-
PeerJ 2023genus has been used in horticultural crops as a biocontrol agent against insect pests, microbial phytopathogens, and plant growth-promoting bacteria (PGPB),...
BACKGROUND
genus has been used in horticultural crops as a biocontrol agent against insect pests, microbial phytopathogens, and plant growth-promoting bacteria (PGPB), representing an alternative to agrochemicals. In particular, (Bc) and (Bt) have been studied for their fungicidal and insecticidal activities. However, their use as biofertilizer formulations and biocontrol agents against phytopathogenic bacteria is limited.
OBJECTIVE
To evaluate Bc and Bt formulations as PGPB and biocontrol agents against the bacterial spot agent (Xe) in greenhouse-grown chili peppers.
METHODS
Bc and Bt isolates obtained from soil samples were identified and characterized using conventional biochemical and multiplex PCR identification methods. Bioassays to determine Bc and Bt isolates potential as PGPB were evaluated on chili pepper seedlings in seedbeds. In addition, formulations based on Bc (F-BC26 and F-BC08) and Bt (F-BT24) strains were assessed as biofertilizers on pepper, under controlled conditions. Furthermore, antagonism assays were performed by confronting Bc and Bt isolate formulations against Xe isolates in direct (foliage) and indirect (resistance induction) phytopathogen biocontrol assays on pepper plants, which were grown under controlled conditions for 15 d after formulations treatment.
RESULTS
Isolates were identified as Bc and Bt. Formulations significantly improved pepper growth in seedbeds and pots, whereas bioassays demonstrated the bactericidal effect of Bc and Bt strains against Xe isolates. Furthermore, assays showed significant plant protection by F-BC26, F-BC08, and F-BT24 formulated strains against Xe.
CONCLUSION
Results indicated that F-BT24 and F-BC26 isolates formulations promoted pepper growth and protected it against .
Topics: Bacillus cereus; Bacillus thuringiensis; Bacillus; Crops, Agricultural
PubMed: 36710864
DOI: 10.7717/peerj.14633 -
Microbiology Spectrum Feb 2022Bacillus velezensis HNA3, a potential plant growth promoter and biocontrol rhizobacterium, was isolated from plant rhizosphere soils in our previous work. Here, we... (Comparative Study)
Comparative Study
Bacillus velezensis HNA3, a potential plant growth promoter and biocontrol rhizobacterium, was isolated from plant rhizosphere soils in our previous work. Here, we sequenced the entire genome of the HNA3 strain and performed a comparative genome analysis. We found that HNA3 has a 3,929-kb chromosome with 46.5% GC content and 4,080 CDSs. We reclassified HNA3 as a Bacillus velezensis strain by core genome analysis between HNA3 and 74 previously defined strains in the evolutionary tree. A comparative genomic analysis among Bacillus velezensis HNA3, Bacillus velezensis FZB42, Bacillus amyloliquefaciens DSM7, and Bacillus subtilis 168 showed that only HNA3 has one predicated secretory protein feruloyl esterase that catalyzes the hydrolysis of plant cell wall polysaccharides. The analysis of gene clusters revealed that whole biosynthetic gene clusters type Lanthipeptide was exclusively identified in HNA3 and might lead to the synthesis of new bioactive compounds. Twelve gene clusters were detected in HNA3 responsible for the synthesis of 14 secondary metabolites including Bacillaene, Fengycin, Bacillomycin D, Surfactin, Plipastatin, Mycosubtilin, Paenilarvins, Macrolactin, Difficidin, Amylocyclicin, Bacilysin, Iturin, Bacillibactin, Paenibactin, and others. HNA3 has 77 genes encoding for possible antifungal and antibacterial secreting carbohydrate active enzymes. It also contains genes involved in plant growth promotion, such as 11 putative indole acetic acid (IAA)-producing genes, spermidine and polyamine synthase genes, volatile compound producing genes, and multiple biofilm related genes. HNA3 also has 19 phosphatase genes involved in phosphorus solubilization. Our results provide insights into the genetic characteristics responsible for the bioactivities and potential application of HNA3 as plant growth-promoting strain in ecological agriculture. This study is the primary initiative to identify Bacillus velezensis HNA3 whole genome sequence and reveal its genomic properties as an effective biocontrol agent against plant pathogens and a plant growth stimulator. HNA3 genetic profile can be used as a reference for future studies that can be applied as a highly effective biofertilizer and biofungicide inoculum to improve agriculture productivity. HNA3 reclassified in the phylogenetic tree which may be helpful for highly effective strain engineering and taxonomy. The genetic comparison among HNA3 and closely similar species B. velezensis FZB42, DSM7, and B. subtilis 168 demonstrates some distinctive genetic properties of HNA3 and provides a basis for the genetic diversity of the genus, which allows developing more effective eco-friendly resources for agriculture and separation of Bacillus velezensis as distinct species in the phylogenetic tree.
