Isolation and Study on the Aflatoxin Genes of Aflatoxin-producing Fungi in Paprika Samples in Chengdu

Objective To isolate aflatoxin-producing strains from paprika samples and to do a preliminarily study on the relationship between aflatoxin-producing ability and the genes aflR, omt-1and ver-1 Methods Fungi were isolated by traditional culture method. Potential aflatoxin-producing strains were screened by phenotypic traits and multiplex PCR. After these potential aflatoxin-producing strains cultured in the toxigenic culture medium, the levels of aflatoxin B1 (AFB1) of the cultures were tested with ELISA method. The phylogenetic tree of aflR, omt-1and ver-1 was constructed to explore the relationship between these genes and the AFB1-producing capacity. Results 17 potential aflatoxin-producing fungi were isolated. The ratio of positive toxigenic strains is 64.71%. 11 isolates were positive in AFB1 detection while existing high sequence homology with AS 3.4408, 6 isolates were negative in AFB1 detection while existing high sequence homology with Aspergillus oryzae. Conclusion Aspergillus flavusare potential candidates for aflatoxin control. Not all Aspergillus flavus have AFB1-producing capacity, AflR gene had a direct relation to AFB1-producing capacity, while ver-1 and omt-1were related to the level of AFB1 producing.