Screening mycotoxins for quorum inhibition in a biocontrol bacterial endophyte

Authors: Mitchell, Trevor; Hinton, Dorothy; Bacon, Charles

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 5/17/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Bacterial endophytes are used as biocontrol organisms for plant pathogens such as the maize endophyte Fusarium verticillioides and its production of fumonisin mycotoxins. However, such applications are not always predictable and efficient. Bacteria communicate via cell-dependent signals, which are referred to as quorum sensing resulting from the production of metabolites that regulate a cascade of gene expressions resulting in biocontrol activity. The assumed role for mycotoxins is to act as defensive metabolites thus serving as protection for fungi from biotic antagonisms and as such do not interact with the daily metabolic requirements of the producing fungus. Recently, quorum-sensing inhibitors have been isolated from several fungi, including Fusarium species, three of which are mycotoxins. Thus, we postulate that other mycotoxins are also inhibitors of quenching metabolites aimed at preventing key biochemical activities of biocontrol bacteria within intercellular spaces. Biosensor bacteria have been developed as useful assays for both quorum sensing and inhibitory activities. In order to test this hypothesis, we determined the quorum inhibitory activity of some common mycotoxins using two strains of biosensor bacteria, Chromobacterium violaceum, and Agrobacterium tumefaciens to access their role in inhibiting developmental controls of the bacterium endophyte Bacillus mojavensis.