Rising atmospheric CO 2 concentration may imply higher risk of Fusarium mycotoxin contamination of wheat grains

Abstract

Increasing atmospheric CO₂ concentration not only has a direct impact on plants but also affects plant–pathogen interactions. Due to economic and health-related problems, special concern was given thus in the present work to the effect of elevated CO₂ (750 μmol mol⁻¹) level on the Fusarium culmorum infection and mycotoxin contamination of wheat. Despite the fact that disease severity was found to be not or little affected by elevated CO₂ in most varieties, as the spread of Fusarium increased only in one variety, spike grain number and/or grain weight decreased significantly at elevated CO₂ in all the varieties, indicating that Fusarium infection generally had a more dramatic impact on the grain yield at elevated CO₂ than at the ambient level. Likewise, grain deoxynivalenol (DON) content was usually considerably higher at elevated CO₂ than at the ambient level in the single-floret inoculation treatment, suggesting that the toxin content is not in direct relation to the level of Fusarium infection. In the whole-spike inoculation, DON production did not change, decreased or increased depending on the variety × experiment interaction. Cooler (18 °C) conditions delayed rachis penetration while 20 °C maximum temperature caused striking increases in the mycotoxin contents, resulting in extremely high DON values and also in a dramatic triggering of the grain zearalenone contamination at elevated CO₂. The results indicate that future environmental conditions, such as rising CO₂ levels, may increase the threat of grain mycotoxin contamination.

http://ift.tt/2rpOP79