Biocontrol and Other Beneficial Activities of Bacillus subtilis Strains Isolated From Cow Dung, Soil Compost and Soil Rhizosphere Microflora (original) (raw)
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Bacillus subtilis impact on plant growth, soil health and environment: Dr. Jekyll and Mr. Hyde
Journal of Applied Microbiology, 2022
The increased dependence of farmers on chemical fertilizers poses a risk to soil fertility and ecosystem stability. Plant growth-promoting rhizobacteria (PGPR) are at the forefront of sustainable agriculture, providing multiple benefits for the enhancement of crop production and soil health. Bacillus subtilis is a common PGPR in soil that plays a key role in conferring biotic and abiotic stress tolerance to plants by induced systemic resistance (ISR), biofilm formation and lipopeptide production. As a part of bioremediating technologies, Bacillus spp. can purify metal contaminated soil. It acts as a potent denitrifying agent in agroecosystems while improving the carbon sequestration process when applied in a regulated concentration. Although it harbours several antibiotic resistance genes (ARGs), it can reduce the horizontal transfer of ARGs during manure composting by modifying the genetic makeup of existing microbiota. In some instances, it affects the beneficial microbes of the r...
Biocontrol and other beneficial activities of Bacillus subtilis isolated from cowdung microflora
Microbiological Research, 2009
Bacillus subtilis strains isolated from cowdung (CD) had several beneficial attributes, which included biocontrol, plant growth promotion, sulphur (S) oxidation, phosphorus (P) solubilization and production of industrially important enzymes (amylase and cellulase). The B. subtilis strains from CD inhibited the in vitro growth of fungi, Fusarium oxysporum (25-34%) and Botryodiplodia theobromae (100%), isolated from the postharvest rots of yam (Dioscorea rotundata) tubers. Other than biocontrol, B. subtilis strains were able to promote root elongation in seedlings of Cicer arietinum up to 70-74% as compared to untreated seeds (control). B. subtilis strains had also the ability to oxidize elemental S to sulphate (2-15 mg ml À1) and showed distinct P-solubilization activity in vitro. In addition, the cultures showed cellulase activity in carboxy methyl cellulose medium (1.5-1.8 mg of reducing sugar 24 h À1 ml À1) and amylase activity in vitro.
Influence of Bacillus subtilis on soil microbiocenosis
Ecological Questions
The peculiarities of the formation and functioning of the microbial coenosis of podzolized chernozem soil and the intensity of soil-biological processes when using probiotic preparations in different concentrations containing Bacillus subtilis were studied. Probiotic preparations were applied to the soil in different concentrations and doses in separate areas, and the viability of the soil microbial coenosis of agricultural land was assessed in the spring and autumn periods on the 15th and 30th days after the application of the mixtures. The soil without any substances was considered a control option. The analysis of the coefficients of mineralization - immobilization, oligotrophicity and pedotrophicity determined that the use of probiotics helps to increase the content of nutrients in the soil for various ecological and trophic groups of microorganisms, showed that the best result for the functioning of the microbial coenosis of podzolic chernozem soil is observed when using a prob...
On-farm inoculation trials have been conducted to evaluate the potential of Bacillus subtilis NRRL B-30408 in respect of plant growth promotion, for two consecutive years, under rainfed conditions at a mountain location in the Indian Himalayan Region (IHR). For this, one cereal (Oryza sativa) and two millets (Eleusine coracana and Echinochloa frumentacea), were used as test crops. Observations were recorded in terms of plant growth, yield, chlorophyll content, and root colonization by various groups of microorganisms. Positive influence of bacterial inoculation on all the three crops, statistically significant in case of most parameters examined as compared to untreated controls, was recorded in both the years. There was a significant increase in chlorophyll concentration in leaves of inoculated plants. While the bacterial inoculation stimulated the free living bacterial and actinomycetes populations in the rhizosphere, the fungal population was somewhat suppressed; indicative of the antifungal property of the inoculant. The treatment also enhanced the colonization of arbuscular mycorrhizae (AM), and the endophytes associated with the roots. In conclusion, the plant growth promotion, recorded as a result of microbial inoculation, is attributed to the microbial shift in the native microflora of the rhizosphere. Based on the results of this field study, B. subtilis NRRL B-30408 can be proposed as an efficient bioinoculant for the hill crops, grown under rainfed conditions of the mountain ecosystem. The main aim of this study was on farm demonstration of the microbe based technology with peoples' participation, with a view of adoption of the technology by the farmers.
Current Plant Biology, 2019
In sustainable agriculture, integrated plant nutrition management along with a biological agent is an imperative module as a cost-effective and eco-friendly approach against drastic plant hackers (phytopathogens). Bacillus subtilis is one of the most potential biological control agents, because of the broad-spectrum activity of their antibiotics. The current study was carried out to explore in vivo biocontrol efficacy of Bacillus subtilis alone and in combination with plant nutrients [NPK, Zn (1X & 2X), Mg and B] against early blight disease of tomato caused by the necrotrophic fungus Alternaria solani. Results revealed that foliar application of B. subtilis alone and in combination with the plant nutrients managed EB disease significantly by 67-83%, while improved plant growth attributes by 20-77%. B. subtilis and plant nutrients helped the tomato plant to fight off the plant hacker by upregulating the production of total phenolic contents and defensive enzymes (phenylalanine ammonia-lyase, superoxide dismutase, catalase, peroxidase, and polyphenol oxidase). In the current investigation, the light was shed on the interactive effect of microbial agent and positive consequences on plant mineral uptake. It was concluded that integrative use of NPK and Zn (2X) along with B. subtilis have a synergistic impact to manage the disease, improve plant growth, and optimistically enhance physiological and biochemical attributes to contest EB stress in tomato plants.
