对甘薯茎线虫的LC50值为203.76μg/mL.研究了YBT-008的生物学特性,结果表明,YBT-008在LB培养基上培养约12 h后进入稳定期,并且伴随芽胞的形成产生卵圆形的伴胞晶体;SDS-PAGE分析表明YBT-008可产生多种待鉴定的晶体蛋白类型,质粒检测显示该菌株有5条质粒条带.YBT-008的获得为利用Bt防治甘薯茎线虫提供了新型菌株和基因资源.

The nematicidal activities of 12 Bacillus thuringiensis strains against Ditylenchus destructor were tested to obtain nematicidal B.thuringiensis strains with high toxicity to D.destructor.The insecticidal crystal proteins（ICPs） were extracted from each B.thuringiensis strain and dissolved.The larva and adult of D.destructor were incubated with ICPs,and the mortalities of D.destructor were counted after 3 and 7 days.After primary and secondary screening,one Bt strain,YBT-008,which showed high toxicity to D.destructor,was obtained.The result of bioassay indicated that the estimated LC50of YBT-008 against D.destructor was 203.76 μg/mL.The primary characterization of strain YBT-008 was also analyzed.The growth curve showed that YBT-008 was in the stationary phase after 12 h incubation.The ovate parasopral crystals could be obviously observed by microscope.The electrophoresis result indicated that plasmids from YBT-008 displayed 5 bands.The SDS-PAGE analysis showed that YBT-008 produced a variety of unidentified proteins.The finding of YBT-008 strain would provide new strain and gene resources for the biological control against D.destructor.