Bacillus subtilis RB14 was used as an antagonist against fungal pathogen Rhizoctonia solani K1 to control damping-off diseases in tomato plants. Tomato seeds were treated with B. subtilis RB14 culture. The concentrati...Bacillus subtilis RB14 was used as an antagonist against fungal pathogen Rhizoctonia solani K1 to control damping-off diseases in tomato plants. Tomato seeds were treated with B. subtilis RB14 culture. The concentration of bacterial cells for the treatment was about 10<sup>8</sup> cfu/ml. Treated tomato seeds showed 99% germination index similar to the untreated seeds. Scanning Electron Microscopic observations showed a clear evidence of the presence of B. subtilis RB14 on tomato seed surface. Clear inhibition zone was observed using treated seed in dual plate assay against R. solani K1. B. subtilis RB14 treated seed showed 80% reduction in disease incidence during in vivo plant experiments. B. subtilis RB14 produces lipopeptide antifungal antibiotic iturin A which could suppress R. solani K1. The phenomenon was supported by our observation where we found significant amount of iturin A from the root zone soil of the seed treated plants.展开更多
The present study was conducted with an aim to scale up the production of iturin A using soybean curd residue (okara). Iturin A was produced by indigenous bacterial strain Bacillus subtilis RB14-CS through glass colum...The present study was conducted with an aim to scale up the production of iturin A using soybean curd residue (okara). Iturin A was produced by indigenous bacterial strain Bacillus subtilis RB14-CS through glass column reactor (GCR) under solid state fermentation (SSF) was characterized. The enhanced iturin A production was observed with respect to enhanced substrate bed height when SSF was conducted in Erlenmeyer flask. To check the effect of substrate bed height on iturin A production under SSF of okara, GCR was introduced. Substrate bed height of 15 cm was suitable for iturin A production which was about 2700 mg/kg wet substrate. The observed iturin A production by the aerobic bacteria Bacillus subtilis in nearly anaerobic condition in such high substrate bed for SSF is a wonderful finding for development of SSF system in future.展开更多
Biocontrol microorganisms and their derived metabolites with antagonistic activity represent promising alternatives to chemical fungicides in managing plant pathogens.The lipopeptides(LPs)iturin and fengycin derived f...Biocontrol microorganisms and their derived metabolites with antagonistic activity represent promising alternatives to chemical fungicides in managing plant pathogens.The lipopeptides(LPs)iturin and fengycin derived from Bacillus amyloliquefaciens S76-3 exhibit highly inhibitory effects against pathogenic fungi,especially Fusarium graminearum(Fg),the primary pathogen causing Fusarium head blight(FHB)in cereals.However,the specific target of iturin and fengycin in Fg and the underlying mechanism of antagonistic activity remain unclear.Here,global transcriptome sequencing,combined with both genetic and chemical approaches,demonstrates that the LPs exhibit antagonism toward Fg by binding to multiple components in the cell membrane of Fg cells,including ergosterol,phospholipids,glycosylphosphatidylinositol,and ankyrin.Lipopeptides result in cell swelling by inducing cell wall remodeling and osmotic substance glycerol synthesis mediated by cell wall integrity and high-osmolarity glycerol signaling pathways.Furthermore,we found that LPs can activate the induced systemic resistance in wheat against FHB and deoxynivalenol accumulation.Additionally,LPs were able to promote wheat growth by regulating auxin,cytokinin,and gibberellin signaling pathways while also delaying seed germination through the stimulation of abscisic acid and ethylene signaling pathways.These findings advance knowledge on the underlying mechanism of iturin and fengycin antagonistic activity and provide a new avenue for developing agricultural and clinical broad-spectrum antifungal agents and identifying plant growth regulators in the future.展开更多