Biotecnologia Aplicada, 2014
Countries all over the world have experienced the negative impact that phytopathogenic fungi and oomycetes have on food security. Controlling these organisms remains a daunting task due to their genetic plasticity and the large temporal and geographic variability of their populations, which enables them to evolve and develop pesticide-resistant variants despite the considerable effort spent on developing disease-resistant varieties. One strategy for the control of plant diseases is that of biological control using natural enemies of these pests, such as rhizobacteria of the Bacillus and Pseudomonas genera. Bacillus subtilis, in particular, is characterized by the extracellular secretion of a number of antibiotics, microbial lipopeptides and hydrolytic enzymes such as chitinases and proteases that can be harnessed for the control of phytopathogens. The present review describes and examines the advantages and potential applications of B. subtilis strain SR/B-16, originally isolated from the rhizosphere of organically farmed ornamental plants, for the biological control of fungal phytopathogens attacking commercially important crops. In vitro challenging of phytopathogenic fungi with SR/B-16 has demonstrated that the antifungal activity of the latter has a broad spectrum, due to the secretion of metabolites producing structural and ultrastructural changes on the fungal cell. In addition, strain SR/B-16 efficiently colonizes the rhizosphere, which confers it advantages as a potential biopesticide and biofertilizer. Therefore, this microorganism may promote plant growth both by increasing the availability of nitrogen and phosphorous in agricultural soils and by controlling fungal phytopathogens.
On-farm inoculation trials have been conducted to evaluate the potential of Bacillus subtilis NRRL B-30408 in respect of plant growth promotion, for two consecutive years, under rainfed conditions at a mountain location in the Indian Himalayan Region (IHR). For this, one cereal (Oryza sativa) and two millets (Eleusine coracana and Echinochloa frumentacea), were used as test crops. Observations were recorded in terms of plant growth, yield, chlorophyll content, and root colonization by various groups of microorganisms. Positive influence of bacterial inoculation on all the three crops, statistically significant in case of most parameters examined as compared to untreated controls, was recorded in both the years. There was a significant increase in chlorophyll concentration in leaves of inoculated plants. While the bacterial inoculation stimulated the free living bacterial and actinomycetes populations in the rhizosphere, the fungal population was somewhat suppressed; indicative of the antifungal property of the inoculant. The treatment also enhanced the colonization of arbuscular mycorrhizae (AM), and the endophytes associated with the roots. In conclusion, the plant growth promotion, recorded as a result of microbial inoculation, is attributed to the microbial shift in the native microflora of the rhizosphere. Based on the results of this field study, B. subtilis NRRL B-30408 can be proposed as an efficient bioinoculant for the hill crops, grown under rainfed conditions of the mountain ecosystem. The main aim of this study was on farm demonstration of the microbe based technology with peoples' participation, with a view of adoption of the technology by the farmers.
Agriculture, 2021
Recently, crop management has involved excessive use of chemical fertilizers and pesticides, compromising public health and environmental integrity. Rhizobacteria, which can enhance plant growth and protect plants from phytopathogen, are eco-friendly and have been attracting increasing attention. In the current study, Bacillus subtilis RS10 isolated from the rhizosphere region of Cynodon dactylon, inhibited the growth of indicator strains and exhibited in vitro plant growth-promoting traits. A whole-genome analysis identified numerous biosynthetic gene clusters encoding antibacterial and antifungal metabolites including bacillibactin, bogorol A, fengycin, bacteriocin, type III polyketides (PKs), and bacilysin. The plant growth-promoting conferring genes involved in nitrogen metabolism, phosphate solubilization, hydrogen sulfide, phytohormones, siderophore biosynthesis, chemotaxis and motility, plant root colonization, lytic enzymes, and biofilm formation were determined. Furthermore...
Plant and Soil, 2018
Aim Our aim was to investigate factors that influenced bacterial and fungal community composition in the cucumber rhizosphere with the addition of Bacillus subtilis B068150 in soils. Methods Using pyrosequencing, we tracked changes in total bacterial and fungal community composition and structures in cucumber rhizosphere planted in clay, loam and sandy soils and inoculated with B. subtilis B068150. Results B. subtilis B068150 colonized the rhizosphere of cucumber without altering the indigenous microbial community composition. B068150 strain did not significantly affect microbial diversity in cucumber rhizosphere, but both soils texture and chemistry did, based on principal coordinates analysis (PCoA), hierarchical clustering in UniFrac, and canonical correspondence analysis (CCA). Shannon diversity values (H′) suggest that rhizosphere diversity varied among the three soils with the significant highest diversity observed in loamy soil. Fungi were dominated by Ascomycota, Chytridiomycota, Basidiomycotina, with Ascomycota accounting for 29.1%. Fusarium was found only in cucumber rhizosphere grown in loamy soil; however, this did not affect the health of cucumber in three loamy soils during the three months study. Conclusion Bacillus subtilis B068150 could be an environmental compatible plant protective agent in soils depending on the soil type.