Abstract
Aflatoxins are toxic and carcinogenic secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus. Strains of A. flavus that are non-aflatoxigenic (i.e., incapable of secreting aflatoxins) have proven effective in controlling contamination by these aflatoxin producing species in the field. In the present study, a non-aflatoxigenic A. flavus strain, GD-3, was isolated from a peanut field in Guangdong Province, China. Polymerase chain reaction (PCR) analysis showed that 12 aflatoxin biosynthesis genes (aflT, pksA, nor-1, fas-2, fas-1, aflR, aflJ, adhA, estA, norA, ver-1 and verA) were deleted in GD-3. Co-inoculation with a toxigenic strain, GD-15, at the ratio of 1:10, 1:1 or 10:1 (GD-3:GD-15), showed that GD-3 was capable of reducing detectable aflatoxin levels on three different substrates. This reduction ranged from 33% to 99% and correlated with competitor ratio. These results demonstrated that GD-3 was successful at reducing aflatoxin contamination and showed promise as a potential agent of biocontrol for local farmers.
Acknowledgements
We are grateful to members of the Laboratory of Quality and Biosafety at Institute of Agro-products Processing Science and Technology, Chinese Academy of Agricultural Sciences for comments and participation in discussions.
Disclosure statement
No potential conflict of interest was reported by the authors.