Genomic Differences, Mycotoxin Profiles, and Cross-Infectivity Patterns Reveal Host Adaptability of Fusarium graminearum Across Barley, Potato, and Soybean

Fusarium graminearum, the causal agent of Fusarium head blight, contaminates small-grain cereals with deoxynivalenol (DON), threatening food and feed safety. Although widely used to manage the disease, crop rotation is limited by the persistence of F. graminearum in infected crop residues, serving as inoculum for subsequent crops. Here, we generated high-quality genome assemblies for seven F. graminearum isolates from barley, potato, soybean, and winter rye and demonstrated cross-infection across hosts. All isolates shared a large core genome, but accessory gene comparison, genomewide SNP analysis, and mycotoxin profile divided them into two groups: the barley/potato (By/Po), which belong to the NA2 population and are 3-ADON producers, and the soybean/winter rye (Sy/Wr), which belong to NA1 and are 15-ADON producers. Group classification was supported by cross-infectivity data, where By/Po exhibited greater aggressiveness than the Sy/Wr group, particularly for potato inoculations. The correspondence between how the isolates are divided when using source crop, chemotype, aggressiveness, SNP, or accessory gene data suggests that various genetic factors may influence the adaptability of F. graminearum. Our study is the first to demonstrate the connection between cross-infectivity patterns, mycotoxin profile, and genomic variation in Fusarium graminearum.