思茅松毛虫7龄幼虫肠道好氧细菌的筛选及毒力测定

Screening and virulence of intestinal aerobic bacteria from the 7th instar larvae of Dendrolimus kikuchii

将思茅松毛虫7龄幼虫中肠样品倍比稀释后涂布平板分离菌株,共分离得到14株好氧细菌。以细菌基因组DNA为模板,用细菌16S rDNA通用引物(27f,1492r)对模板扩增,并用2种限制性内切酶HaeⅢ和HindⅢ对PCR扩增产物进行ARDRA多态性分析。对聚类图谱的分析结果发现,14株好氧细菌在86%的相似水平上聚成4个不同分类操作单元(OTU),表明思茅松毛虫7龄幼虫肠道内好氧细菌的遗传多样性水平偏低。室内毒力试验表明,肠道细菌杀虫死亡高峰期在4～8 d,菌株7I-5杀虫效果最佳,12 d时校正死亡率达到64.29%。

Fourteen aerobic bacteria in Dendrolimu. kikuchii intestine were isolated with plating method. The bacterial genomic DNA were used as templates. A way of genetic diversity analysis of intestinal aerobic bacteria was established, using PCR technique （premier27f, 1492r） and ARDRA patterns which used enzyme digestion（Haelll and HindlU ） of cloned 16S rDNA gene sequences. The results showed that 14 strains could be divided into 4 operational taxonomic unit（OTU） on 86% similarity level. The result proved that the intestinal aerobic bacteria genetic diversity in Dendrolimu. kikuchii was low. The toxicity test in laboratory showed that the peak mortality of Dendrolimu kikuchii was 4 and 8 days after spraying with intestinal aerobic bacteria insecticides, and strain 4 had the best effectiveness which showed 64. 29% corrected mortality 12 days after the spraying.