AUTHOR=Cheng Yunqing , Lou Hanxiao , He Hongli , He Xinyi , Wang Zicheng , Gao Xin , Liu Jianfeng 

TITLE=Genomic and biological control of Sclerotinia sclerotiorum using an extracellular extract from Bacillus velezensis 20507

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1385067

DOI=10.3389/fmicb.2024.1385067

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p><italic>Sclerotinia sclerotiorum</italic> is a known pathogen that harms crops and vegetables. Unfortunately, there is a lack of effective biological control measures for this pathogen. <italic>Bacillus velezensis</italic> 20507 has a strong antagonistic effect on <italic>S. Sclerotiorum</italic>; however, the biological basis of its antifungal effect is not fully understood.</p></sec><sec><title>Methods</title><p>In this study, the broad-spectrum antagonistic microorganisms of <italic>B. velezensis</italic> 20507 were investigated, and the active antifungal ingredients in this strain were isolated, purified, identified and thermal stability experiments were carried out to explore its antifungal mechanism.</p></sec><sec><title>Results</title><p>The <italic>B. velezensis</italic> 20507 genome comprised one circular chromosome with a length of 4,043,341 bp, including 3,879 genes, 185 tandem repeats, 87 tRNAs, and 27 rRNAs. Comparative genomic analysis revealed that our sequenced strain had the closest genetic relationship with <italic>Bacillus velezensis</italic> (GenBank ID: NC 009725.2); however, there were significant differences in the positions of genes within the two genomes. It is predicted that <italic>B. velezensis</italic> 20507 encode 12 secondary metabolites, including difficidin, macrolactin H, fengycin, surfactin, bacillibactin, bacillothiazole A-N, butirosin a/b, and bacillaene. Results showed that <italic>B. velezensis</italic> 20507 produced various antagonistic effects on six plant pathogen strains: <italic>Exserohilum turcicum, Pyricularia oryzae, Fusarium graminearum, Sclerotinia sclerotiorum, Fusarium oxysporum</italic>, and <italic>Fusarium verticillioides</italic>. Acid precipitation followed by 80% methanol leaching is an effective method for isolating the antifungal component ME80 in <italic>B. velezensis</italic> 20507, which can damage the membranes of <italic>S. sclerotiorum</italic> hyphae and has good heat resistance. Using high-performance liquid chromatography, and Mass Spectrometry analysis, it is believed that fengycin C72H110N12O20 is the main active antifungal substance.</p></sec><sec><title>Discussion</title><p>This study provides new resources for the biological control of <italic>S. Sclerotiorum</italic> in soybeans and a theoretical basis for further clarification of the mechanism of action of <italic>B. velezensis</italic> 20507.</p></sec>