P-262 - Identification of Potential Fungicide Resistance Markers Using Genome-Wide Association Studies in Aspergillus flavus

Tuesday, August 5, 2025

9:30 AM - 10:15 AM HST

Location: Exhibit Hall 3

Presenting Author(s)

EJ

Emil Joson (he/him/his)

Graduate Research Assistant
University of Georgia
Griffin, Georgia, United States

Author(s)

AA

Alison Adams (she/her/hers)

Postdoctoral Research Associate
University of Georgia
Griffin, GA, USA
JC

Josh Clevenger

Faculty Investigator
HudsonAlpha
Huntsville, Alabama, United States
ZM

Zack Myers

Computational Biologist
HudsonAlpha
Huntsville, Alabama, United States
WK

Walid Korani

Research Faculty Investigator
HudsonAlpha
Huntsville, Alabama, United States
MA

Md. Aktaruzzaman, PhD

Postdoctoral Research Associate
University of Georgia
Tifton, Georgia, United States
TB

Timothy B. Brenneman, PhD

Professor
University of Georgia
Tifton, Georgia, United States
JF

Jake Fountain

Assistant Professor Mycotoxicology & Postharvest Pathology
University of Georgia
Griffin, Georgia, United States

Abstract Text: Population genomics is a powerful tool for investigating genetic diversity of fungi across a broad area. Our group is using this approach to survey the population of Aspergillus flavus from peanut production environments in Georgia. As a subset of this larger 1,000 A. flavus Genome Initiative, 78 whole genomes were sequenced from A. flavus isolated from 2020 seed lots where resistance to QoI fungicides was reported. Variant calling and filtering were done against the A. flavus AF13 reference (GCA_014117485.1) using GATK and Plink resulting in a total of 14,692 single nucleotide polymorphisms (SNPs) from the nuclear genome. Mitochondrial genomic variants were identified against A. flavus NRRL3357 (JQ355000.1) resulting in 24 SNPs. Given emerging resistance against QoI fungicides has been attributed to cytochrome B mutations, examining the SNPs revealed 9 (11.5%) isolates with F129L and 22 (28.2%) with G143A. Initial population analysis using STRUCTURE revealed two distinct populations with strains harboring cytochrome B mutations all belonging to the same cluster. Pairing the SNPs with sensitivity data for common seed treatment fungicides (prothioconazole, fludioxonil, thiabendazole, and fluopyram), genome-wide association studies (GWAS) identified SNPs significantly associated with fludioxonil and prothioconazole resistance within genes involved in amino acid transport and G-protein signaling. These markers may prove useful in screening the larger collection and predict the potential distribution of fungicide resistance in A. flavus and inform extension recommendations.