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Functional identification of the gene bace16 from nematophagous bacterium Bacillus nematocida

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Bacillus nematocida is a Gram-positive bacterium capable of killing nematodes. Our recent studies identified an extracellular serine protease Bace16 in B. nematocida as a candidate of pathogenic factor in the infection against nematodes, which displayed a high similarity with the serine protease family subtilisin BPN’, and the MEROPS ID is S08.034. To further confirm the roles that bace16 played in the mechanism of nematocidal pathogenesis, recombinant mature Bace16 (rm-Bace16) was expressed in Escherichia coli strain BL21 using pET-30 vector system. Bioassay experiments demonstrated that the purified recombinant protease had the ability to degrade nematode cuticles and kill nematodes. In addition, a bace16 knockout mutant of B. nematocida constructed by homologous recombination showed considerably lower proteolytic activity and less than 50% nematocidal activity than the wild-type strain. These results confirmed that Bace16 could serve as an important virulence factor during the infectious process.

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We are grateful to Ms. W. Zhou for her invaluable help in facilitating the work. In addition, we thank Dr. Jianping Xu, the associate professor from McMaster University in Canada, for the invaluable comments and revisions. The work was funded by the projects from National Natural Science Foundation Program of People’s Republic of China (30500338, 30630003), Department of Science and Technology of Yunnan Province, People’s Republic of China (nos. 2005NG05, 2004C0004Q and 2004C0001Z).

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Correspondence to Keqin Zhang.

Additional information

Qiuhong Niu and Xiaowei Huang contributed equally to this work.

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Niu, Q., Huang, X., Zhang, L. et al. Functional identification of the gene bace16 from nematophagous bacterium Bacillus nematocida . Appl Microbiol Biotechnol 75, 141–148 (2007). https://doi.org/10.1007/s00253-006-0794-7

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  • Knockout Mutant
  • Nematophagous Fungus
  • Nematicidal Activity
  • Paecilomyces Lilacinus
  • Insoluble Inclusion Body