Topics: Antifungal Agents; Bacillus; Bacterial Proteins; Biological Control Agents; Genome, Bacterial; Genomics; Multigene Family; Phylogeny; Plant Growth Regulators; Secondary Metabolism
PubMed: 35107331
DOI: 10.1128/spectrum.02169-21 -
MicrobiologyOpen Jun 2019The results of this study indicate that the maize rhizosphere remains a reservoir for microbial strains with unique beneficial properties. The study sought to provide an...
The results of this study indicate that the maize rhizosphere remains a reservoir for microbial strains with unique beneficial properties. The study sought to provide an indigenous Bacillus strain with a bioprotective potential to alleviate maize fusariosis in South Africa. We selected seven Bacillus isolates (MORWBS1.1, MARBS2.7, VERBS5.5, MOREBS6.3, MOLBS8.5, MOLBS8.6, and NWUMFkBS10.5) with biosuppressive effects against two maize fungal pathogens (Fusarium graminearum and Fusarium culmorum) based on 16S rDNA gene characterization and lipopeptide gene analysis. The PCR analysis revealed that lipopeptide genes encoding the synthesis of iturin, surfactin, and fengycin might be responsible for their antifungal activities. Few of the isolates also showed possible biosurfactant capability, and their susceptibility to known antibiotics is indicative of their eco-friendly attributes. In addition, in silico genomic analysis of our best isolate (Bacillus velezensis NWUMFkBS10.5) and characterization of its active metabolite with FTIR, NMR, and ESI-Micro-Tof MS confirmed the presence of valuable genes clusters and metabolic pathways. The versatile genomic potential of our Bacillus isolate emphasizes the continued relevance of Bacillus spp. in biological management of plant diseases.
Topics: Bacillus; Fungicides, Industrial; Fusarium; Genome, Bacterial; Lipopeptides; Metabolomics; Phylogeny; Plant Diseases; Zea mays
PubMed: 30358165
DOI: 10.1002/mbo3.742 -
Journal of Bacteriology Apr 2014Spores of Bacillus species can remain in their dormant and resistant states for years, but exposure to agents such as specific nutrients can cause spores' return to life... (Review)
Review
Spores of Bacillus species can remain in their dormant and resistant states for years, but exposure to agents such as specific nutrients can cause spores' return to life within minutes in the process of germination. This process requires a number of spore-specific proteins, most of which are in or associated with the inner spore membrane (IM). These proteins include the (i) germinant receptors (GRs) that respond to nutrient germinants, (ii) GerD protein, which is essential for GR-dependent germination, (iii) SpoVA proteins that form a channel in spores' IM through which the spore core's huge depot of dipicolinic acid is released during germination, and (iv) cortex-lytic enzymes (CLEs) that degrade the large peptidoglycan cortex layer, allowing the spore core to take up much water and swell, thus completing spore germination. While much has been learned about nutrient germination, major questions remain unanswered, including the following. (i) How do nutrient germinants penetrate through spores' outer layers to access GRs in the IM? (ii) What happens during the highly variable and often long lag period between the exposure of spores to nutrient germinants and the commitment of spores to germinate? (iii) What do GRs and GerD do, and how do these proteins interact? (iv) What is the structure of the SpoVA channel in spores' IM, and how is this channel gated? (v) What is the precise state of the spore IM, which has a number of novel properties even though its lipid composition is very similar to that of growing cells? (vi) How is CLE activity regulated such that these enzymes act only when germination has been initiated? (vii) And finally, how does the germination of spores of clostridia compare with that of spores of bacilli?
