论文部分内容阅读
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 r DNA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/m L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/m L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。
In order to isolate and identify Bacillus thuringiensis strains with high virulence to Asian corn borer, the wild strains were isolated from the soil of Jilin Academy of Agricultural Sciences by checkerboard collection method, and their morphological and biochemical characteristics were observed. Type identification and its indoor bioactivity against three Lepidopteran pests was determined. The results showed that the strain was round and dark white colonies on LB medium with irregular edges and positive Gram stains. Most of the sporulation crystals produced were irregular. The 16S r DNA sequence shared 99% homology with the Bacillus thuringiensis NBRC 13865. The strain was cry2 + cry9 genotype. The homology of the encoded amino acid sequence to Cry2Ab and Cry9Ea was 94% and 99% Bacillus thuringiensis, named JN001. The strain was highly toxic to Asian corn borer. The corrected mortality was 95.06% after inoculation of the 3rd instar larvae at a density of 1.0 × 109 cells / m L for 72 h. The LC50 was 4.12 × 103 / m L, while the toxicity to Spodoptera litura and armyworm was weak. After 72 h of inoculation, the corrected mortality rates were 12.88% and 7.34%, respectively. The results showed that this strain was a new strain of Bacillus thuringiensis which had strong virulence to Asiatic corn borer, and had a good potential for exploitation.