Bacillus Mojavensis Research Articles

Indole-3-acetic acid-producing Pantoea strain MTP 17 and Glomus mosseae synergistically improve the growth, yield and bacoside content of Bacopa monnieri

The present study aimed to evaluate the performance of Indole-3-acetic acid-producing bacteria (IPB) and arbuscular mycorrhizal fungi (AMF) in compatible form for early establishment and higher growth, yield, and secondary metabolite content of vegetatively propagated Bacopa monnieri plants. Four species of Glomus, viz., G. mosseae (Gm), G. aggregatum (Ga), G. fasciculatum (Gf), G. intraradices (Gi), and two Indole-3-acetic acid-producing bacteria (IPB), Bacillus mojavensis (Bm), and Pantoea sp. (Pt) were evaluated individually and in combinations in a pot experiment. Various plant growth parameters like height, biomass, NPK uptake, mycorrhizal colonization, bacterial population in the rhizosphere, phosphatase activity, and bacoside-A content were determined and found to vary with different treatments. Among all the treatments, plants inoculated with Gm + Pt performed better than any other treatment or un-inoculated control. The performance of the consortium of Gm + Pt was further validated in a field experiment on the same parameters. A clear synergistic interaction between Gm and Pt was observed as Pt enhanced rooting and subsequently improved the colonization and spore population of Gm. On the other hand, the presence of Gm improved the population of Pt in the rhizosphere. The presence of both microbes improved the bacoside-A yields in B. monnieri. The results of this experiment indicate the compatibility and synergy between G. mosseae and Pantoea sp. and suggest using this microbial consortium for plant propagation and growth enhancement while improving soil biological health.

Robust peroxidase from Bacillus mojavensis TH309: Immobilization on walnut shell hydrochar and evaluation of its potential in dye decolorization

Peroxidases have received considerable attention as a cost-effective and environmentally friendly catalyst for bioremediation. Their rapid activity loss under harsh environmental conditions and inability to be used repetitively limit their exploitation in real-world wastewater treatment. First, a peroxidase was produced extracellularly by Bacillus mojavensis TH309 and purified 8.12-fold with a final yield of 47.10 % using Sephadex G-100 superfine resin. The pure peroxidase (BmPer) possessed a relatively low molecular weight of ∼21 kDa and was active against L-DOPA on acrylamide gel after electrophoresis. BmPer was immobilized by adsorption functionalized walnut shell hydrochar (WsH) with 61.99 ± 1.34 % efficiency and 37.07 ± 4.16 % activity loss. BmPer and its immobilized form (WsH-BmPer) exhibited maximum activity at 50 °C and pH 9. WsH-BmPer exhibited 3.23-, 2.37-, 1.65-, and 2.25-fold longer half-life than BmPer at 50, 60, 70, and 80 °C, respectively. Immobilization significantly enhanced the stability of the enzyme under acidic conditions. BmPer and WsH-BmPer showed maximal activity in the presence of 1 % salt and retained more than 85 % of their activity even after pre-incubation with 2.5 M salt for 60 min at 50 °C. Their catalytic efficiency was significantly stimulated by pre-incubation with Triton X-100 (1 mM), Tween20 (1 mM), and Mg2+ (1 and 10 mM). Immobilization strongly reduced the loss of activity caused by inhibitors including Ba2+, Hg2+, and Cu2+. Moreover, both forms of the enzyme were compatible with solvents. The Michaelis constant (Km) values of BmPer and WsH-BmPer were 0.88 and 2.66 mM for 2,4 DCP, respectively. WsH-BmPer peroxidase maintained about 82 % and 85 % of its activity when stored at 4 °C for 30 days and reused for up to 10 cycles, respectively. Furthermore, it decolorized Cibacron red (CR), Poly R-478 (PR), Remazol Brilliant Blue R (RBBR), and Methyl red (MR) dyes by 60.13 %, 91.34 %, 86.41 %, and 50.51 % within 60 min, respectively.

