Although aflatoxin biosynthesis has been documented for Aspergillus flavus and A. parasiticus, the closely related species A. oryzae and A. sojae which are widely used in food and ingredient manufacture have no history of producing aflatoxins. Despite this lack of aflatoxin production, several groups have reported the presence of genes associated with aflatoxin biosynthesis, including the pathway-specific regulatory gene aft, in strains of A. oryzae and A. sojae. We confirm by sequencing the presence of 3 structural genes (nor-1, ver-I and omtA) and the regulatory gene, aflR, in strains of A. oryzae and A. sojae. We also report the sequence of the entire aflR gene from A. oryzae ATCC 14895. Northern blot and RT-PCR analysis show that none of these genes are actively transcribed in the chosen strains of A. sojaelA. oryzae. Sequence analysis reveals that the AFLR proteins are truncated by ca. 60 as in all the A. sojae strains examined, a mutation that appears to be linked to a small duplication at the N-terminal end of the protein.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)