Characterization of a Bacillus velezensis strain isolated from Bolbostemmatis Rhizoma displaying strong antagonistic activities against a variety of rice pathogens

Abstract

Biological control is an effective measure in the green control of rice diseases. To search for biocontrol agents with broad-spectrum and high efficiency against rice diseases, in this study, a strain of antagonistic bacterium BR-01 with strong inhibitory effect against various rice diseases was isolated from Bolbostemmatis Rhizoma by plate confrontation method. The strain was identified as Bacillus velezensis by morphological observation, physiological and biochemical identification, and molecular characterization by 16S rDNA and gyrB gene sequencing analysis. The confrontation test (dual culture) and Oxford cup assays demonstrated that B. velezensis BR-01 had strong antagonistic effects on Magnaporthe oryzae, Ustilaginoidea virens, Fusarium fujikuroi, Xanthomonas oryzae pv. Oryzicola, and Xanthomonas oryzae pv. oryzae, the major rice pathogens. The genes encoding antimicrobial peptides (ituA, ituD, bmyB, bmyC, srfAA, fenB, fenD, bacA, and bacD) were found in B. velezensis BR-01 by PCR amplification with specific primers. B. velezensis BR-01 could produce protease, cellulase, β-1,3-glucanase, chitinase, indoleacetic acid, siderophore, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and might produce three lipopeptide antibiotics, surfactin, iturin, and fengycin based on Liquid chromatography–mass spectrometry (LC-MS) results. Furthermore, the plant assays showed that B. velezensis BR-01 had significant control effects on rice bacterial blight and bacterial leaf streak by pot experiments in greenhouse. In conclusion, B. velezensis BR-01 is a broad-spectrum antagonistic bacterium and has the potential as the ideal biocontrol agent in controlling multiple rice diseases with high efficiency.

Evaluation of the control efficacy of antagonistic bacteria from V-Ti magnetite mine tailings on kiwifruit brown spots in pot and field experiments

“…Bacterial strains with a highly antagonistic effect were cultured in an LB liquid medium, and fresh culture filtrate was collected using disposable filters at 8-h intervals for the Oxford cup experiment (Zhou et al, 2022 ). Two sterilized Oxford cups were placed vertically on culture plates of C. cassiicola ACC10, positioned 3 cm away from the center ( Figure 4B ).…”

The potential of novel bacterial isolates from healthy ginseng for the control of ginseng root rot disease (Fusarium oxysporum)

“…Morphological indicators such as state, color, transparency, and edge were recorded. Gram staining was also performed and observed under a light microscope [ 27 ]. Observe the morphology of antagonistic bacteria and measure the size of the bacteria under scanning electron microscopy (SEM).…”

“…In the parallel confrontation test, fungal colonies (6mm) were collected using a cork borer from the edge of a F. oxysporum culture exhibiting strong growth and placed on a 90mm diameter petri dish containing fresh PDA. The bacterial isolates were then placed on the PDA medium approximately 2cm away from the fungus [27]. The growth of the fungal colony was observed 7d after inoculation of the plates with the bacterial isolates to assess inhibitory activity, relative to fungal growth on plates without bacterial isolates.…”

Characterization of Bacillus velezensis TJS119 and its biocontrol potential against insect pathogens

“…Several strains of B. velezensis have been extensively used in agriculture and biotechnology due to their environmental safety, ease of industrial production, and biocontrol efficacy ( Rabbee et al, 2023 ). These include B. velezensis BR-1 ( Zhou et al, 2022 ), HNA3 ( Zaid et al, 2022 ), GH1-13 ( Kim et al, 2017b ), S3-1 ( Jin et al, 2017 ), M75 ( Kim et al, 2017a ), LS69 ( Liu et al, 2017 ), 9912D ( Pan H. Q. et al, 2017 ), and S499 ( Molinatto et al, 2016 ). However, the relative efficacy of B. velezensis TJS119 against insect pathogens and its mechanism of biocontrol remain unknown.…”