Genome Sequence Resource of Bacillus mojavensis KRS009, a Rhizospheric Microorganism with Biocontrol Potential

Bacillus mojavensis KRS009 was identified as an antagonistic strain with a strong inhibitory effect on various phytopathogenic fungi. To provide further insight into its biocontrol mechanisms and ability to improve plant salt tolerance, the high quality complete genome of KRS009 was sequenced by PacBio platform and assembled using PacBio-HiFiReads. The KRS009 genome consists of one circular chromosome of 4,089,687 bp with 43.5% GC content and 4,062 open reading frames, of which 3,920 protein-coding genes, 86 transfer RNA, 10 ribosomal RNA, and 26 small RNA were identified in this genome. Among them, genes related to compatible solutes, including treC, galU, proX, and proW, are involved in the synthesis of trehalose, proline, and betaine metabolism and play an important role in relieving osmotic stress. In addition, the KRS009 genome contains genes associated with high salinity tolerance, including those responsible for Na+/H+ antiporters, K+ transporters, TrkH thiamin phosphate synthase, K+-sensing histidine kinase, aryl-phospho-beta-D-glucosidase, flavoprotein CzcO associated with the cation diffusion facilitator CzcD, and chaperonin GroEL. Together, the high-quality genome resource of strain KRS009 would provide a molecular basis for further research on its biocontrol and plant salt tolerance mechanisms. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Direct hydrolysis of einkorn whole grain flour proteins for the generation of bioactive peptides using various proteases

In this study, it was aimed to investigate the direct release of BAPs from einkorn flour in one-step process. Thus, the protein extraction step was eliminated, thereby reducing processing cost. Commercial proteases (Alcalase, Flavourzyme, Neutrase, and Trypsin), and crude enzyme from Bacillus mojavensis sp. EBTA7 were used for hydrolyzing einkorn flour (30 %, w/v) solutions at 50–60 °C. The supernatants after centrifugation were used for bioactivity and techno-functionality tests. All hydrolysates demonstrated significant antioxidant capacities, with values ranging from 17.7 to 33.0 μmol TE/g for DPPH, 107 to 190 μmol TE/g for ABTS, and 0.09 to 3.08 mg EDTA/g for ion-chelating activities. Alcalase and Flavourzyme hydrolysis had the highest DPPH activities, while Bacillus mojavensis sp. EBTA7 enzyme yielded relatively high ABTS and ion-chelating activities. Notably, Bacillus mojavensis sp. EBTA7 crude enzyme hydrolysates demonstrated higher oil absorption capacity (2.94 g oil/g hydrolysate), robust emulsion (227 min), and foam stability (94 %) compared to commercial enzymes. FTIR spectroscopy confirmed variations in the secondary structure of peptides. All hydrolysates exhibited negative zeta potentials. The SDS-PAGE showcased MW ranged from 14 to 70 kDa, which was influenced by both the enzyme type and the degree of hydrolysis. Overall, Bacillus mojavensis sp. EBTA7 hydrolysates revealed considerable bio and techno-functional characteristics.

Beneficial effects of Bacillus mojavensis strain MTC-8 on plant growth, immunity and disease resistance against Magnaporthe oryzae.

Rice blast, a prevalent and highly destructive rice disease that significantly impacts rice yield, is caused by the rice blast fungus. In the present study, a strain named MTC-8, identified as Bacillus mojavensis, was demonstrated has strong antagonistic activity against the rice blast fungus, Rhizoctonia solani, Ustilaginoidea virens, and Bipolaria maydis. The potential biocontrol agents were identified using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis and chromatography. Further investigations elucidated the inhibitory mechanism of the isolated compound and demonstrated its ability to suppress spore germination, alter hyphal morphology, disrupt cell membrane integrity, and induce defense-related gene expression in rice. MTC-8 promoted plant growth and may lead to the development of a biocontrol agent that meets agricultural standards. Overall, the Bacillus mojavensis MTC-8 strain exerted beneficial effects on plant growth, immunity and disease resistance against rice blast fungus. In this study, we isolated and purified a bioactive substance from fermentation broth, and the results provide a foundation for the development and application of biopesticides. Elucidation of the inhibitory mechanism against rice blast fungus provides theoretical support for the identification of molecular targets. The successful development of a biocontrol agent lays the groundwork for its practical application in agriculture.

