Based on the observation that ray parenchyma cell death took place prior to nematode population increase in pine wood,the authors suspected that any microorganisms carried by pathogenic nematodes would be involvedin the pathogenic process.The authors screened pathogenic nematode-accompanying microbes for their toxicity against cultured cells of Pinus thunbergiis and isolated and identified 3 toxic strains,Bacillus cereus HY-3,B.subtilis HY-16,and Bmegaterium HY-17 , whose toxic products were identified as phenylacertic acid.Inoculation of pine seedlings with the toxic bacterium alone did not cause the seedling to wilt , but inoculation of pine seedlings with the toxic bacterium carried by weakly pathogenic nematodes wilted the seedling as much as strongly pathogenic nematodes . These results suggested that phenyllacetic acid-producing bacteria could invade pine trees by accompanying pine wood nematodes , and produce phenylacetic acid , a toxic metabolite , in the wood.
phenylacetic acid producer
fluorescence microscopic analysis
pine wilt disease