中文摘要：

为探讨二化螟Chilo suppressalis （Walker）肠道微生物多样性与抗药性的关系， 本研究采用基于16S rDNA 的变性梯度凝胶电泳（DGGE）和16S rDNA文库序列分析方法, 检测和分析了二化螟4个抗药性水平不同的种群幼虫中肠细菌群落多样性。生测结果表明， 以二化螟黑龙江种群（HLJ种群）作为相对敏感品系， 连云港种群（LYG种群）对杀虫单、 毒死蜱、 三唑磷的抗性为低抗至中抗水平， 瑞安种群（RA种群）和诸暨种群（ZJ种群）的抗性为中抗至极高抗水平， 这3个种群对阿维菌素均为敏感水平。16S rDNA文库序列分析表明， PCR 扩增得到的16S rDNA基因代表了二化螟幼虫中肠内21种细菌系统发育型， 其中大多数属于链球菌属Streptococcus。在不同抗药性水平二化螟种群中， 幼虫中肠微生物群落除ZJ种群的Lactococcus garvieae， L. lactissubsplactis和Ochrobactrum anthropic等3种菌较丰富外， 其余均以肠球菌属Enterococcus为主。DGGE 图谱显示， HLJ种群条带较为单一， LYG种群条带最为丰富， ZJ种群与RA种群条带丰富度相似。4个种群均出现Enterococcus faecium， E. hirae. 和Arthrobacter sp.等细菌， 且以肠球菌属Enterococcus为主。结果显示了不同抗药性水平的二化螟种群中肠细菌群落的丰富度存在差异， 推测可能与二化螟不同抗药性差异有关。

英文摘要：

Bacterial community in midguts of larvae of four populations of the striped stem borer, Chilo suppressalis, with different levels of resistance to insecticides was detected and analyzed using PCR-DGGE and 16S rDNA libraries. The bioassay showed that compared to the susceptible strain, the Heilongjiang population （HLJ population）, the Lianyungang population （LYG population） had low to middle resistance level to monosultap, chlorpyrifos and triazophos, the Rui’an population （RA population） and Zhuji population （ZJ population） had middle to very high resistance level to the above three insecticides, and the latter three populations all were susceptible to avermectins. DNA sequence analysis indicated that the PCR-amplified 16S rDNA genes represented 21 bacteria phylotypes, and most of them belonged to the genus Streptococcus. Bacterial community in larval midgut of four different resistant populations was mainly the genus Enterococcus, except that the dominant bacteria in ZJ population were Lactococcus garvieae, L. lactissubsplactis and Ochrobactrum anthropic. The DGGE profiles demonstrated that the bands of HLJ population were simple, those of LYG population were the most abundant, and the band richness of ZJ population was similar to that of RA population. The common bacteria in the four populations were Enterococcus faecium, E. hirae and Arthrobacter sp., and the main bacteria were the genus Enterococcus. The results suggest that there is difference in bacterial abundance in larval midgut of C. suppressalis with different levels of resistance to insecticides, which may be related to the difference of resistance to insecticides among different populations of C. suppressalis.