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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #361781

Research Project: Genetic and Environmental Factors Controlling Aflatoxin Biosynthesis

Location: Food and Feed Safety Research

Title: Aspergillus flavus secondary metabolites and their roles in fungal development, survival and virulence

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

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/6/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Aspergillus flavus is primarily known for its ability to produce toxic and carcinogenic aflatoxins during colonization of susceptible crops such as maize and groundnut. A total of 56 secondary metabolite (SM) gene clusters are predicted to be present in the A. flavus genome. To date, metabolites have only been experimentally assigned to thirteen of these SM clusters. It is important to identify as many of these compounds as possible to determine their bioactivity with respect to fungal development, survival, and virulence. We have identified and functionally characterized metabolites associated with a number of previously uncharacterized SM clusters including those involved in fungal development and survival (asparasone A and leporins). We recently identified aspergillic acid (AA) as the product of a nonribosomal peptide synthetase (NRPS) present in SM cluster #11. The hydroxamic acid functional group in both aspergillic acid and its hydroxy-analog allows the molecules to bind to iron resulting in the production of a red pigment in A. flavus identified as ferriaspergillin. Knockout of the NRPS gene resulted in loss of AA production. An A. flavus NRPS mutant demonstrated significantly reduced levels of infection and growth in a laboratory assay with corn kernels resulting in reduction of aflatoxin B1 and cyclopiazonic acid compared to a control. This suggests a role for AA in iron homeostasis and virulence on crops.