Electrochemical behaviour of thermally treated aluminium 2024 alloy exposed to B. mojavensis

The copper-rich zone plays a key role in understanding the deterioration process of 2024 aluminium alloy. The intermetallic on the surfaces makes this alloy susceptible to both local corrosion and microbial colonization. The adhesion of bacteria on the surface could deteriorate the metallic substrate in a phenomenon known as microbiologically influenced corrosion (MIC). The triggering mechanism of MIC in 2024-T3 is unclear. An electro­chemical study was conducted to determine the influence of the second phase (Al2Cu) on the corrosion of the 2024-T3 aluminium alloy exposed to bacteria. The 2024-T3 alloy was thermally treated to increase the amount of Al2Cu by nearly 67 % on the surface. The bacterium under study was collected from the corrosion products of a Chilean Air Force aircraft. The isolated bacterium was identified by 16S RNA sequencing as Bacillus mojavensis (99.99 %). Results obtained by electrochemical impedance spectroscopy showed a decreased impedance of 2024-T3 and an increased impedance of heat-treated, both samples exposed to bacteria. The increased impedance could be associated with the antibacterial effect due to the high ion release of copper on the surface, which can inhibit biofilm formation and biocorrosion.

Optimization of Plant Nutrition in Aquaponics: The Impact of Trichoderma harzianum and Bacillus mojavensis on Lettuce and Basil Yield and Mineral Status.

The present study aims to test the effect of a nutrient solution, with the addition of microbial inoculum, on the growth and mineral composition of 'Hilbert' and 'Barlach' lettuce cultivars (Lactuca sativa var. crispa, L.) and basil (Ocimum basilicum, L.) cultivated in a vertical indoor farm. These crops were grown in four different variants of nutrient solution: (1) hydroponic; (2) aquaponic, derived from a recirculating aquaculture system (RAS) with rainbow trout; (3) aquaponic, treated with Trichoderma harzianum; (4) aquaponic, treated with Bacillus mojavensis. The benefits of T. harzianum inoculation were most evident in basil, where a significantly higher number of leaves (by 44.9%), a higher nitrate content (by 36.4%), and increased vitamin C (by 126.0%) were found when compared to the aquaponic variant. Inoculation with T. harzianum can be recommended for growing basil in N-limited conditions. B. mojavensis caused a higher degree of removal of Na+ and Cl- from the nutrient solution (243.1% and 254.4% higher, in comparison to the aquaponic solution). This is desirable in aquaponics as these ions may accumulate in the system solution. B. mojavensis further increased the number of leaves in all crops (by 44.9-82.9%) and the content of vitamin C in basil and 'Hilbert' lettuce (by 168.3 and 45.0%) compared to the aquaponic solution. The inoculums of both microbial species used did not significantly affect the crop yield or the activity of the biofilter. The nutrient levels in RAS-based nutrient solutions are mostly suboptimal or in a form that is unavailable to the plants; thus, their utilization must be maximized. These findings can help to reduce the required level of supplemental mineral fertilizers in aquaponics.

Bacillus mojavensis isolated from aguamiel and its potential as a probiotic bacterium

BackgroundMillenary fermented beverages are a source of industrially important microorganisms. Aguamiel and pulque are traditional Mexican beverages of pre-Hispanic origin, with a microbial diversity that contributes to the different fermentations (lactic, alcoholic and acetic). The aim of this research was to characterize the Bacillus mojavensis (BF2A1) strain isolated from aguamiel and determine its probiotic potential. The strain was identified through Mass Spectrometry (MS), molecular techniques, as well as morphological and biochemical profiling. The probiotic activity of the BF2A1 strain and its response during the gastric simulation was determined. ResultsThe strain BF2A1 is a Gram-positive, spore-forming bacillus, positive for catalase, gamma-hemolysis, citrate, ornithine, grows at 7.5% NaCl, and acetoin, but negative for motility, indole, and methyl red. Its taxonomic identity was determined as B. mojavensis both by MALDI-TOF MS and sequencing of 16S rDNA. Its probiotic potential was demonstrated as BF2A1 was tolerant to pH 2 (OD620nm 0.289 ± 0.012), 0.3% bile salts (OD620nm 0.103 ± 0.089), 8% NaCl (OD620nm 0.254 ± 0.096), and 1% lysozyme (OD620nm 1.342 ± 0.078) compared to the probiotic strain Lactobacillus leichmannii ATCC 7830TM (Laclei). The antagonistic effect of BF2A1 against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923), and Candida albicans (ATCC60193) showed 25.5%, 8% and, 65% inhibitory growing effect, respectively. BF2A1 in the gastric simulation showed only a reduction of 1–2 log CFU/mL and showed after the intestinal phase a survival rate of 84.4% as compared to the control strains. ConclusionsThis study shows that BF2A1 isolated from aguamiel is a bacterium with probiotic properties that can be used in different areas of Biotechnology.How to cite: Martínez-Ortiz V, Trujillo-López MA, El-Kassis EG, et al. Bacillus mojavensis isolated from aguamiel and its potential as a probiotic bacterium. Electron J Biotechnol 2024;67. https://doi.org/10.1016/j.ejbt.2023.11.002.

