P-535 - Genetic diversity and population structure of Sarocladium zeae, a protective fungal endophyte for controlling mycotoxins in maize

Monday, August 4, 2025

4:30 PM - 5:15 PM HST

Location: Exhibit Hall 3

Presenting Author(s)

NL

Nino Laurel (he/him/his)

University of Georgia
Athens, Georgia, United States

Author(s)

DO

Drew Olson (he/him/his)

Department of Plant Pathology, University of Georgia
Athens, Georgia, United States
TS

Timothy Satterlee

Toxicology and Mycotoxin Research Unit, USNPRC, USDA-ARS
Athens, Georgia, United States
PS

Paul Severns, PhD

Assistant Professor of Plant Disease Epidemiology
Department of Plant Pathology, University of Georgia
Athens, Georgia, United States
MB

Marin Brewer

Professor of Mycology and William Terrell Distinguished Professor
Department of Plant Pathology, University of Georgia, Athens
Athens, Georgia, United States
RK

Robert C. Kemerait, Jr., PhD

Professor
UGA Dept of Plant Pathology
Tifton, GA, USA
AG

Anthony E. Glenn

Supervisory Plant Pathologist (Research Leader)
Toxicology and Mycotoxin Research Unit, USNPRC, USDA-ARS
Athens, Georgia, United States

Abstract Text: Sarocladium zeae is a protective fungal endophyte that co-inhabits maize kernels with the mycotoxigenic pathogen Fusarium verticillioides. This fungus produces pyrrocidines, which suppress fumonisin biosynthesis in F. verticillioides, highlighting its potential as a biological control agent in controlling mycotoxin contamination in maize. To explore the genetic diversity and population structure of S. zeae isolated from Georgia-grown maize, we analyzed whole genome sequences of 98 isolates using population genomics and phylogenomics. Reference-based genome mapping identified 832,302 high-quality single nucleotide polymorphisms, which were reduced to 32,776 after linkage pruning. Bayesian analysis (STRUCTURE) and principal coordinates analysis revealed that there are two genetically distinct S. zeae populations: ‘Pop1’ (87 isolates), widely distributed across 11 counties in Georgia, and ‘Pop2’ (11 isolates), exclusively found in Irwin County. Phylogenomic analysis suggested a predominantly clonal population structure, with potential local adaptation or limited dispersal as evidenced by geographic clustering. Hierarchical F_ST analysis confirmed significant genetic differentiation between the two populations (F_ST = 0.1863). Together, this study represents the first in-depth genomic analysis of S. zeae in Georgia. Moving forward, we aim to characterize the morphology and pyrrocidine production of these isolates, correlate these traits with genomic data, and identify pyrrocidine super-producing strains for potential use as a biological control agent against mycotoxigenic fungi.