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

• Published in: Biocontrol science and technology Vol. 25; no. 5; pp. 583 - 592
• Main Authors: Zhou, Lu, Wei, Dan-Dan, Selvaraj, Jonathan Nimal, Shang, Bo, Zhang, Chu-Shu, Xing, Fu-Guo, Zhao, Yue-Ju, Wang, Yan, Liu, Yang
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 2015
• Subjects: aflatoxins; Aspergillus flavus; Aspergillus parasiticus; biological control; biological control agents; biosynthesis; carcinogenicity; farmers; genes; peanuts; polymerase chain reaction; secondary metabolites; toxigenic strains; China
• ISSN: 1360-0478

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.