Analysis of Bioactive Compounds Produced by Bacillus mojavensis ZA1 and Their Antagonistic Effect on Colletotrichum coccodes by GC-MS.

The plant disease Colletotrichum coccodes, which lowers potato yields, poses a severe danger to the booming potato industry. Isolated plant endophytic bacteria from highland pasture can produce a variety of metabolites that lessen the risk that the pathogen C. coccodes poses to plant growth and development. Therefore, the objective of our work was to assess substances with antipathogenic properties made by the endophytic bacteria Bacillus mojavensis ZA1. Gas chromatography-mass spectrometry (GC-MS) was used in our investigation to accomplish a thorough structural elucidation of the antipathogenic compounds produced by the endophytic bacterial strain B. mojavensis ZA1. The results showed that the metabolites extracted from ethyl acetate as an extractant were the most effective in inhibiting the pathogen C. coccodes, with 60.95% inhibition. Thirty-five distinct chemicals, including acids, esters, ketones, alcohols, amino acid ammonium salts, cyclic ethers, aromatic hydrocarbons, and heterocyclic compounds, were among the metabolites that may inhibit C. coccodes. Further analysis of the chemical groups in the compound structures revealed the potential of driving groups, such as hydroxyl, carbonyl, ester, benzene, carbon-carbon double bonds, and carbon rings, that prevent C. coccodes from performing its function. This study opens up new opportunities for plant protection programs by demonstrating that natural chemicals produced by B. mojavensis ZA1 can be used as candidates for cutting-edge plant disease management treatments.

Beneficial effects of indigenous Bacillus spp. on growth, antioxidants, immunity and disease resistance of Rhynchocypris lagowskii

This study aimed to investigate the effect of Bacillus aryabhattai (LSG3-7) and Bacillus mojavensis (LSG3-8) on growth performance, antioxidant capacity, and immune response in Rhynchocypris lagowskii (Dybowski, 1869), at the trial and challenge periods. A 630 healthy fish (10.76 ± 0.05) were randomly divided into six groups: control group (D1) was fed the basal diet, D2 and D3 were supplemented with LSG 3–7 and LSG3-8 (1 × 108 CFU/g) for both of them, whereas D4 was supplemented with a mixture of both bacteria (0.5 × 108 CFU/g each), and D5 was supplemented with LSG3-7 0.75 × 108 CFU/g + LSG3-8 0.25 × 108 CFU/g, and D6 supplemented with LSG3-7 0.25 × 108 CFU/g + LSG3-8 0.75 × 108 CFU/g. After the trial, Aeromonas hydrophila was used in a challenge test for 14 days. Treatments showed significant differences (p < 0.05) in growth performance and antioxidant capacity (CAT, CuZn-SOD, GPX) in the liver and intestine compared to the control. The antioxidant-related genes CAT, CuZn-SOD, GPX, and Nrf2 in the liver and intestine showed upregulation compared with the control group. Serum IgM, LZM, C3, C4, and AKP showed a favorable superiority (p < 0.05) in treatments (D2 – D6) at the trial and challenge test compared to controls. In parallel, immune-related genes (IgM, NF-κB, TLR-1, TLR-2, and MyD88) showed an up-regulated level (p < 0.05) in treatments (D2 – D6) compared to the control. In addition, pro-inflammatory cytokines (IL-1, TNF-α) showed a downregulated level in treatments (D2 – D6). After the challenge test, the immune-related genes in the liver and muscle showed an up-regulated level in treatments compared to the controls. The survival rate showed a significant increase (p < 0.05) in the treatment groups (D2 – D6) compared to the control. Overall, individuals and the bacterial mixture of B. aryabhattai and B. mojavensis could improve the growth performance, antioxidant capacity, immune capacity, and survival rate of R. lagowskii and prevent side effects of A. hydrophila. However, B. mojavensis showed a slight improvement compared to B. aryabhattai without a significant difference between them.

