[Observation by transmission electron microscope and identification of endophytic bacteria isolated from Bursaphelenchus xylophilus and B. mucronatus].

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.