Bacillus velezensis FZB42, the model strain for Gram-positive plant-growth-promoting and biocontrol rhizobacteria, has been isolated in 1998 and sequenced in 2007. In order to celebrate these anniversaries, we summarize here the recent knowledge about FZB42. In last 20 years, more than 140 articles devoted to FZB42 have been published. At first, research was mainly focused on antimicrobial compounds, apparently responsible for biocontrol effects against plant pathogens, recent research is increasingly directed to expression of genes involved in bacteria–plant interaction, regulatory small RNAs (sRNAs), and on modification of enzymes involved in synthesis of antimicrobial compounds by processes such as acetylation and malonylation. Till now, 13 gene clusters involved in non-ribosomal and ribosomal synthesis of secondary metabolites with putative antimicrobial action have been identified within the genome of FZB42. These gene clusters cover around 10% of the whole genome. Antimicrobial compounds suppress not only growth of plant pathogenic bacteria and fungi, but could also stimulate induced systemic resistance (ISR) in plants. It has been found that besides secondary metabolites also volatile organic compounds are involved in the biocontrol effect exerted by FZB42 under biotic (plant pathogens) and abiotic stress conditions. In order to facilitate easy access to the genomic data, we have established an integrating data bank ‘AmyloWiki’ containing accumulated information about the genes present in FZB42, available mutant strains, and other aspects of FZB42 research, which is structured similar as the famous SubtiWiki data bank.
Bacterial volatiles play a significant role in promoting plant growth by regulating the synthesis or metabolism of phytohormones. In vitro and growth chamber experiments were conducted to investigate the effect of volatile organic compounds (VOCs) produced by the plant growth promoting rhizobacterium Bacillus subtilis strain SYST2 on hormone regulation and growth promotion in tomato plants. We observed a significant increase in plant biomass under both experimental conditions; we observed an increase in photosynthesis and in the endogenous contents of gibberellin, auxin, and cytokinin, while a decrease in ethylene levels was noted. VOCs emitted by SYST2 were identified through gas chromatography-mass spectrometry analysis. Of 11 VOCs tested in glass jars containing plants in test tubes, only two, albuterol and 1,3-propanediole, were found to promote plant growth. Furthermore, tomato plants showed differential expression of genes involved in auxin (SlIAA1. SlIAA3), gibberellin (GA20ox-1), cytokinin (SlCKX1), expansin (Exp2, Exp9. Exp 18), and ethylene (ACO1) biosynthesis or metabolism in roots and leaves in response to B. subtilis SYST2 VOCs. Our findings suggest that SYST2-derived VOCs promote plant growth by triggering growth hormone activity, and provide new insights into the mechanism of plant growth promotion by bacterial VOCs.
Volatile organic compounds (VOCs) produced by various bacteria have significant potential to enhance plant growth and to control phytopathogens. Six of the most effective antagonistic Bacillus spp. were used in this study against Ralstonia solanacearum (Rsc) TBBS1, the causal agent of bacterial wilt disease in tobacco. Bacillus amyloliquefaciens FZB42 and Bacillus artrophaeus LSSC22 had the strongest inhibitory effect against Rsc. Thirteen VOCs produced by FZB42 and 10 by LSSC22 were identified using gas chromatography-mass spectrometry analysis. Benzaldehyde, 1,2-benzisothiazol-3(2 H)-one and 1,3-butadiene significantly inhibited the colony size, cell viability, and motility of pathogens and negatively influenced chemotaxis. Transmission and scanning electron microscopy revealed severe morphological and ultra-structural changes in cells of Rsc. Furthermore, VOCs altered the transcriptional expression level of PhcA (a global virulence regulator), type III secretion system (T3SS), type IV secretion system (T4SS), extracellular polysaccharides and chemotaxis-related genes, which are major contributors to pathogenicity, resulting in decreased wilt disease. The VOCs significantly up-regulated the expression of genes related to wilt resistance and pathogen defense. Over-expression of EDS1 and NPR1 suggest the involvement of SA pathway in induction of systemic resistance. Our findings provide new insights regarding the potential of antibacterial VOCs as a biocontrol tool against bacterial wilt diseases.
(teleomorph: Ascomycota, Hypocreales, ,) is a destructive fungal pathogen that threatens the production and quality of wheat and barley worldwide. Controlling this toxin-producing pathogen is a significant challenge. In the present study, the commercially available strain (, ,, ) FZB42 showed strong activity against The lipopeptide bacillomycin D, produced by FZB42, was shown to contribute to the antifungal activity. Purified bacillomycin D showed strong activity against , and its 50% effective concentration was determined to be approximately 30 μg/ml. Analyses using scanning and transmission electron microscopy revealed that bacillomycin D caused morphological changes in the plasma membranes and cell walls of hyphae and conidia. Fluorescence microscopy combined with different dyes showed that bacillomycin D induced the accumulation of reactive oxygen species and caused cell death in hyphae and conidia. secondary metabolism also responded to bacillomycin D challenge, by increasing the production of deoxynivalenol. Biological control experiments demonstrated that bacillomycin D exerted good control of on corn silks, wheat seedlings, and wheat heads. In response to bacillomycin D, genes involved in scavenging reactive oxygen species were downregulated, whereas genes involved in the synthesis of deoxynivalenol were upregulated. Phosphorylation of MGV1 and HOG1, the mitogen-activated protein kinases of , was increased in response to bacillomycin D. Taken together, these findings reveal the mechanism of the antifungal action of bacillomycin D. Biological control of plant disease caused by is desirable. FZB42 is a representative of the biocontrol bacterial strains. In this work, the lipopeptide bacillomycin D, produced by FZB42, showed strong fungicidal activity against Bacillomycin D caused morphological changes in the plasma membrane and cell wall of, induced accumulation of reactive oxygen species, and ultimately caused cell death in Interestingly, when was challenged with bacillomycin D, the deoxynivalenol production, gene expression, mitogen-activated protein kinase phosphorylation, and pathogenicity of were significantly altered. These findings clarified the mechanisms of the activity of bacillomycin D against and highlighted the potential of FZB42 as a biocontrol agent against.
The interaction between plants and plant-growth-promoting rhizobacteria (PGPR) is a complex, reciprocal process. On the one hand, plant compounds such as carbohydrates and amino acids serve as energy sources for PGPR. On the other hand, PGPR promote plant growth by synthesizing plant hormones and increasing mineral availability in the soil. Here, we evaluated the growth-promoting activity of Bacillus subtilis OKB105 and identified genes associated with this activity. The genes yecA (encoding a putative amino acid/polyamine permease) and speB (encoding agmatinase) are involved in the secretion or synthesis of polyamine in B. subtilis OKB105. Disruption of either gene abolished the growth-promoting activity of the bacterium, which was restored when polyamine synthesis was complemented. Moreover, high-performance liquid chromatography analysis of culture filtrates of OKB105 and its derivatives demonstrated that spermidine, a common polyamine, is the pivotal plant-growth-promoting compound. In addition, real-time polymerase chain reaction analysis revealed that treatment with B. subtilis OKB105 induced expansin gene (Nt-EXPA1 and Nt-EXPA2) expression and inhibited the expression of the ethylene biosynthesis gene ACO1. Furthermore, enzyme-linked immunosorbent assay analysis showed that the ethylene content in plant root cells decreased in response to spermidine produced by OKB105. Therefore, during plant interactions, OKB105 may produce and secrete spermidine, which induces expansin production and lowers ethylene levels.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.