Plant growth-promoting and heavy metal-resistant Priestia and Bacillus strains associated with pioneer plants from mine tailings.

Open mine tailings dams are extreme artificial environments containing sizeable potentially toxic elements (PTEs), including heavy metals (HMs), transition metals, and metalloids. Furthermore, these tailings have nutritional deficiencies, including assimilable phosphorus sources, organic carbon, and combined nitrogen, preventing plant colonization. Bacteria, that colonize these environments, have mechanisms to tolerate the selective pressures of PTEs. In this work, several Priestia megaterium (formerly Bacillus megaterium), Bacillus mojavensis, and Bacillus subtilis strains were isolated from bulk tailings, anthills, rhizosphere, and endosphere of pioneer plants from abandoned mine tailings in Zacatecas, Mexico. Bacillus spp. tolerated moderate HMs concentrations, produced siderophores and indole-3-acetic acid (IAA), solubilized phosphates, and reduced acetylene in the presence of HMs. The strains harbored different PIB-type ATPase genes encoding for efflux pumps and Cation Diffusion Facilitator (CDF) genes. Moreover, nifH and nifD nitrogenase genes were detected in P. megaterium and B. mojavensis genomic DNA. They showed similarity with sequences of the beta-Proteobacteria species, which may represent likely horizontal transfer events. These Bacillus species precede the colonization of mine tailings by plants. Their phenotypic and genotypic features could be essential in the natural recovery of the sites by reducing the oxidative stress of HMs, fixing nitrogen, solubilizing phosphate, and accumulating organic carbon. These traits of the strains reflect the adaptations of Bacillus species to the mine tailings environment and could contribute to the success of phytoremediation efforts.

Evaluation of Bioremediation Potentiality of Bacillus mojavensis Isolated from Wastewater for the Elimination of Reactive Yellow 145 and Methyl Orange.

Textile industry waste has become one of the largest polluters in the world. In recent years, there has been a growing awareness of the need for sustainable and eco-friendly practices for the treatment of dye-laden effluents. Overall, this study highlights the potential of bioremediation as a sustainable solution for wastewater treatment. The Bacillus mojavensis isolated from wastewater and identified using 16S rRNA degraded reactive yellow 145 and methyl orange in 36h of incubation, this decolorization was affected by pH, temperature, dye concentration, glucose concentration, source of nitrogen, type of dye, and agitation. Our study found that the optimal conditions for total decolorization of dyes were achieved by incubating B. mojavensis at 46°C, pH 9, with 1g/L of glucose and 2g/L of peptone. The azoreductase activity, FT-IR analysis, and UV-visible spectrum before and after total decolorization indicated that it was a dye degradation rather than biosorption in surface Celle. In addition, the study of phytotoxicity show the metabolites of degradation are not phytotoxic in Lens esculenta seeds. In conclusion, our results suggest the use of this bacterium as an environmentally friendly and also cost-effective method, making it an attractive option for industries looking to reduce their environmental impact.