【目的】筛选有效抑制扩展青霉(Penicillium expansum)的拮抗菌,并鉴定其所产抑菌物质的主要种类及相对含量。【方法】从苹果表面分离到拮抗扩展青霉的菌株BA-16,经形态学、生理生化及16S r RNA基因序列分析对该菌进行鉴定;根据已知脂...【目的】筛选有效抑制扩展青霉(Penicillium expansum)的拮抗菌,并鉴定其所产抑菌物质的主要种类及相对含量。【方法】从苹果表面分离到拮抗扩展青霉的菌株BA-16,经形态学、生理生化及16S r RNA基因序列分析对该菌进行鉴定;根据已知脂肽类抗生素合成相关基因序列设计3对特异性引物对菌株BA-16进行检测,对PCR产物克隆、测序和BLAST分析,采用酸沉淀法从菌株发酵液中制备出抑菌物质粗提液,对活性粗提物进行HPLC和MALDI-TOF-MS分析。【结果】经鉴定,BA-16被鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens),所得PCR产物经测序和BLAST分析,证实BA-16带有sfp和fen B基因。HPLC和MS结果显示菌株发酵液中含有Fengycin和Surfactin两种脂肽类产物,Fengycin是拮抗扩展青霉的主要因素。【结论】本研究对于苹果采后青霉病的生物防治具有良好的应用开发前景。展开更多
文摘Bacillus subtilis RB14 was used as an antagonist against fungal pathogen Rhizoctonia solani K1 to control damping-off diseases in tomato plants. Tomato seeds were treated with B. subtilis RB14 culture. The concentration of bacterial cells for the treatment was about 10<sup>8</sup> cfu/ml. Treated tomato seeds showed 99% germination index similar to the untreated seeds. Scanning Electron Microscopic observations showed a clear evidence of the presence of B. subtilis RB14 on tomato seed surface. Clear inhibition zone was observed using treated seed in dual plate assay against R. solani K1. B. subtilis RB14 treated seed showed 80% reduction in disease incidence during in vivo plant experiments. B. subtilis RB14 produces lipopeptide antifungal antibiotic iturin A which could suppress R. solani K1. The phenomenon was supported by our observation where we found significant amount of iturin A from the root zone soil of the seed treated plants.
文摘The present study was conducted with an aim to scale up the production of iturin A using soybean curd residue (okara). Iturin A was produced by indigenous bacterial strain Bacillus subtilis RB14-CS through glass column reactor (GCR) under solid state fermentation (SSF) was characterized. The enhanced iturin A production was observed with respect to enhanced substrate bed height when SSF was conducted in Erlenmeyer flask. To check the effect of substrate bed height on iturin A production under SSF of okara, GCR was introduced. Substrate bed height of 15 cm was suitable for iturin A production which was about 2700 mg/kg wet substrate. The observed iturin A production by the aerobic bacteria Bacillus subtilis in nearly anaerobic condition in such high substrate bed for SSF is a wonderful finding for development of SSF system in future.
基金supported by grants from the National Key R&D Program of China(2022YFD1400102and 2018YFD02005)the National Natural Science Foundation of China(32272170 and 31271717)+1 种基金China Postdoctoral Science Foundation(2021M701348)Hubei Hongshan Laboratory(2022hspy010).
文摘Biocontrol microorganisms and their derived metabolites with antagonistic activity represent promising alternatives to chemical fungicides in managing plant pathogens.The lipopeptides(LPs)iturin and fengycin derived from Bacillus amyloliquefaciens S76-3 exhibit highly inhibitory effects against pathogenic fungi,especially Fusarium graminearum(Fg),the primary pathogen causing Fusarium head blight(FHB)in cereals.However,the specific target of iturin and fengycin in Fg and the underlying mechanism of antagonistic activity remain unclear.Here,global transcriptome sequencing,combined with both genetic and chemical approaches,demonstrates that the LPs exhibit antagonism toward Fg by binding to multiple components in the cell membrane of Fg cells,including ergosterol,phospholipids,glycosylphosphatidylinositol,and ankyrin.Lipopeptides result in cell swelling by inducing cell wall remodeling and osmotic substance glycerol synthesis mediated by cell wall integrity and high-osmolarity glycerol signaling pathways.Furthermore,we found that LPs can activate the induced systemic resistance in wheat against FHB and deoxynivalenol accumulation.Additionally,LPs were able to promote wheat growth by regulating auxin,cytokinin,and gibberellin signaling pathways while also delaying seed germination through the stimulation of abscisic acid and ethylene signaling pathways.These findings advance knowledge on the underlying mechanism of iturin and fengycin antagonistic activity and provide a new avenue for developing agricultural and clinical broad-spectrum antifungal agents and identifying plant growth regulators in the future.
