Archives of Microbiology

, Volume 186, Issue 4, pp 297–305

Cloning, expression and deletion of the cuticle-degrading protease BLG4 from nematophagous bacterium Brevibacillus laterosporus G4

  • Baoyu Tian
  • Ning Li
  • Lihui Lian
  • Junwei Liu
  • Jinkui Yang
  • Ke-Qin Zhang
Original Paper

DOI: 10.1007/s00203-006-0145-1

Cite this article as:
Tian, B., Li, N., Lian, L. et al. Arch Microbiol (2006) 186: 297. doi:10.1007/s00203-006-0145-1

Abstract

Brevibacillus laterosporus G4, which was isolated from soil sample, kills free-living nematodes (Panagrellus redivius) and plant-parasite nematodes (Bursaphelenchus xylophilus) and degrades their cuticle in previous bioassay. Our works for B. laterosporus G4 had demonstrated that an extracellular alkaline protease BLG4 played a key role as a pathogenic factor in infection against nematode. In this study, the nematicidal activity of BLG4 was further verified by an in vitro assay with purified recombinant BLG4. The encoding gene of BLG4 was cloned and showed high degree of homology with the subtilisin subclass of serine protease gene and another reported cuticle-degrading protease gene from nematophagous bacterium Bacillus sp. B16. Deletion of BLG4 by homologous recombinant had a significant effect on the pathogenicity of B. laterosporus. In infection assays the BLG4-deficient strain (BLG4-6) lost about 50% of its nematocidal activity and in toxicity tests the mortality rate of nematodes decreased with ∼56% in comparison to wild-type strain. This is the first report analyzing the function of a subtilisin enzyme involved in bacterium against nematode at the molecular level, and it is possible to use B. laterosporus as a model to study host-parasite interaction and to gain detailed knowledge of the infection process.

Keywords

Pathogenic subtilisin Host-parasite interaction Gene deletion Heterologous expression 

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Baoyu Tian
    • 1
  • Ning Li
    • 1
  • Lihui Lian
    • 1
  • Junwei Liu
    • 1
  • Jinkui Yang
    • 1
  • Ke-Qin Zhang
    • 1
  1. 1.Laboratory for Conservation and Utilization of BioresourcesYunnan UniversityYunnanPeople’s Republic of China

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