AUTHOR=Zhou Jianping , Xie Yunqiao , Liao Yuhong , Li Xinyang , Li Yiming , Li Shuping , Ma Xiuguo , Lei Shimin , Lin Fei , Jiang Wei , He Yong-Qiang 

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

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.983781

DOI=10.3389/fmicb.2022.983781

ISSN=1664-302X

ABSTRACT=<p>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 <italic>Bolbostemmatis Rhizoma</italic> by plate confrontation method. The strain was identified as <italic>Bacillus velezensis</italic> by morphological observation, physiological and biochemical identification, and molecular characterization by 16S rDNA and <italic>gyrB</italic> gene sequencing analysis. The confrontation test (dual culture) and Oxford cup assays demonstrated that <italic>B. velezensis</italic> BR-01 had strong antagonistic effects on <italic>Magnaporthe oryzae</italic>, <italic>Ustilaginoidea virens</italic>, <italic>Fusarium fujikuroi</italic>, <italic>Xanthomonas oryzae</italic> pv. <italic>Oryzicola</italic>, and <italic>Xanthomonas oryzae</italic> pv. <italic>oryzae</italic>, the major rice pathogens. The genes encoding antimicrobial peptides (<italic>ituA</italic>, <italic>ituD</italic>, <italic>bmyB</italic>, <italic>bmyC</italic>, <italic>srfAA</italic>, <italic>fenB</italic>, <italic>fenD</italic>, <italic>bacA</italic>, and <italic>bacD</italic>) were found in <italic>B. velezensis</italic> BR-01 by PCR amplification with specific primers. <italic>B. velezensis</italic> 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 <italic>B. velezensis</italic> BR-01 had significant control effects on rice bacterial blight and bacterial leaf streak by pot experiments in greenhouse. In conclusion, <italic>B. velezensis</italic> 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.</p>