Suppression of tomato bacterial speck disease (Pseudomonas syringae pv. tomato (Okabe) Young, Dye, &amp; Wilkie) via induced systemic resistance by Pseudomonas and Bacillus strains

Bacterial speck Pseudomonas syringae pv. tomato (Pst) (Okabe) Young, Dye, &amp; Wilkie is a widespread disease in tomato plants. Four plant growth-promoting rhizobacterial (PGPR) strains 5(3), 68(2), 36(1), and 47(3) played a significant role (50% and higher) in reducing spot disease severity. Selected strains were identified as Pseudomonas koreensis 5(3), Bacillus mycoides 68(2), Bacillus mojavensis 36(1), and Bacillus simplex 47(3) using the MALDI Biotyper classification system. In planta assay using tomato seedlings were inoculated with the bacterial strains alone or in dual combination. Pseudomonas koreensis 5(3) (51.9%–74.29%) and Bacillus mycoides 68(2) (36.70%–65.56%) both provided a significant reduction in foliar severity caused by bacterial speck disease agent Pseudomonas syringae pv. tomato (Okabe) Young, Dye, &amp; Wilkie. Bacillus simplex 47(3) and Bacillus mojavensis 36(1) were successful only in combined treatments. Defense enzymes Proline, Peroxidase, and Catalase were induced by PGPR strains in comparison with those of control plants. Hydrogen peroxide (H2O2) and callose deposition were evident at reaction sites induced by PGPR strains. The accumulation of callose, H2O2, and high levels of defense enzymes via the treatment of PGPRs might play a significant role in a practical, safe, and effective way to control Pseudomonas syringae pv. tomato.

Isolation and screening of keratinase enzyme producing Bacillus mojavensis par01 from poultry farm

Isolation and screening of keratinase enzyme producing Bacillus mojavensis par01 from poultry farm

Antifungal mechanisms of the antagonistic bacterium Bacillus mojavensis UTF-33 and its potential as a new biopesticide.

Biological control has gradually become the dominant means of controlling fungal disease over recent years. In this study, an endophytic strain of UTF-33 was isolated from acid mold (Rumex acetosa L.) leaves. Based on 16S rDNA gene sequence comparison, and biochemical and physiological characteristics, this strain was formally identified as Bacillus mojavensis. Bacillus mojavensis UTF-33 was sensitive to most of the antibiotics tested except neomycin. Moreover, the filtrate fermentation solution of Bacillus mojavensis UTF-33 had a significant inhibitory effect on the growth of rice blast and was used in field evaluation tests, which reduced the infestation of rice blast effectively. Rice treated with filtrate fermentation broth exhibited multiple defense mechanisms in response, including the enhanced expression of disease process-related genes and transcription factor genes, and significantly upregulated the gene expression of titin, salicylic acid pathway-related genes, and H2O2 accumulation, in plants; this may directly or indirectly act as an antagonist to pathogenic infestation. Further analysis revealed that the n-butanol crude extract of Bacillus mojavensis UTF-33 could retard or even inhibit conidial germination and prevent the formation of adherent cells both in vitro and in vivo. In addition, the amplification of functional genes for biocontrol using specific primers showed that Bacillus mojavensis UTF-33 expresses genes that can direct the synthesis of bioA, bmyB, fenB, ituD, srfAA and other substances; this information can help us to determine the extraction direction and purification method for inhibitory substances at a later stage. In conclusion, this is the first study to identify Bacillus mojavensis as a potential agent for the control of rice diseases; this strain, and its bioactive substances, have the potential to be developed as biopesticides.

Characterization of Bacillus spp. isolated from the intestines of Rhynchocypris lagowskii as a potential probiotic and their effects on fish pathogens

