Location: Food and Feed Safety Research
Project Number: 6054-41420-009-011-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jun 3, 2024
End Date: Jun 2, 2026
Objective:
Identify and characterize genes and metabolites affecting growth, dissemination, survival, production of government regulated and unregulated mycotoxins, and phytopathogenicity of Aspergillus flavus. In addition to aflatoxins, analyze the production of unregulated toxins in mutant strains to ensure total atoxigenicity. Assess newly identified genes, pathways, and metabolites as possible targets for maize RNAi-based gene silencing approaches. Investigate engineered atoxigenic strains for biocontrol applications.
Approach:
Based on previous studies in other fungi, particularly on the extensive knowledge from the well-established fungal model Aspergillus (A.) nidulans, compelling homolog genes in the aflatoxin-producing plant pathogen A. flavus will be investigated. A. flavus and A. nidulans gene inactivation and overexpression studies will be used to determine the role of previously uncharacterized genes in growth, mycotoxin production, dissemination and virulence in lab media and live maize seeds. Effects of essential metal nutrients (e.g. iron, copper, zinc, manganese) and their role in stimulating or repressing mycotoxin production will be assessed. We will focus on the WOPR transcription factor gene osaA found to be important in other host-pathogen systems. Also, from data acquired from previous A. flavus transcriptomic analysis we will characterize homeobox 1 (hbx1)-dependent genes, such as hdt5. In addition, genes, metal nutrients, and metabolites possibly affecting growth or mycotoxin production, revealed by our recent transcriptomic analysis of a novel Pseudomonas bacterium used as a biocontrol agent against A. flavus, will be characterized. Should any of the identified genes demonstrate a significant role in the biology of the fungus, they can be targets for silencing during infection of maize by the fungus. Additionally, global regulators that affect all toxic A. flavus metabolites will be further investigated for faster identification and development of atoxigenic biocontrol strains.