Topics: Bacillus; Bacterial Proteins; Gene Expression Regulation, Bacterial; Spores, Bacterial
PubMed: 24488313
DOI: 10.1128/JB.01455-13 -
Journal of Applied Microbiology Apr 2008To determine if orally ingested Bacillus spores used as probiotics or direct-fed microbial feed additives germinate and the vegetative cells grow in the gastrointestinal... (Comparative Study)
Comparative Study
AIMS
To determine if orally ingested Bacillus spores used as probiotics or direct-fed microbial feed additives germinate and the vegetative cells grow in the gastrointestinal (GI) tract.
METHODS AND RESULTS
Three independent experiments were done to determine if spores of Bacillus licheniformis and Bacillus subtilis germinate and grow in the GI tract of pigs. After a 2 weeks spore-feeding period, spores were detected in all segments of the GI tract. The lowest number of spores was found in the stomach, increasing in the small intestine to approx. 55% of the dietary inclusion. When spores were withdrawn from the feed, faecal excretion of spores reflected the dietary inclusion, but decreased gradually to the background level after 1 week. By containing spores in short, sealed pieces of dialysis membrane that were orally administered to the pigs, both the number of spores and vegetative cells could be determined by flow cytometry. Spores accounted for 72% of the total counts after 4-6 h in the stomach and proximal part of the small intestine. After 24 h, spores constituted only 12% of the total counts in the stomach, caecum, and mid-colon. Less spores and more vegetative cells were detected after 24 h, but total counts increased only 2.14-fold compared to time zero.
CONCLUSIONS
The experiments showed that 70-90% of dietary-supplemented Bacillus spores germinate in the proximal part of the pig GI tract, and that only limited outgrowth of the vegetative cell population occurs. The two Bacillus strains can temporarily remain in the GI system, but will be unable to permanently colonize the GI tract.
SIGNIFICANCE AND IMPACT OF THE STUDY
A substantial population of growing vegetative cells in the GI tract is not a prerequisite for the mode of action of Bacillus feed additives and probiotics.
Topics: Administration, Oral; Animal Feed; Animals; Bacillus; Bacillus subtilis; Feces; Flow Cytometry; Food Microbiology; Gastrointestinal Tract; Intestine, Small; Microscopy, Phase-Contrast; Probiotics; Spores, Bacterial; Stomach; Swine
PubMed: 18005348
DOI: 10.1111/j.1365-2672.2007.03633.x -
Microbiology Spectrum Sep 2021Bacillus mycoides is poorly known despite its frequent occurrence in a wide variety of environments. To provide direct insight into its ecology and evolutionary history,...
Bacillus mycoides is poorly known despite its frequent occurrence in a wide variety of environments. To provide direct insight into its ecology and evolutionary history, a comparative investigation of the species pan-genome and the functional gene categorization of 35 isolates obtained from soil samples from northeastern Poland was performed. The pan-genome of these isolates is composed of 20,175 genes and is characterized by a strong predominance of adaptive genes (∼83%), a significant amount of plasmid genes (∼37%), and a great contribution of prophages and insertion sequences. The pan-genome structure and phylodynamic studies had suggested a wide genomic diversity among the isolates, but no correlation between lineages and the bacillus origin was found. Nevertheless, the two B. mycoides populations, one from Białowieża National Park, the last European natural primeval forest with soil classified as organic, and the second from mineral soil samples taken in a farm in Jasienówka, a place with strong anthropogenic pressure, differ significantly in the frequency of genes encoding proteins enabling bacillus adaptation to specific stress conditions and production of a set of compounds, thus facilitating their colonization of various ecological niches. Furthermore, differences in the prevalence of essential stress sigma factors might be an important trail of this process. Due to these numerous adaptive genes, B. mycoides is able to quickly adapt to changing environmental conditions. This research allows deeper understanding of the genetic organization of natural bacterial populations, specifically, Bacillus mycoides, a psychrotrophic member of the Bacillus cereus group that is widely distributed worldwide, especially in areas with continental cold climates. These thorough analyses made it possible to describe, for the first time, the B. mycoides pan-genome, phylogenetic relationship within this species, and the mechanisms behind the species ecology and evolutionary history. Our study indicates a set of functional properties and adaptive genes, in particular, those encoding sigma factors, associated with B. mycoides acclimatization to specific ecological niches and changing environmental conditions.
