Bacillus sp. B16 kills nematodes with a serine protease identified as a pathogenic factor.

摘要: An endospore-forming bacterium, strain B16, was isolated from a soil sample and identified as Bacillus sp. The presented remarkable nematotoxic activity against nematode Panagrellus redivivus. crude extracellular protein extract culture supernatant of the bacteria killed about 80% tested nematodes within 24 h, suggesting involvement proteases. A homogeneous protease purified by chromatography, hypothesis proteinaceous pathogeny in infection B16 confirmed experiments killing living degradation cuticle when treated with homogenous protease. gene for virulence cloned, nucleotide sequence determined. deduced amino acid showed significant similarity subtilisin BPN' but low homology other cuticle-degrading proteases previously reported fungi. Characterization revealed molecular mass 28 kDa optimum at pH 10, 50°C. can hydrolyze several native substrates, including collagen cuticle. To our knowledge, this is first report serine genus that serves pathogenic factor nematodes, an important step understanding relationship between bacterial pathogen host improving nematocidal biological control.