Perception of Biocontrol Potential of Bacillus inaquosorum KR2-7 against Tomato Fusarium Wilt through Merging Genome Mining with Chemical Analysis.
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ABSTRACT:
SUBMITTER: Kamali M
PROVIDER: S-EPMC8773019 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Cucumber Fusarium wilt, caused by Fusarium oxysporum, is a devastating disease of cucumber and leads to enormous economic losses worldwide. The antagonistic bacterium Bacillus velezensis NH-1 suppresses F. oxysporum For a higher biological control effect, control-released microcapsules of NH-1 were prepared using cell immobilization technology. NH-1 cells were embedded in combinations of the biodegradable wall materials sodium alginate, chitosan, and cassava-modified starch to prepare control-released microbiological microcapsules. For the preparation of alginate single-layer microcapsules, the highest embedding rate of 72.60% was obtained by applying 3% sodium alginate and 2% calcium chloride. After the application of monolayer alginate microcapsules in soil, the number of bacterial cells corresponded to a sustained release curve, and the survival rate of NH-1 was higher than the control in which soil was directly irrigated with NH-1 broth. The use of 0.8% chitosan (pH 3.0) and 0.5% cassava-modified starch in the preparation of double-layer and triple-layer microcapsules changed the performance of the microcapsules and increased the embedding rate. After dry storage for 65 days, the number of NH-1 cells was at the highest level in the monolayer microcapsules. In the field experiment, the control efficiency of alginate-coated monolayer microcapsules on Fusarium wilt was 100%, which was significantly higher than for the NH-1 culture and double-layer and triple-layer microcapsules. Collectively, sodium alginate is an ideal wall material for preparing slow-release bacterial microcapsules to control cucumber Fusarium wilt. Monolayer alginate microcapsules retard the release of B. velezensis NH-1 in soils and significantly improve its biocontrol efficiency on cucumber Fusarium wilt.IMPORTANCEBacillus species are often used for the biocontrol of various plant pathogens, but the control efficiency of Bacillus is usually unstable in field experiments. To improve the control efficiency of Bacillus, in this study, microcapsules of Bacillus velezensis strain NH-1 were prepared using different wall materials (sodium alginate, chitosan, and cassava-modified starch). It was found that the control efficiency of alginate-coated monolayer microcapsules on Fusarium wilt was 100% in field experiments, which was higher than for NH-1 culture and double-layer and triple-layer microcapsules. This study provides a new approach for preparing a biocontrol agent against Fusarium wilt with high biocontrol efficiency.
| S-EPMC6495769 | biostudies-literature
Project description:In this study, an in vitro antifungal growth experiment showed that the inhibitory rate of the MCF broth on pathogenic fungi (Fusarium oxysporum f. sp. lycopersici, Botrytis cinerea, Trichothecium roseum, and Colletotrichum gloeosporioides) was less than that of B. amyloliquefaciens culture fermentation (BCF). Moreover, the content and gene expression of lipopeptide antibiotics was also lower than that in the BCF group. However, the pot experiments based on irrigation with appropriately diluted fermentation broth showed that the biocontrol effect of MCF on tomato Fusarium wilt was significantly higher than that of TCF (T. longibrachiatum culture fermentation) and BCF, and was approximately 15.79% higher than that of the BTF group which made by mixing equivalent amounts of BCF and TCF. In MCF broth, two microorganisms antagonized and coexisted, and the growth of T. longibrachiatum was inhibited. Using transcriptomic methods, we speculated that MCF can up-regulate the expression of genes related to carbon and nitrogen metabolism, oxidation–reduction activity, sporulation, environmental information response and chemotaxis, and biosynthesis of secondary metabolites of B. amyloliquefaciens, which might enhance the nutrient substances metabolism and competitiveness, survival ability, colonisation, and adaptability to the environment to increase its biocontrol potential.
