Rapid identification of Fusarium species causing head blight in Canada using MALDI-TOF mass spectrometry

Fusarium head blight is a limitation to grain production and can be caused by several different Fusarium species. We evaluated the ability of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) to perform species identifications. The method generates a unique peptide mass fingerprint (PMF) for each sample that can be matched to a reference library. We first created a reference library of PMF profiles for Fusarium species from across Canada. Then, we tested the library to perform identifications using two validation panels. The first panel consisted of 820 fungal isolates from wheat (2021-2023 harvest years) and the second was 74 fungal isolates from oat and barley (2022 harvest year). The species identity of samples from the validation panels was confirmed with high-throughput quantitative PCR using species-specific DNA markers. The first validation panel was mostly F. graminearum and there was 95% overlap between the MALDI-TOF MS and DNA-based identifications. The second panel was mostly F. poae and the identifications from the two methods had 86% overlap. Our findings indicate that MALDI-TOF MS biotyping is sensitive enough to identify Fusarium strains to their species complexes and certain Fusarium strains to the species level.