P-419 - Trichothecene genotype composition of Fusarium graminearum population causing Fusarium head blight in winter wheat in Ohio

Fusarium head blight (caused by the Fusarium graminearum species complex) is an endemic wheat disease in the U.S., causing significant yield and grain quality loss. The disease is concerning due the production of B-trichothecenes mycotoxins by F. graminearum, including deoxynivalenol (DON), nivalenol (NIV), and their acetyl derivatives, 3-acetyl-deoxynivalenol (3-ADON) and 15-acetyl-deoxynivalenol (15-ADON). Monitoring the chemotype profile of F. graminearum populations is important for assessing mycotoxin production risk and understanding the pathogen dynamics over time and space. However, information on the trichothecene genotype composition of F. graminearum infecting winter wheat in Ohio remains limited. During the 2018, 2021 and 2022 growing season, naturally infected wheat spikes were collected across 60 fields distributed across 28 OH counties. In the laboratory, a total of 134 isolates of Fusarium sp. was obtained from symptomatic spikes. Colonies identified as Fusarium spp. based on macroscopic and microscopic characteristics were subcultured on PDA, and pure isolates were obtained using the hyphal tip method. DNA extraction was performed, and isolates were classified into trichothecene groups using multiplex PCR targeting the TRI3 and TRI12 regions. To date, all 115 analyzed isolates have been identified as 15-ADON chemotype. This study is an important step to characterize the trichothecene genotype composition of Fusarium species infecting wheat in Ohio, monitoring shifts in toxin profiles over time and space.