The highly modified microcin peptide plantazolicin is associated with nematicidal activity of Bacillus amyloliquefaciens FZB42

Abstract

Bacillus amyloliquefaciens FZB42 has been shown to stimulate plant growth and to suppress the growth of plant pathogenic organisms including nematodes. However, the mechanism underlying its effect against nematodes remains unknown. In this study, we screened a random mutant library of B. amyloliquefaciens FZB42 generated by the mariner transposon TnYLB-1 and identified a mutant strain F5 with attenuated nematicidal activity. Reversible polymerase chain reaction revealed that three candidate genes RAMB_007470, yhdY, and prkA that were disrupted by the transposon in strain F5 potentially contributed to its decreased nematicidal activity. Bioassay of mutants impaired in the three candidate genes demonstrated that directed deletion of gene RBAM_007470 resulted in loss of nematicidal activity comparable with that of the F5 triple mutant. RBAM_007470 has been reported as being involved in biosynthesis of plantazolicin, a thiazole/oxazole-modified microcin with hitherto unknown function. Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) analyses of surface extracts revealed that plantazolicin bearing a molecular weight of 1,354 Da was present in wild-type B. amyloliquefaciens FZB42, but absent in the ΔRABM_007470 mutant. Furthermore, bioassay of the organic extract containing plantazolicin also showed a moderate nematicidal activity. We conclude that a novel gene RBAM_007470 and its related metabolite are involved in the antagonistic effect exerted by B. amyloliquefaciens FZB42 against nematodes.

Bacilysin from Bacillus amyloliquefaciens FZB42 Has Specific Bactericidal Activity against Harmful Algal Bloom Species

“…Prominent classes of such compounds are the sfp-dependent lipopeptides and polyketides which need Sfp, a 4=-phosphopantetheinyl transferase to transfer 4=-phosphopantetheine from coenzyme A onto peptidyl carrier proteins in the nonribosomal peptide synthesis pathway (22). Lipopeptides consist of a lipid connected to a peptide, and these are largely (27,28). In the present study, we report that B. amyloliquefaciens FZB42 displays high inhibitory activity against M. aeruginosa.…”

“…The non-ribosomally synthesized lipopeptides (e.g., surfactin, fengycin, and bacillomycin D) and polyketides (e.g., bacillaene, difficidin, and macrolactin) exhibit potent antifungal, hemolytic, and antibacterial activities (24)(25)(26). Meanwhile, the ribosomally synthesized peptide antibiotics plantazolicin A and B show moderate nematicidal activity (27,28). In the present study, we report that B. amyloliquefaciens FZB42 displays high inhibitory activity against M. aeruginosa.…”

Identification and classification of known and putative antimicrobial compounds produced by a wide variety of Bacillales species

“…Plantazolicin A (Additional file 2: Table S2) and its desmethyl analogue plantazolicin B represent an unusual type of thioazole/oxazole-containing peptide antibiotic with a hitherto unknown mechanism of action, which show inhibition against Bacillus [80, 87]. The mature product plantazolicin is a linear 41 amino acid precursor peptide with the 14 amino acid core-peptide encoded by the structural gene pznA .…”

Plantazolicin Is an Ultranarrow-Spectrum Antibiotic That Targets the Bacillus anthracis Membrane

“…described a nematicidal activity to PZN, derived from experiments showing that PZN-deficient FZB42 strains exhibit reduced nematicidal activity against Caenorhabditis elegans . (33) Since these experiments employed crude cellular extracts, we evaluated purified PZN in a similar manner, embedding the compound in agar (“slow killing” assay) or providing PZN in a liquid suspension (“liquid fast killing” assay). PZN was found to be no more toxic to C. elegans than a vehicle control and is not nematicidal in its own right (Figure S3).…”