Identification and pathogenicity of bacterial strains carried by American pine wood nematodes

Abstract

To confirm that pine wood nematodes carrying attenuated bacterial strains could alleviate pine wilt disease，bacteria were isolated from two nematodes native to America. Bacterial virulence and pathogenicity were tested with pine seedlings，and preliminary identification of predominant strains was determined using bacterial staining reactions and morphology combined with 16S rDNA sequence analysis. Results of the isolation experiment showed that the predominant bacteria which American nematodes carried were strains MG4 （Delftia tsuruhatensis），MG5 （Pseudomonas putida），MG8 （Stenotrophomonas maltophilia），and MG9 （Pantoea sp.） Virulence and pathogenicity results demonstrated that compared with the high virulent bacteria strains（Pseudomonas fluorescence） isolated from Chinese nematodes，toxicity and pathogenicity of bacterial strains from America were relatively low. Thus，the bacteria carried by American nematodes should be considered the candidates for biological control agents.［Ch，2 fig. 3 tab. 20 ref.］