Probiotics sourced from fish intestinal microbiota have a merit over other bacterial sources due to colonization ability and effective time. This study aimed to evaluate the bacilli isolated from the Rhynchocypris lagowskii intestines and their validity as a probiotic. Three isolates were selected (LSG 2–5, LSG 3–7, and LSG 3–8) and defined by morphological and 16S rRNA analysis as Bacillus velezensis, Bacillus aryabhattai, and Bacillus mojavensis, respectively. Results showed the strain tolerant abilities to gastrointestinal fluid, bile salt, pH, and temperature expotures. Additionally, all bacterial strains showed anti-pathogenic activity against at least four strains out of six tested pathogen strains (Staphylococcus aureus, Aeromonas hydrophila, Escherichia coli, Aeromonas veronii, Edwardsiella, and Aeromonas sobria). The bacterial strains also showed a high percentage of co-aggregation activity, more than 70%, with Aer. hydrophile, Staph. epidermidis, and Klebsiella aerogenes. At the same time, the results of competition, rejection, and substitution activity with Aer. hydrophila and Aer. veronii indicated the ability of the isolated strains to reduce the adhesion of pathogens to mucin. All strains showed safety properties, non-hemolytic, and sensitivity characteristics for most of tested antibiotics. In vivo test after injecting these strains into fish at various concentrations showed no side effects in the internal or external organs of fish compared to controls, proving that this is safe for these fish. Furthermore, the three strains produced lipase, amylase, and protease enzymes. The strains also showed bile salt hydrolase activity and biofilm formation, allowing them to tolerate stressful conditions. Conclusion: Based on these strains characteristics and features, they could be considered a promising candidate probiotic and can be used as an anti-pathogenic, especially in aquaculture.

Adding Metal Ions to the Bacillus mojavensis D50 Promotes Biofilm Formation and Improves Ability of Biocontrol

Bacillus mojavensis D50, a biocontrol strain, is used to prevent and treat the fungal plant pathogen Botrytis cinerea. Bacillus mojavensis D50's biofilms can affect its colonization; thus, the effects of different metal ions and culture conditions on biofilm formation were determined in this study. The results of medium optimization showed that Ca2+ had the best ability to promote biofilm formation. The optimal medium composition for the formation of biofilms contained tryptone (10 g/L), CaCl2 (5.14 g/L), and yeast extract (5.0 g/L), and the optimal fermentation conditions included pH 7, a temperature of 31.4 °C, and a culture time of 51.8 h. We found that the antifungal activity and abilities to form biofilms and colonize roots were improved after optimization. In addition, the levels of expression of the genes luxS, SinR, FlhA, and tasA were up-regulated by 37.56-, 2.87-, 12.46-, and 6.22-fold, respectively. The soil enzymatic activities which related biocontrol-related enzymes were the highest when the soil was treated by strain D50 after optimization. In vivo biocontrol assays indicated that the biocontrol effect of strain D50 after optimization was improved.

The Plant Growth-Promoting Bacteria Strain Bacillus mojavensis I4 Enhanced Salt Stress Tolerance in Durum Wheat.

Plant growth and production are adversely affected by soil salinity. A plant growth-promoting bacteria (PGPB) designated as the "I4 strain" of Bacillus mojavensis was isolated from Tunisian soil (Sfax, Tunisia) and showed the ability to be grown in the presence of NaCl concentrations ranging from 0 to 10% in Luria Bertani (LB) medium. The PGPB-mediated salt tolerance in durum wheat was evaluated. The physiological parameters such as growth, shoot and root length, dry and fresh weight were higher in I4-inoculated wheat plants in comparison with non-treated plants under salt stress. Results showed that this strain promoted wheat growth and preserved the membrane damage by notably lowering the electrolytes leakage and malondialdehyde content in contrast to non-inoculated plants. Moreover, leaf chlorophyll content, biochemical parameters and antioxidant enzyme activities measurement showed a better salt and heavy metal stress adaptation of the I4-inoculated plants. Due to these outcomes, it could be suggested that the inoculation of the PGPB I4 strain enhanced the wheat plant's growth, especially under salt stress conditions. This study confirms the ameliorative role played by PGPB in tolerating salt stress in wheat and their potential use as biofertilizers to enhance its growth in saline soil and help in promoting this plant's culture to provide food security under these perturbed global circumstances.

