Fusarium Species Associated with Spikes and Grains of Cereal Crops in the Volga Region: Virulence and Toxin-Producing Potential.

Fusarium head blight (FHB) is a major threat to cereal crops, causing yield losses and mycotoxin contamination. This study investigated Fusarium species associated with spikes and grains of cereals in the Volga region, focusing on species diversity, virulence, and mycotoxin production. F. sporotrichioides, F. avenaceum, and F. poae were the most prevalent species isolated from wheat, rye, barley, triticale, and stored grains in the Volga region. Individual strains of F. culmorum and F. graminearum were also identified. High intraspecific variability in virulence was observed for the first time within F. sporotrichioides and F. poae species, and highly virulent strains were identified for the first time within these species. Not only symptomatic but also asymptomatic (weakly expressed) infections caused by F. sporotrichioides were shown to be associated with the accumulation of high levels of T-2 toxin in the grains of infected plants. F. sporotrichioides strains were first demonstrated to exhibit intraspecific variability in zearalenone-producing potential. A F. graminearum strain possessing the nivalenol chemotype was first identified in Russia. The study highlights the diversity of the regional FHB pathocomplex and the risks it poses to grain safety.