Climate Change: An Inevitable Factor in Reshaping the Contamination Level of Fungi and Mycotoxins

The increasing frequency of extreme weather events, such as heatwaves and heavy rainfall, attributed to climate change, has considerably escalated the multifaceted threat of mycotoxins to agricultural productivity, food security, and public health. This review comprehensively examines the effect of climate change on fungal growth dynamics, mycotoxin production, and exposure patterns. Central to this effect is the phenomenon of niche transition within fungal communities, marked by the expansion of the thermal tolerance of traditional toxigenic species and the emergence of novel thermotolerant fungi via cross-regional migration. In addition, climate change drives the regional migration of mycotoxins and promotes the emergence of "novel" and "masked" mycotoxins by altering substrate effects. Furthermore, climate-driven environmental stress may activate previously silent secondary metabolic gene clusters (or hidden gene clusters) by affecting the regulatory network and epigenetic mechanisms of fungi, thereby reshaping metabolic pathways and inducing differential expression of genes related to toxin synthesis, resulting in a surge in mycotoxin exposure. This review also evaluates current global mycotoxin exposure trends and critically analyzes the limitations of prevailing fungal growth and mycotoxin prediction models, which often fail to explain the nonlinear effects of climate variables. Ultimately, this review underscores the pressing need to redefine the mycotoxin risk framework and develop mechanistic information prediction tools tailored to climate change, thereby warning of new risks associated with global warming.