| Title | Isolation and characterization of Aspergillus flavus strains in China |
|---|---|
| Author | Firew Tafesse Mamo1,2, Bo Shang3, Jonathan Nimal Selvaraj4, Yan Wang1,2, and Yang Liu1,2* |
| Address | 1Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. China, 2Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing 100193, P. R. China, 3Academy of State Administration of Grain, Beijing 100037, P. R. China, 4The College of Life Sciences, Hubei University, Wuhan, 430062, P. R. China |
| Bibliography | Journal of Microbiology, 56(2),119–127, 2018, |
| DOI | 10.1007/s12275-018-7144-1 |
| Key Words | aflatoxin, Aspergillus flavus, atoxigenic strain, cyclopiazonic acid (CPA), toxigenic strains, biocontrol |
| Abstract | Important staple foods (peanuts, maize and rice) are susceptible to contamination by aflatoxin (AF)-producing fungi such as Aspergillus flavus. The objective of this study was to explore non-aflatoxin-producing (atoxigenic) A. flavus strains as biocontrol agents for the control of AFs. In the current study, a total of 724 A. flavus strains were isolated from different regions of China. Polyphasic approaches were utilized for species identification. Non-aflatoxin and non-cyclopiazonic acid (CPA)-producing strains were further screened for aflatoxin B1 (AFB1) biosynthesis pathway gene clusters using a PCR assay. Strains lacking an amplicon for the regulatory gene aflR were then analyzed for the presence of the other 28 biosynthetic genes. Only 229 (32%) of the A. flavus strains were found to be atoxigenic. Smaller (S) sclerotial phenotypes were dominant (51%) compared to large (L, 34%) and non-sclerotial (NS, 15%) phenotypes. Among the atoxigenic strains, 24 strains were PCR-negative for the fas-1 and aflJ genes. Sixteen (67%) atoxigenic A. flavus strains were PCRnegative for 10 or more of the biosynthetic genes. Altogether, 18 new PCR product patterns were observed, indicating great diversity in the AFB1 biosynthesis pathway. The current study demonstrates that many atoxigenic A. flavus strains can be isolated from different regions of China. In the future laboratory as well as field based studies are recommended to test these atoxigenic strains as biocontrol agents for aflatoxin contamination. |