Changing Patterns of Fungal Toxins in Crops: Challenges for Analysts

This short review discusses the need to manage climate-driven expansion of old toxins in new geographic areas (e.g., aflatoxin or fumonisin in corn in historically cooler areas, and ergot where rainfall and cropping patterns have changed). In addition, a renewed consideration of the toxins that can occur in feed sources used in cool-season dairy areas is needed (e.g., silage and distillers dry grains with solubles). A separate issue concerns genetic changes that are occurring in the species that cause Fusarium head blight/Gibberella ear rot. Small differences in climate appear to determine the distribution of the two dominant populations (native to the new world and from Asia). The chemotype that produces deoxynivalenol via the monoacetate at the 3 position results in the accumulation of somewhat more deoxynivalenol than the native population, which involves the monoacetate at the 15 position. There are also genetic changes occurring that have resulted in populations that produce different metabolites. Similarly, an increase in the area where Aspergillus flavus can thrive and the discovery of the sexual stage of this fungus have raised the potential of genetic change accelerated by climate. To address all these issues, new methods and increased availability of reference standards, as well as training and awareness, will be required.