2021-06-02 | GSE175908 | GEO
Project description:Bacterial wilt disease caused by Ralstonia solanacearum is a widespread, severe plant disease. Tomato (Solanum lycopersicum), one of the most important vegetable crops worldwide, is particularly susceptible to this disease. Biological control offers numerous advantages, making it a highly favorable approach for managing bacterial wilt. In this study, the results demonstrate that treatment with the biological control strain Bacillus subtilis R31 significantly reduced the incidence of tomato bacterial wilt. In addition, R31 directly inhibits the growth of R. solanacearum, and lipopeptides play an important role in this effect. The results also show that R31 can stably colonize the rhizosphere soil and root tissues of tomato plants for a long time, reduce the R. solanacearum population in the rhizosphere soil, and alter the microbial community that interacts with R. solanacearum. This study provides an important theoretical basis for elucidating the mechanism of B. subtilis as a biological control agent against bacterial wilt and lays the foundation for the optimization and promotion of other agents such as R31.
| S-EPMC10568012 | biostudies-literature
Project description:BACKGROUND:There is an urgent need to discover biocontrol agents to control bacterial wilt. This study reports on a new lipopeptide-producing biocontrol strain FJAT-46737 and explores its lipopeptidic compounds, and this study investigates the antagonistic effects of these compounds. RESULTS:Based on a whole genome sequence analysis, the new strain FJAT-46737 was identified as Bacillus velezensis, and seven gene clusters responsible for the synthesis of bioactive secondary metabolites in FJAT-46737 were predicted. The antimicrobial results demonstrated that FJAT-46737 exhibited broad-spectrum antimicrobial activities in vitro against three bacteria and three fungi. Pot experiments showed that the control efficiencies for tomato bacterial wilt of the whole cultures, the 2-fold diluted supernatants and the crude lipopeptide of FJAT-46737 were 66.2%, 82.0%, and 96.2%, respectively. The above results suggested that one of the antagonistic mechanisms of FJAT-46737 was the secretion of lipopeptides consisting of iturins, fengycins and surfactins. The crude lipopeptides had significant antagonistic activities against several pathogens (including Ralstonia solanacearum, Escherichia coli and Fusarium oxysporum) and fengycins were the major antibacterial components of the lipopeptides against R. solanacearum in vitro. Furthermore, the rich organic nitrogen sources (especially yeast extracts) in the media promoted the production of fengycin and surfactin by FJAT-46737. The secretion of these two lipopeptides was related to temperature fluctuations, with the fengycin content decreasing by 96.6% and the surfactins content increasing by 59.9% from 20?°C to 40?°C. The optimal temperature for lipopeptide production by FJAT-46737 varied between 20?°C and 25?°C. CONCLUSIONS:The B. velezensis strain FJAT-46737 and its secreted lipopeptides could be used as new sources of potential biocontrol agents against several plant pathogens, and especially the bacterial wilt pathogen R. solanacearum.
| S-EPMC7296739 | biostudies-literature
Project description:The reduced mycorrhizal colonization (rmc) tomato mutant is unable to form mycorrhiza and is more susceptible to Fusarium wilt compared with its wild-type isogenic line 76R. The rmc mutant has a chromosomal deletion affecting five genes, one of which is similar to CYCLOPS. Loss of this gene is responsible for non-mycorrhizality in rmc but not enhanced Fusarium wilt susceptibility. Here, we describe assessment of a second gene in the rmc deletion, designated Solyc08g075770 that is expressed in roots. Sequence analyses show that Solyc08g075770 encodes a small transmembrane protein with putative phosphorylation and glycosylation sites. It is predicted to be localized in the plasma membrane and may function in transmembrane ion transport and/or as a cell surface receptor. Complementation and knock-out strategies were used to test its function. Some putative CRISPR/Cas-9 knock-out transgenic events exhibited Fusarium wilt susceptibility like rmc and some putative complementation lines were 76R-like, suggesting that the tomato Solyc08g075770 functions in Fusarium wilt tolerance. This is the first study to demonstrate that Solyc08g075770 is the contributor to the Tfw locus, conferring tolerance to Fusarium wilt in 76R which was lost in rmc.