ОЦЕНКА ВЛИЯНИЯ ПРИМЕНЕНИЯ БИОПРЕПАРАТОВ В ПЕРИОД ВЕГЕТАЦИИ НА МИКРОБИОМ СЕМЯН ЯРОВОЙ ПШЕНИЦЫ

An assessment is made of the effect of spraying plants with biological products on the total microbiome of seeds of a new crop. The studies were carried out on three varieties of spring wheat of domestic breeding - Yoldyz, Burlak and Ulyanovsk-105. Preparations based on strains of endophytic bacteria isolated from seeds of spring wheat (Bacillus mojavensis PS17, Bacillus velezensis KS25) and spring barley (Bacillus velezensis KS31, Bacillus subtilis KS38) were used as biological preparations. The treatment of spring wheat crops was carried out in the phase of entry into the tube using the biological product consumption rate of 1.0 l/ha. The impact of treatments on the fungal and bacterial microbiome was assessed using quantitative PCR methods with the determination of the total (total) DNA of microorganisms per unit weight of seeds. In most cases, the use of treatment with endophytic bacteria reduces the amount of total micromycete DNA on seeds. Among the studied isolates, the Bacillus subtilis KS-38 strain was especially distinguished, which provided a significant (7.7-11.1 times) decrease in this indicator in all varieties. Bacillus mojavensis PS-17 had a significant effect (a decrease of almost 47 times) on the Ulyanovska 105 variety, and Bacillus velezensis KS-31 on the Burlak variety. On varieties Yoldyz and Ulyanovska 105, the most significant decrease in the total DNA of micromycetes was noted for endophytes obtained from spring wheat seeds (Bacillus mojavensis PS-17, Bacillus velezensis KS-25), and on variety Burlak, endophytes from spring barley seeds (Bacillus velezensis KS-31 and Bacillus subtilis KS-38). The decrease in the total DNA of micromycetes in the experiments was due to the use of the studied biological products and, to a lesser extent, varietal characteristics. For the bacterial microbiome, there were strong differences between varieties. A significant increase in the total DNA of bacteria in all studied varieties was in Bacillus mojavensis PS-17 and Bacillus velezensis KS-31. The variety (29.9%) made the greatest contribution to the variability in the content of total bacterial DNA in seeds, and the contribution of biological preparations was lower (25.5%). In the experiments, no correlation was found between the indicators of the total DNA of micromycetes and bacteria in spring wheat seeds.

EFFICIENCY OF NITROGEN FIXING, NODULATION FORMATION, PHOSPHATE SOLUBILIZING BACTERIA AND PLANT GROWTH PROMOTING RHIZOBACTERIA ON YIELD OF CHICKPEA

Chickpea is an important nodules producing pulse crop of Thal. To enhance nitrogen fixation for higher yield, the effect of bacterial strains on nodulation was evaluated for yield contributing traits of chickpea at Arid Zone Research Institute, Bhakkar, Pakistan during 2019-20. Six Rhizobium inoculations i.e. Providencia vermicola, Enterobacter cloacae, Bacillus mojavensis, Mesorhizobium ciceri-11, Mesorhizobium ciceri-1 and Bacillus subtilis were tested on two chickpea genotypes i.e. Bhakkar-2011 and Thal-2020. A consortium of six bacterial strains was applied at the time of sowing as a seed coating on a sandy soil. Results showed a significant increase in height/plant, nodulation, 100 grain weight, pods/plant and grain yield (kg/ha) due to bacterial inoculation. Nodules/plant were also increased from 44.08 to 76.16. Maximum number of nodules plant-1 were counted as 76.16 with 2.59 g fresh and 0.64 g dry weight per plant in treatment combination viz. Thal-2020 × RP08+RS14+RZ11 thus showing the specific symbiotic relationship among the genotypes and Rhizobium inoculum. In comparison to the control, the PSB, nitrogen-fixing bacteria and rhizobium inoculum results were 52 % increase in pods/ plant. The maximum number of pods/plant (116.00) and100 grain weight (27.73 g) were recorded in V1 × T1 (RP08+RS14+ RZ11). The weight of 100 grains was increased by 40% over the control. T1 had the highest 100 grain weight of 27.73 g, followed by V1 x T3 with a 100 grain weight of 26.22 g. PSB, nitrogen fixation bacteria and PSB inoculation substantially improved pulse crop 100 grain weight and yield. Thal-2020 had the highest grain yield of 3732 kg/ha, while V2 (Bhakkar-2011) had the lowest at 3516 kg/ha. Inoculation with rhizobium consortium improved grain yield by 30% (2617 to 3732 kg/ha). Hence, it was concluded that among all the treatments of Rhizobium consortium, N-fixing bacteria and PSB influenced a beneficial effect on chickpea grain yield quality and quantity.