| 郭 鹬，任广豪，刘金源，钟子雯，樊江斌，于 欢,,一株对草地贪夜蛾具有胃毒活性的克雷伯氏菌分离及全基因组分析[J].环境昆虫学报,(): |
| 一株对草地贪夜蛾具有胃毒活性的克雷伯氏菌分离及全基因组分析 |
| Isolation and whole genome analysis of a strain of Klebsiella bacterium with gastrotoxic activity against Spodoptera frugiperda (Lepidoptera: Noctuidae) |
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| 中文关键词: 昆虫肠道分离细菌 草地贪夜蛾 杀虫活性检测 克雷伯氏菌 细菌全基因组分析 |
| 英文关键词:Insect gut isolated bacteria Spodoptera frugiperda insecticidal activity bioassay Klebsiella pneumoniae bacterial genomic DNA analysis |
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| 中文摘要: |
| 本研究从田间采集的菜青虫Pieris rapae L.中肠分离获得可培养的、菌落形态有显著差异的细菌菌落53个。将这些菌落接种至新鲜的LB培养基中培养3 d后，用于浸泡人工饲料并饲喂草地贪夜蛾Spodoptera frugiperda Smith 2龄幼虫，其中9株对草地贪夜蛾幼虫展现出一定的胃毒活性。针对杀虫活性最高的一株——克雷伯氏菌Klebsiella pneumoniae A7株进行了进一步的检测，发现其在培养后1 d、2 d和3 d后对草地贪夜蛾2龄幼虫处理96 h的致死率分别为26.39% ± 11.98%、8.33% ± 3.73%、和56.25% ± 10.26%，均显著高于对照组试虫的死亡率（P<0.05）。全基因组测序的结果表明，A7基因组总长度为8.55 Mb，GC含量51.78%，可编码8 148个基因，另含有3大小分别为190 495 bp、89 806 bp和77 436 bp的质粒。进一步的分析结果表明，A7株编码的748种基因中，有214种毒力基因的检出率在70%以上，306种毒力基因的检出率低于50%，其余228种毒力基因的检出率在50%~70%之间；进一步利用VFDB数据库对214种毒力基因检出率在70%以上的基因进行注释，分别注释到13类毒力相关基因。可以观察到A7在16S rDNA系统发育树上与其他克雷伯氏菌属Klebsiella sp.的亲缘关系。本研究报道了一种对草地贪夜蛾幼虫具有杀虫活性的克雷伯氏菌，结合基因组学的分析，为草地贪夜蛾的生物防治奠定了基础。 |
| 英文摘要: |
| Fifty-three cultivable bacterial colonies with significant differences in colony morphology were isolated from the midguts field collected Pieris rapae L. in this study. After being cultured in fresh liquid LB medium for 3 days, the artificial diet dots smeared with these bacterial-containing LB medium were fed to 2nd instar Spodoptera frugiperda Smith larvae, 9 of the isolated bacterial colonies showed insecticidal activity. Further bioassays were conducted on the Klebsiella pneumoniae A7 strain, which had the highest insecticidal activity among all the tested bacterial strains. The mortality of 2nd instar S. frugiperda was 26.39 ± 11.98%, 8.33 ± 3.73%, and 56.25 ± 10.26% with the serve of A7 cultured for 1, 2, and 3 days, respectively, which were significantly higher than those of the control group (P<0.05). The results of whole genome sequencing showed that the total length of the A7 genome was 8.55 Mb, with a GC content of 51.78%, which could encode 8148 genes. A7 contains three plasmids with the sizes of 190 495 bp, 89 806 bp, and 77 436 bp, respectively. Further analysis results showed that among the 748 genes encoded by A7 strain, the detection rate of 214 virulence genes was over 70%, the detection rate of 306 virulence genes was below 50%, and the detection rate of the remaining 228 virulence genes was between 50~70%. With the detection of VFDB database, 214 virulence related genes that had detected rate of virulence genes over 70% were annotated into 13 categories.This study reports a K. pneumoniae bacterium with insecticidal activity against the S. frugiperda larvae. Combined with genomic analysis, it lays the foundation for the biological control of S. frugiperda. |
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