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A strain of Aspergillus flavus from China shows potential as a biocontrol agent for aflatoxin contamination

Zhou, Lu, Wei, Dan-Dan, Selvaraj, Jonathan Nimal, Shang, Bo, Zhang, Chu-Shu, Xing, Fu-Guo, Zhao, Yue-Ju, Wang, Yan, Liu, Yang
Biocontrol science and technology 2015 v.25 no.5 pp. 583-592
Aspergillus flavus, Aspergillus parasiticus, aflatoxins, biological control, biological control agents, biosynthesis, carcinogenicity, farmers, genes, peanuts, polymerase chain reaction, secondary metabolites, toxigenic strains, China
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.