Title: | Inhibition of Fungal Growth and Induction of a Novel Volatilome in Response to Chromobacterium vaccinii Volatile Organic Compounds |
Author(s): | Ebadzadsahrai G; Higgins Keppler EA; Soby SD; Bean HD; |
Address: | "College of Science, Engineering and Technology, Grand Canyon University, Phoenix, AZ, United States. School of Life Sciences, Arizona State University, Tempe, AZ, United States. Center for Fundamental and Applied Microbiomics, The Biodesign Institute, Tempe, AZ, United States. Biomedical Sciences Program, College of Graduate Studies, Midwestern University, Glendale, AZ, United States. College of Veterinary Medicine, Midwestern University, Glendale, AZ, United States" |
ISSN/ISBN: | 1664-302X (Print) 1664-302X (Electronic) 1664-302X (Linking) |
Abstract: | "The study of chemical bioactivity in the rhizosphere has recently broadened to include microbial metabolites, and their roles in niche construction and competition via growth promotion, growth inhibition, and toxicity. Several prior studies have identified bacteria that produce volatile organic compounds (VOCs) with antifungal activities, indicating their potential use as biocontrol organisms to suppress phytopathogenic fungi and reduce agricultural losses. We sought to expand the roster of soil bacteria with known antifungal VOCs by testing bacterial isolates from wild and cultivated cranberry bog soils for VOCs that inhibit the growth of four common fungal and oomycete plant pathogens, and Trichoderma sp. Twenty one of the screened isolates inhibited the growth of at least one fungus by the production of VOCs, and isolates of Chromobacterium vaccinii had broad antifungal VOC activity, with growth inhibition over 90% for some fungi. Fungi exposed to C. vaccinii VOCs had extensive morphological abnormalities such as swollen hyphal cells, vacuolar depositions, and cell wall alterations. Quorum-insensitive cviR (-) mutants of C. vaccinii were significantly less fungistatic, indicating a role for quorum regulation in the production of antifungal VOCs. We collected and characterized VOCs from co-cultivation assays of Phoma sp. exposed to wild-type C. vaccinii MWU328, and its cviR (-) mutant using stir bar sorptive extraction and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (SBSE-GC x GC-TOFMS). We detected 53 VOCs that differ significantly in abundance between microbial cultures and media controls, including four candidate quorum-regulated fungistatic VOCs produced by C. vaccinii. Importantly, the metabolomes of the bacterial-fungal co-cultures were not the sum of the monoculture VOCs, an emergent property of their VOC-mediated interactions. These data suggest semiochemical feedback loops between microbes that have co-evolved for sensing and responding to exogenous VOCs" |
Keywords: | emergent properties fungal pathogen antagonism inter-kingdom communication quorum sensing (QS) semiochemical communication volatile organic compound (VOC); |
Notes: | "PubMed-not-MEDLINEEbadzadsahrai, Ghazal Higgins Keppler, Emily A Soby, Scott D Bean, Heather D eng Switzerland 2020/06/09 Front Microbiol. 2020 May 20; 11:1035. doi: 10.3389/fmicb.2020.01035. eCollection 2020" |