Topics: Anthropogenic Effects; Bacillus; Biological Evolution; DNA Transposable Elements; Ecology; Genome, Bacterial; Genomics; High-Throughput Nucleotide Sequencing; Phylogeny; Plasmids; Sigma Factor; Soil; Soil Microbiology; Species Specificity
PubMed: 34287030
DOI: 10.1128/Spectrum.00311-21 -
Journal of Microbiology and... Dec 2012Genus Bacillus is a spore-forming bacterium that has unique properties in cell differentiation, allowing the forming of spores in stress conditions and activated in the... (Review)
Review
Genus Bacillus is a spore-forming bacterium that has unique properties in cell differentiation, allowing the forming of spores in stress conditions and activated in the vegetative cell, with suitable environments occurring during the life cycle acting as a trigger. Their habitat is mainly in soil; thus, many species of Bacillus are associated with plants as well as rhizosphere bacteria and endophytic bacteria. Signal transduction is the principal mechanism of interactions, both within the cell community and with the external environment, which provides the subsequent functions or properties for the cell. The antimicrobial compounds of Bacillus sp. are potentially useful products, which have been used in agriculture for the inhibition of phytopathogens, for the stimulation of plant growth, and in the food industry as probiotics. There are two systems for the synthesis of these substances: nonribosomal synthesis of cyclic lipopeptides (NRPS) and polyketides (PKS). For each group, the structures, properties, and genes of the main products are described. The different compounds described and the way in which they co-exist exhibit the relationship of Bacillus substances to plants, humans, and animals.
Topics: Bacillus; Bacterial Proteins; Lipopeptides; Microbial Consortia; Peptides, Cyclic; Polyketides; Quorum Sensing; Signal Transduction; Spores, Bacterial
PubMed: 23221520
DOI: 10.4014/jmb.1204.04013 -
Poultry Science Mar 2024This study aimed to evaluate the efficiency and capacity of the probiotic composed of Bacillus subtilis and Bacillus amyloliquefaciens, in improving the zootechnical...
Association of Bacillus subtilis and Bacillus amyloliquefaciens: minimizes the adverse effects of necrotic enteritis in the gastrointestinal tract and improves zootechnical performance in broiler chickens.
This study aimed to evaluate the efficiency and capacity of the probiotic composed of Bacillus subtilis and Bacillus amyloliquefaciens, in improving the zootechnical performance of broiler chickens challenged with Eimeria spp. and Clostridium perfringens. The broilers were distributed in a completely randomized design in poultry isolators (12 birds each), resulting in 3 treatments: T1 (control, no challenge and no Bacillus in diet), T2 (challenged with Eimeria spp., followed by Clostridium perfringens infection and no Bacillus in the diet), and T3 (challenged with Eimeria spp., Clostridium perfringens and treated with Bacillus subtilis and Bacillus amyloliquefaciens). They were evaluated for a period of 29 d, divided into preinitial (1-7 d of age), initial (8-21 d), and growth (22-29 d) phases. Assessments of body weight, weight gain, feed consumption, and feed conversion were conducted, along with the classification of the scores and optical microscopy of the tract gastrointestinal. The animals challenged and treated with the probiotic containing Bacillus spp. showed improved indicators of zootechnical performance. Additionally, the animals challenged and treated (T3) had a better score for intestinal lesions compared to the other treatment groups. Therefore, the probiotic consisting of Bacillus subtilis and Bacillus amyloliquefaciens could be considered an effective option for disease prevention and improving the zootechnical performance of broiler chickens.
