Skip to main content
ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #369061

Research Project: Genetic and Environmental Factors Controlling Aflatoxin Biosynthesis

Location: Food and Feed Safety Research

Title: The secondary metabolism of Aspergillus flavus: small molecules with diverse biological function

item Lebar, Matthew
item Cary, Jeffrey
item Carter-Wientjes, Carol
item Mack, Brian
item Majumdar, Raj
item Wei, Qijian - Mei Mei
item UKA, VALDET - Ghent University
item DE SAEGER, SARAH - Ghent University
item DIANA DI MAVUNGU, JOSE - Ghent University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/24/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Aspergillus flavus can colonize important food staples and produce aflatoxins, a group of toxic and carcinogenic secondary metabolites. A. flavus also produces many other secondary metabolites and harbors more than 50 putative secondary metabolite biosynthetic gene clusters that have yet to be characterized. Bioactive secondary metabolites that enhance the ability of the fungus to infect crops are of particular interest. We have recently shown that biosynthetic gene cluster 11 in A. flavus encodes for the biosynthesis of aspergillic acid, a toxic hydroxamic acid-containing pyrazinone compound that can bind iron, resulting in a red-orange pigment known as ferriaspergillin. A decrease in A. flavus pathogenicity and aflatoxin contamination was observed when aspergillic acid biosynthesis was blocked during maize seed infection. We have probed the available genomes of Aspergillus species for biosynthetic gene cluster 11 homologs. We find that all species possessing gene cluster 11 produce aspergillic acid or a closely related isomer. We demonstrate that the Aspergillus section Flavi species harboring biosynthetic gene cluster 11 produce a mixture of aspergillic acid, hydroxyaspergillic acid, and aspergillic acid analogs differing only in the amino acid precursors. Interestingly, many Aspergillus section Circumdati species, known mainly for their production of the problematic mycotoxin ochratoxin A, also harbor gene cluster 11 homologs but do not produce aspergillic acid. Instead, these species produce neoaspergillic acid and its hydroxylated analog neohydroxyaspergillic acid, indicating that cluster 11 is responsible for neoaspergillic acid biosynthesis in Aspergillus section Circumdati.