title: Bacilysin from Bacillus amyloliquefaciens FZB42 has specific bactericidal activity against harmful algal bloom species.
abstract: Harmful algal blooms, caused by massive and exceptional overgrowth of microalgae and cyanobacteria, are a serious environmental problem worldwide : In the present study, we looked for Bacillus strains with sufficiently strong anticyanobacterial activity to be used as biocontrol agents. Among 24 strains, Bacillus amyloliquefaciens FZB42 showed the strongest bactericidal activity against Microcystis aeruginosa, with a kill rate of 98.78%. The synthesis of the anticyanobacterial substance did not depend on Sfp, an enzyme that catalyzes a necessary processing step in the nonribosomal synthesis of lipopeptides and polyketides, but was associated with the aro gene cluster that is involved in the synthesis of the sfp-independent antibiotic bacilysin. Disruption of bacB, the gene in the cluster responsible for synthesizing bacilysin, or supplementation with the antagonist N-acetylglucosamine abolished the inhibitory effect, but this was restored when bacilysin synthesis was complemented. Bacilysin caused apparent changes in the algal cell wall and cell organelle membranes, and this resulted in cell lysis. Meanwhile, there was downregulated expression of glmS, psbA1, mcyB, and ftsZ-genes involved in peptidoglycan synthesis, photosynthesis, microcystin synthesis, and cell division, respectively. In addition, bacilysin suppressed the growth of other harmful algal species. In summary, bacilysin produced by B. amyloliquefaciens FZB42 has anticyanobacterial activity and thus could be developed as a biocontrol agent to mitigate the effects of harmful algal blooms.
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China.
authors.forename: Huijun
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Xie
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China.
authors.forename: Haoyu
authors.initials: H
authors.lastname: Zang
authors.affiliation: ABiTEP GmbH, Berlin, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Borriss
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China gaoxw@njau.edu.cn.
authors.forename: Xuewen
authors.initials: X
authors.lastname: Gao
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000494:pharmacology*; D001407:Bacillus / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004151:Dipeptides / Q000096:biosynthesis / Q000494:pharmacology; D057097:Harmful Algal Bloom / Q000187:drug effects*; D046931:Microcystis / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004151:Dipeptides; C006674:bacilysin