| S-EPMC6003170 | biostudies-literature
Project description:The aim of the present study was to identify a strain of endophytic Bacillus species that control tomato bacterial wilt by foliar spray application. Fifty heat-tolerant endophytic bacteria were isolated from the surface-sterilized foliar tissues of symptomless tomato plants that had been pre-inoculated with the pathogen Ralstonia pseudosolanacearum. In the primary screening, we assessed the suppressive effects of a shoot-dipping treatment with bacterial strains against bacterial wilt on tomato seedlings grown on peat pellets. Bacillus sp. strains G1S3 and G4L1 significantly suppressed the incidence of tomato bacterial wilt. In subsequent pot experiments, the biocontrol efficacy of foliar spray application was examined under glasshouse conditions. G4L1 displayed consistent and significant disease suppression, and, thus, was selected as a biocontrol candidate. Moreover, the pathogen population in the stem of G4L1-treated plants was markedly smaller than that in control plants. A quantitative real-time PCR analysis revealed that the foliar spraying of tomato plants with G4L1 up-regulated the expression of PR-1a and LoxD in stem and GluB in roots upon the pathogen inoculation, implying that the induction of salicylic acid-, jasmonic acid-, and ethylene-dependent defenses was involved in the protective effects of this strain. In the re-isolation experiment, G4L1 efficiently colonized foliar tissues for at least 4? ?weeks after spray application. Collectively, the present results indicate that G4L1 is a promising biocontrol agent for tomato bacterial wilt. Furthermore, to the best of our knowledge, this is the first study to report the biocontrol of bacterial wilt by the foliar spraying with an endophytic Bacillus species.
| S-EPMC7734409 | biostudies-literature
Project description:The discovery of novel biocontrol agents requires the continuous scrutiny of native microorganisms to ensure that they will be useful on a regional scale. The goal of the present work was to discover novel antagonistic bacteria against Fusarium oxysporum ff. spp. lycopersici race 3 (Fol R3) and radicis-lycopersici (Forl) causing Fusarium wilt disease and Fusarium crown and root rot of tomatoes, respectively. High-throughput liquid antagonism screening of 1,875 rhizospheric bacterial strains followed by dual confrontation assays in 96-well plates was used to select bacteria exhibiting > 50% fungal growth inhibition. In a second dual confrontation assay in 10-cm Petri dishes, bacteria showing > 20% Fol R3 or Forl growth inhibition were further screened using a blood hemolysis test. After discarding β-hemolytic bacteria, a seedling antagonistic assay was performed to select five potential antagonists. A phylogenetic analysis of 16S rRNA identified one strain as Acinetobacter calcoaceticus (AcDB3) and four strains as members of the genus Bacillus (B. amyloliquefaciens BaMA26, Bacillus siamensis BsiDA2, B. subtilis BsTA16 and B. thuringiensis BtMB9). Greenhouse assays demonstrated that BsTA16 and AcDB3 were the most promising antagonists against Fol R3 and Forl, respectively. Pathogen biocontrol and growth promotion mechanisms used by these bacteria include the production of siderophores, biofilm, proteases, endoglucanases and indole acetic acid, and phosphate solubilization. These five bacteria exerted differential responses on pathogen control depending on the tomato hybrid, and on the growth stage of tomatoes. We report for the first time the use of an Acinetobacter calcoaceticus isolate (AcDB3) to control Forl in tomato under greenhouse conditions.
