12 June 2014

3 minute read

Paula Kovalsky, PhD

In mid-May, the scary El Niño forecast for this summer was all over the news: Shuhei Maeda from the Japan Meteorological Agency predicts a high likelihood for an El Niño weather cycle to be the strongest since a record in 1997/98, with consequences on maize, rice and wheat yields.

Global warming might intensify the storms and floods associated with El Niño, scientists from NOAA already pointed out in 1998.

Is climate change impacting current fungal profiles?

The occurrence of mycotoxins is a worldwide phenomenon that affects all kinds of commodities. The conditions under which these toxic substances are produced depend highly on two main factors: water availability and temperature that affect the life cycle of mycotoxigenic fungi.

It seems that we are facing shifts in mycotoxin patterns as the world is experiencing climate changes. This much-discussed topic does not only imply temperature increase, but also increases in carbon dioxide levels and high variability in weather conditions, including changes in precipitation patterns and frequent storms.

The Intergovernmental Panel on Climate Change (IPCC) report of 2014 shows different global warming projections, with a prediction that in the year 2100, global temperatures may increase by up to 4.8°C.

Climate change is expected to affect agriculture not only due to the physiological response of crops to temperature increase, changes in precipitation patterns and atmospheric carbon dioxide concentrations, but also due to other factors. On the one hand, changes in temperature and water availability may influence the efficacy of fungicide and pesticide pre-harvest applications. On the other hand, climate change may alter the geographical distribution or the life-cycle of insects that promote fungal infections of crops.

We are also observing how some fungal species are being displaced by other more virulent or aggressive fungi.

According to the 2008 FAO report on climate change and its implications on food safety, Fusarium culmorum is being replaced by Fusarium graminearum, the most virulent plant pathogen. In North America, here are changes being observed in Fusarium populations to more toxigenic Fusarium isolates.

Novel strains are also being discovered that form unexpected toxins, which may be the result of a changing environment. For instance in Minnesota, a novel Fusarium isolate called the 'Northland population' has emerged, which does not produce the protein synthesis inhibiting trichothecenes deoxynivalenol or nivalenol.

It is assumed that the highest mycotoxin risks will be observed not only in countries with tropical climates but also in countries with temperate climates, such as parts of Europe and the United States of America, if temperature begins to rise and favors aflatoxin B1 production.

During the hot and dry episodes in northern Italy in 2003, Aspergillus flavus was able to colonise the ripening maize, a key crop, by outcompeting the more common Fusarium species. This led to an uncommon increase in aflatoxin B1 contamination in Europe.

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