Effects of atmospheric CO2 and temperature on wheat and corn susceptibility to Fusarium graminearum and deoxynivalenol contamination

Authors: Hay, William; McCormick, Susan; Vaughan, Martha

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2021
Publication Date: 11/25/2021
Citation: Hay, W.T., McCormick, S.P., Vaughan, M.M. 2021. Effects of atmospheric CO2 and temperature on wheat and corn susceptibility to Fusarium graminearum and deoxynivalenol contamination. Plants. 10(12). Article 2582. https://doi.org/10.3390/plants10122582.
DOI: https://doi.org/10.3390/plants10122582

Interpretive Summary: The fungus Fusarium graminearum infects cereal crops and contaminates grain with dangerous mycotoxins which make it unsafe to eat. Fusarium disease can cause billions of dollars in annual losses to farmers and grain processors. The severity of the disease epidemics is strongly associated with weather, but it wasn’t known how specific changes in carbon dioxide and temperature would impact Fusarium graminearum disease or mycotoxin contamination. Increased carbon dioxide in the atmosphere is associated with increases in temperature. ARS researchers at Peoria, Illinois, studied how changes in temperature and carbon dioxide in the atmosphere could affect Fusarium disease and mycotoxin contamination in wheat and corn, and they found that both crops were more susceptible to disease when grown at higher levels of carbon dioxide. Warmer temperatures also caused more disease in wheat. However, warmer temperatures decreased the amount of mycotoxin contamination in both corn and wheat. This study is important for understanding the potential impact of global climate change on future food security.

Technical Abstract: This work details the impact of atmospheric CO2 and temperature conditions on two strains of Fusarium graminearum, their disease damage, pathogen growth, mycotoxin accumulation and production per unit fungal biomass in wheat and corn. Elevated atmospheric CO2 concentration, 1000 ppm CO2, significantly increased the accumulation of deoxynivalenol in infected plants. Furthermore, growth in cool growing conditions, 20 °C/ 18 °C, day and night, respectively, resulted in the highest amounts of pathogen biomass and toxin accumulation in both inoculated wheat and corn. Warm temperatures, 25 °C/23 °C, day and night, respectively, suppressed pathogen growth and toxin accumulation, with reductions as great as 99% in corn. In wheat, despite reduced pathogen biomass and toxin accumulation at warm temperatures, the fungal pathogen was more aggressive with greater disease damage and toxin production per unit biomass. Disease outcome was also pathogen strain specific, with complex interactions between host, strain, and growth conditions. However, we found that atmospheric CO2 and temperature had essentially no significant interactions, except for greatly increased deoxynivalenol accumulation in corn at cool temperatures and elevated CO2. Plants were most susceptible to disease damage at warm and cold temperatures for wheat and corn, respectively. This work helps elucidate the complex interaction between abiotic stresses and biotic susceptibility of wheat and corn to Fusarium graminearum infection to better understand the potential impact global climate change poses to future food security.