中文摘要：

【目的】松材线虫是松树萎蔫病的病原,拟松材线虫在形态等方面与松材线虫极其相似。关于两种线虫与细菌的研究多集中于体表伴生细菌。本文要揭示松材线虫和拟松材线虫体内是否存在细菌。【方法】对松材线虫和拟松材线虫进行透射电镜观察;并采用1%升汞和抗菌素混合液对两种线虫虫体进行体表消毒后研磨,制备悬浮液涂布NA平板;通过生理生化测定和16S rDNA序列分析鉴定细菌种类。【结果】松材线虫和拟松材线虫透射电镜照片显示在两种线虫肠道内均发现细菌;体表无菌的松材线虫和拟松材线虫共分离到3株体内细菌;这3株细菌分别属于寡养单胞菌属（Stenotrophomonas）和爱文氏菌属（Ewingella）。【结论】松材线虫和拟松材线虫体内均存在细菌;这些细菌对这两种线虫可能具有一定的生理生态作用。本文是松材线虫和拟松材线虫体内存在细菌的首次报导。

英文摘要：

[Objective] The pine wood nematode,Bursaphlenchus xylophilus,morphologically similar to B.mucronatus,is the pathogen of pine wilt disease.This study was focused on the endophytic bacteria present in these nematodes.[Methods] Detailed observations were made on sections of all parts of the two types of nematodes by transmission electron microscope.The nematodes were surface-sterilized by soaking in 1% mercuric chloride and antibiotic mixture,and then ground and cultured on nutrient agar plate.The physiological and biochemical characteristics combined with molecular characterization of bacteria were analyzed and identified.[Results] Endophytic bacteria were found in intestines of the two nematodes by transmission electron microscope observations.On the basis of surface sterilization,total three bacteria strains were obtained from B.xylophilus and B.mucronatus.These bacteria belong to Stenotrophomonas and Ewingella.[Conclusion] It confirms the presence of endophytic bacteria in Bursaphelenchus xylophilus and B.mucronatus and these bacteria may play a physical and ecological roles in nematodes.