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- 2015
苏云金芽胞杆菌一新菌株的鉴定及其杀虫活性
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Abstract:
为分离并鉴定对亚洲玉米螟具有高毒力的苏云金芽胞杆菌菌种,通过棋盘式采集法从吉林省农业科学院试验田土壤中分离获得野生菌株,进行了形态、生化特性、伴孢晶体观察及基因型鉴定,并测定了其对3种鳞翅目害虫的室内生物活性.结果显示:该菌株在LB培养基上为圆形、暗白色菌落,边缘不整齐,革兰氏染色阳性,产生的伴孢晶体形状多为不规则形.16S rDNA序列与苏云金芽胞杆菌属的NBRC 13865同源性达99%;该菌株为cry2+cry9复合基因型,编码氨基酸序列与Cry2Ab和Cry9Ea蛋白同源性分别为94%和99%,鉴定为苏云金芽胞杆菌,命名为JN001.该菌株对亚洲玉米螟具有较高毒性,以1.0×109个/mL菌体浓度接种3龄幼虫72 h后,其校正死亡率为95.06%,致死中浓度(LC50)为4.12×103个/mL菌体,而对斜纹夜蛾和粘虫毒性较弱,接种72 h后校正死亡率分别为12.88%和7.34%.表明该菌株是1株对亚洲玉米螟具有较强毒力的苏云金芽胞杆菌新菌株,具有较好的开发利用潜力.
To isolate and identify new strains of Bacillus thuringiensis against Ostrinia fumacalis, a new wild strain was obtained from the experimental field of Jilin Academy of Agricultural Sciences by using chessboard sampling method. The bioactivity of the strain against important insects, O. fumacalis, Spodoptera litura and Mythimna separate were also tested in the laboratory. The results showed that the strain colony cultured on luria-bertani medium was circular and dark white with irregular edge. Furthermore, it was a gram-positive strain and produced irregular parasporal crystals. It was homologous to B. thuringiensis strain NBRC 13865 with 99% identity. In addition, cry2 and cry9 genes were identified from the strain, which encoded two Cry proteins sharing 94% and 99% identity with Cry2Ab and Cry9Ea, respectively. All these results indicated that the strain was a new member of B. thuringiensis, and it was designated as B. thuringiensis JN001. The strain JN001 had the highest toxicity against O. fumacalis among the three pests. The corrected mortality and LC50 against O. fumacalis were 95.06% and 4.12×103/mL when the third-instar larvae fed with media containing 1.0×109/mL of JN001 for 72 hours, respectively. However, the corrected mortality of strain JN001 against the other two kinds of pests was very low. The results indicated that the strain JN001 was a new strain of B. thuringiensis with high toxicity against O. fumacalis and was a potential strain for microbial insecticide development.