Topics: Animals; Bacillus; Bacillus amyloliquefaciens; Bacillus subtilis; Chickens; Clostridium perfringens; Eimeria; Enteritis
PubMed: 38194830
DOI: 10.1016/j.psj.2023.103394 -
Microbiology Spectrum Dec 2021Some species, such as B. velezensis, are important members of the plant-associated microbiome, conferring protection against phytopathogens. However, our knowledge...
Some species, such as B. velezensis, are important members of the plant-associated microbiome, conferring protection against phytopathogens. However, our knowledge about multitrophic interactions determining the ecological fitness of these biocontrol bacteria in the competitive rhizosphere niche is still limited. Here, we investigated molecular mechanisms underlying interactions between and Pseudomonas as a soil-dwelling competitor. Upon their contact-independent confrontation, a multifaceted macroscopic outcome was observed and characterized by growth inhibition, white line formation in the interaction zone, and enhanced motility. We correlated these phenotypes with the production of bioactive secondary metabolites and identified specific lipopeptides as key compounds involved in the interference interaction and motile response. mobilizes its lipopeptide surfactin not only to enhance motility but also to act as a chemical trap to reduce the toxicity of lipopeptides formed by Pseudomonas. We demonstrated the relevance of these unsuspected roles of lipopeptides in the context of competitive tomato root colonization by the two bacterial genera. Plant-associated Bacillus velezensis and Pseudomonas spp. represent excellent model species as strong producers of bioactive metabolites involved in phytopathogen inhibition and the elicitation of plant immunity. However, the ecological role of these metabolites during microbial interspecies interactions and the way their expression may be modulated under naturally competitive soil conditions has been poorly investigated. Through this work, we report various phenotypic outcomes from the interactions between and 10 Pseudomonas strains used as competitors and correlate them with the production of specific metabolites called lipopeptides from both species. More precisely, overproduces surfactin to enhance motility, which also, by acting as a chemical trap, reduces the toxicity of other lipopeptides formed by Pseudomonas. Based on data from interspecies competition on plant roots, we assume this would allow to gain fitness and persistence in its natural rhizosphere niche. The discovery of new ecological functions for and Pseudomonas secondary metabolites is crucial to rationally design compatible consortia, more efficient than single-species inoculants, to promote plant health and growth by fighting economically important pathogens in sustainable agriculture.
Topics: Bacillus; Lipopeptides; Microbial Interactions; Pseudomonas; Secondary Metabolism; Soil Microbiology
PubMed: 34878336
DOI: 10.1128/spectrum.02038-21 -
PloS One 2014Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) despite being increasingly used as a method for microbial identification,...
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) despite being increasingly used as a method for microbial identification, still present limitations in which concerns the differentiation of closely related species. Bacillus pumillus and Bacillus safensis, are species of biotechnological and pharmaceutical significance, difficult to differentiate by conventional methodologies. In this study, using a well-characterized collection of B. pumillus and B. safensis isolates, we demonstrated the suitability of MALDI-TOF-MS combined with chemometrics to accurately and rapidly identify them. Moreover, characteristic species-specific ion masses were tentatively assigned, using UniProtKB/Swiss-Prot and UniProtKB/TrEMBL databases and primary literature. Delineation of B. pumilus (ions at m/z 5271 and 6122) and B. safensis (ions at m/z 5288, 5568 and 6413) species were supported by a congruent characteristic protein pattern. Moreover, using a chemometric approach, the score plot created by partial least square discriminant analysis (PLSDA) of mass spectra demonstrated the presence of two individualized clusters, each one enclosing isolates belonging to a species-specific spectral group. The generated pool of species-specific proteins comprised mostly ribosomal and SASPs proteins. Therefore, in B. pumilus the specific ion at m/z 5271 was associated with a small acid-soluble spore protein (SASP O) or with 50S protein L35, whereas in B. safensis specific ions at m/z 5288 and 5568 were associated with SASP J and P, respectively, and an ion at m/z 6413 with 50S protein L32. Thus, the resulting unique protein profile combined with chemometric analysis, proved to be valuable tools for B. pumilus and B. safensis discrimination, allowing their reliable, reproducible and rapid identification.
Topics: Bacillus; Bacterial Proteins; Bacterial Typing Techniques; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 25314655
DOI: 10.1371/journal.pone.0110127