A Bacillus velezensis strain shows antimicrobial activity against soilborne and foliar fungi and oomycetes
Date
2024-02-23
Journal Title
Journal ISSN
Volume Title
Publisher
Frontiers in Fungal Biology
Abstract
Biological control uses naturally occurring antagonists such as bacteria or fungi for environmentally friendly control of plant pathogens. Bacillus spp. have been used for biocontrol of numerous plant and insect pests and are well-known to synthesize a variety of bioactive secondary metabolites. We hypothesized that bacteria isolated from agricultural soil would be effective antagonists of soilborne fungal pathogens. Here, we show that the Delaware soil isolate Bacillus velezensis strain S4 has in vitro activity against soilborne and foliar plant pathogenic fungi, including two with a large host range, and one oomycete. Further, this strain shows putative protease and cellulase activity, consistent with our prior finding that the genome of this organism is highly enriched in antifungal and antimicrobial biosynthetic gene clusters. We demonstrate that this bacterium causes changes to the fungal and oomycete hyphae at the inhibition zone, with some of the hyphae forming bubble-like structures and irregular branching. We tested strain S4 against Magnaporthe oryzae spores, which typically form germ tubes and penetration structures called appressoria, on the surface of the leaf. Our results suggest that after 12 hours of incubation with the bacterium, fungal spores form germ tubes, but instead of producing appressoria, they appear to form rounded, bubble-like structures. Future work will investigate whether a single antifungal molecule induces all these effects, or if they are the result of a combination of bacterially produced antimicrobials.
Description
This article was originally published in Frontiers in Fungal Biology. The version of record is available at: https://doi.org/10.3389/ffunb.2024.1332755. © 2024 Wockenfuss, Chan, Cooper, Chaya, Mauriello, Yannarell, Maresca and Donofrio. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)(http://creativecommons.org/licenses/by/4.0/). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Keywords
biocontrol agent, antifungals, Magnaporthe oryzae, appressorial formation, plant pathogens, hyphae
Citation
Wockenfuss A, Chan K, Cooper JG, Chaya T, Mauriello MA, Yannarell SM, Maresca JA and Donofrio NM (2024) A Bacillus velezensis strain shows antimicrobial activity against soilborne and foliar fungi and oomycetes. Front. Fungal Biol. 5:1332755. doi: 10.3389/ffunb.2024.1332755