1887

Abstract

Aflatoxins are polyketide-derived secondary metabolites produced by , , and a few other species. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. Although and , which are used in fermented foods and in ingredient manufacture, have no record of producing aflatoxin, they have been shown to possess an gene. This study examined 34 strains of section . The gene of 23 of these strains was successfully amplified and sequenced. No PCR products were found in five strains or six strains of . These PCR results suggested that the gene is absent or significantly different in some and strains. The sequenced genes from the 23 positive strains had greater than 96·6 % similarity, which was particularly conserved in the zinc-finger DNA-binding domain. The gene of has two obvious characteristics: an extra CTCATG sequence fragment and a C to T transition that causes premature termination of AFLR protein synthesis. Differences between / and / genes were also identified. Some strains of as well as var. , var. and var. have an -type gene. For all strains with the -type gene, there was no evidence of aflatoxin production. It is suggested that for safety reasons, the gene could be examined to assess possible aflatoxin production by section strains.

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2006-01-01
2019-10-17
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