| S-EPMC8626321 | biostudies-literature
Project description:One major issue in reducing cucumber yield is the destructive disease Cucumber (Cucumis sativus L.) wilt disease caused by Fusarium oxysporum f. sp. cucumerinum (Foc). When using the isolate VJH504 isolated from cucumber rhizosphere soil and identified as Bacillus velezensis, the growth of Foc in the double culture experiment was effectively inhibited. Phenotypic, phylogenetic, and genomic analyses were conducted to enhance understanding of its biocontrol mechanism. According to the result of the phenotype analysis, B. velezensis VJH504 could inhibit cucumber fusarium wilt disease both in vitro and in vivo, and significantly promote cucumber seed germination and seedling growth. Additionally, the tests of growth-promoting and biocontrol characteristics revealed the secretion of proteases, amylases, β-1,3-glucanases, cellulases, as well as siderophores and indole-3-acetic acid by B. velezensis VJH504. Using the PacBio Sequel II system, we applied the complete genome sequencing for B. velezensis VJH504 and obtained a single circular chromosome with a size of 3.79 Mb. A phylogenetic tree was constructed based on the 16S rRNA gene sequences of B. velezensis VJH504 and 13 other Bacillus species, and Average Nucleotide Identity (ANI) analysis was performed using their whole-genome sequences, confirming isolateVJH504 as B. velezensis. Following this, based on the complete genome sequence od B. velezensis VJH504, specific functional analysis, Carbohydrate-Active Enzymes (CAZymes) analysis, and secondary metabolite analysis were carried out, predicting organism's abilities for biofilm formation, production of antifungal CAZymes, and synthesis of antagonistic secondary metabolites against pathogens. Afterwards, a comparative genomic analysis was performed between B. velezensis VJH504 and three other B. velezensis strains, revealing subtle differences in their genomic sequences and suggesting the potential for the discovery of novel antimicrobial substances in B. velezensis VJH504. In conclusion, the mechanism of B. velezensis VJH504 in controlling cucumber fusarium wilt was predicted to appear that B. velezensis VJH504is a promising biocontrol agent, showcasing excellent application potential in agricultural production.
| S-EPMC10602789 | biostudies-literature
Project description:Since gene expression approaches constitute a starting point for investigating plant-pathogen systems, we performed a transcriptional analysis to identify a set of genes of interest in tomato plants infected with F. oxysporum f. sp. lycopersici (Fol) and Tomato Mosaic Virus (ToMV). Differentially expressed tomato genes upon inoculation with Fol and ToMV were identified at two days post-inoculation. A large overlap was found in differentially expressed genes throughout the two incompatible interactions. However, Gene Ontology enrichment analysis evidenced specific categories in both interactions. Response to ToMV seems more multifaceted, since more than 70 specific categories were enriched versus the 30 detected in Fol interaction. In particular, the virus stimulated the production of an invertase enzyme that is able to redirect the flux of carbohydrates, whereas Fol induced a homeostatic response to prevent the fungus from killing cells. Genomic mapping of transcripts suggested that specific genomic regions are involved in resistance response to pathogen. Coordinated machinery could play an important role in prompting the response, since 60% of pathogen receptor genes (NB-ARC-LRR, RLP, RLK) were differentially regulated during both interactions. Assessment of genomic gene expression patterns could help in building up models of mediated resistance responses.
| S-EPMC4012952 | biostudies-literature
Project description:Bacillus subtilis and other Bacilli have long been used as biological control agents against plant bacterial diseases but the mechanisms by which the bacteria confer protection are not well understood. Our goal in this study was to isolate strains of B.?subtilis that exhibit high levels of biocontrol efficacy from natural environments and to investigate the mechanisms by which these strains confer plant protection. We screened a total of 60 isolates collected from various locations across China and obtained six strains that exhibited above 50% biocontrol efficacy on tomato plants against the plant pathogen Ralstonia solanacearum under greenhouse conditions. These wild strains were able to form robust biofilms both in defined medium and on tomato plant roots and exhibited strong antagonistic activities against various plant pathogens in plate assays. We show that plant protection by those strains depended on widely conserved genes required for biofilm formation, including regulatory genes and genes for matrix production. We provide evidence suggesting that matrix production is critical for bacterial colonization on plant root surfaces. Finally, we have established a model system for studies of B.?subtilis-tomato plant interactions in protection against a plant pathogen.
| S-EPMC3904073 | biostudies-literature