Ecophysiological behaviour of major Fusarium species in response to combinations of temperature and water activity constraints

ABSTRACT Fusarium Head Blight (FHB) is a devastating fungal disease affecting cereals, caused by Fusarium species that can produce harmful mycotoxins. Fusarium species share the same ecological niche, and their population dynamic and associated mycotoxin patterns are driven by the environment. The aim of the present study was to investigate ecophysiological characteristics of the major Fusarium species causing FHB under abiotic factors. Growth and mycotoxin production of different strains of Fusarium avenaceum, Fusarium graminearum , Fusarium langsethiae, Fusarium poae and Fusarium tricinctum were characterized under a combined effect of temperature (ϴ = 15, 20, 25 and 30°C) and water activity (a w = 0.99, 0.98, 0.97, 0.96, 0.95 and 0.94). Using innovative statistical analyses, we demonstrated that those Fusarium species greatly differ in their responses to the studied environmental constraints. Our findings indicated that ϴ, a w , and their interaction were the major factors with a significant impact on the species behaviour. The intraspecific variation was demonstrated as less pronounced than the interspecific one. Understanding the ecophysiological requirements of Fusarium species is crucial in the context of climate change that is predicted to worsen disease outbreaks. Our data constitute a valuable knowledge base for improving the reliability and robustness of FHB prediction models and anticipating the associated mycotoxin risk. IMPORTANCE Fusarium species pose a significant threat to major cereal crops, including wheat. These fungi not only reduce yield but also produce mycotoxins harmful to animals and humans. The prevalence of each Fusarium species is influenced by environmental conditions and shifts in pathogen populations, leading to changes in mycotoxin patterns have already been observed in relation to climate changes. This study revealed distinct ecophysiological behaviours, including mycelium growth and mycotoxin production, among the five major Fusarium species when exposed to varying temperature and water activity conditions. Our findings provide a valuable foundation for a more comprehensive understanding of the challenge of mycotoxin contamination and for the development of more effective mitigation strategies in the near future.