Location: Food and Feed Safety Research
Title: Testing the efficacy of eGFP-transformed Aspergillus flavus as biocontrol strains Authors
Submitted to: Food and Nutrition Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 22, 2013
Publication Date: April 30, 2013
Citation: Moore, G.G., Mack, B.M., Beltz, S.B. 2013. Testing the efficacy of eGFP-transformed Aspergillus flavus as biocontrol strains. Food and Nutrition Sciences. 4:469-479. Interpretive Summary: A method of pre-harvest biological control against aflatoxigenic fungal contamination in agricultural commodities involves field inoculation with non-aflatoxigenic Aspergillus flavus. Yet to be studied are the long-term impacts of annual applications of these “stable” strains. This manuscript is the initial study to develop a means of tracking the movement and persistence of biocontrol strains that have been tagged with green fluorescent protein. Laboratory investigations included monitoring potential impacts of the GFP on colony growth and fluorescence, followed by homologous and heterologous comparisons of strains to determine any potential impact of GFP on the ability of biocontrol strains to compete against both atoxigenic and toxigenic wild type strains. Overall there is no difference in growth of wild type and transformed strains, and their fluorescence shows promise for future studies using GFP-tagged biocontrol strains.
Technical Abstract: Six non-aflatoxigenic Aspergillus flavus isolates were tagged with enhanced green fluorescent protein. All transformed A. flavus strains exhibit consistent individual growth compared to their wild type parents, though the intensities of their fluorescence were variable. The transformants, as competitors, showed little difference compared to the wild type atoxigenic and toxigenic strains indicating negligible impact of the GFP on their ability to perform as fluorescent biocontrol strains. A biocontrol strain that maintains fluorescence is integral to a time-course study that will monitor their movement and persistence in the field. This manuscript introduces a means to easily track biocontrol strains as a preliminary project for future field trials.