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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #356374

Research Project: Molecular and Environmental Factors Controlling Aflatoxin Reduction by Non-Toxigenic Aspergillus Strains

Location: Food and Feed Safety Research

Title: The role of extrolites secreted by nonaflatoxigenic Aspergillus flavus in biocontrol efficacy

item Moore, Geromy
item Lebar, Matthew
item Carter-Wientjes, Carol

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2018
Publication Date: 12/13/2018
Citation: Moore, G.G., Lebar, M.D., Carter-Wientjes, C.H. 2018. The role of extrolites secreted by nonaflatoxigenic Aspergillus flavus in biocontrol efficacy. Journal of Applied Microbiology. 126:1257-1264.

Interpretive Summary: Field control of aflatoxin contamination is thought to occur through competitive exclusion of native aflatoxigenic fungi by Aspergillus flavus biocontrol strains. In this study, we explored another possible mechanism that could increase the efficacy of biocontrol strains-- the production of secreted compounds (i.e. extrolites). Our finding, that extrolites secreted by non-aflatoxigenic A. flavus strains potentially abate growth and toxin levels of aflatoxin-producing strains, should allow for us to elucidate the mechanism of how the reduction of toxigenic strains occurs, and potentially identify better biocontrol strains. Identification and isolation of the active extrolites may afford a supplemental method to mitigate aflatoxin production.

Technical Abstract: Using four Aspergillus strains (one non-aflatoxigenic and three aflatoxigenic) from the same geographic region (Louisiana), we devised experiments whereby each aflatoxigenic strain was grown on media that had first been colonized by the non-aflatoxigenic strain. We observed noticeable reduction in growth and reduced production of aflatoxin and cyclopiazonic acid for all three aflatoxigenic strains when grown in the presence of extrolite secretions from the non-aflatoxigenic strain. We provide evidence that biocontrol strain extrolites may improve their efficacy at pre- and post-harvest aflatoxin reduction.