isolate of Aspergillus flavus used to reduce aflatoxin contamination in cottonseed has a defective polyketide synthase gene

• Published in: Applied microbiology and biotechnology Vol. 65; no. 4; pp. 473 - 478
• Main Authors: Ehrlich, K.C, Cotty, P.J
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01-09-2004; Springer Nature B.V
• Subjects: Aflatoxins; Aflatoxins - biosynthesis; Aflatoxins - genetics; Agricultural land; Amino Acid Sequence; Aspergillus flavus; Aspergillus flavus - enzymology; Aspergillus flavus - genetics; Base Sequence; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biosynthesis; Biotechnology; Codon, Nonsense; contaminants; Contamination; Cottonseed Oil; DNA, Fungal - chemistry; feed contamination; Food Contamination; Fundamental and applied biological sciences. Psychology; Fungi; Gene Expression; Genes, Fungal; Isolation and description; Mission oriented research; Molecular Sequence Data; Mycotoxins; nontoxigenic strains; Polyketide Synthases - genetics; Polymorphism, Single Nucleotide; RNA, Fungal - analysis; RNA, Messenger - analysis; Sequence Analysis, DNA; Competition; Aspergillus flavus; Mycotoxin; Fungi; Toxin; Gene; Isolate; Fungi Imperfecti; Mutation; Biological contamination; Aflatoxin; Thallophyta; Polymorphism
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-004-1670-y

Contamination of certain foods and feeds with the highly toxic and carcinogenic family of Aspergillus mycotoxins, the aflatoxins, can place a severe economic burden on farmers. As one strategy to reduce aflatoxin contamination, the non-aflatoxin-producing A. flavus isolate AF36 is currently being applied to agricultural fields to competitively exclude aflatoxin-producing Aspergillus species. We now show that the polyketide synthase gene (pksA) required for aflatoxin biosynthesis in AF36, and in other members of the same vegetative compatibility group, possesses a nucleotide polymorphism near the beginning of the coding sequence. This nucleotide change introduces a premature stop codon into the coding sequence, thereby preventing enzyme production and aflatoxin accumulation.