Effects of atmospheric CO2 level on the metabolic response of resistant and susceptible wheat to Fusarium graminearum infection

Authors: CUPERLOVIC-CULF, MIROSLAVA - National Research Council - Canada; Vaughan, Martha; Vermillion, Karl; SURENDRA, ANU - National Research Council - Canada; Teresi, Jennifer; McCormick, Susan

Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2018
Publication Date: 9/26/2018
Citation: Cuperlovic-Culf, M., Vaughan, M., Vermillion, K., Surendra, A., Teresi, J., McCormick, S. 2018. Effects of atmospheric CO2 level on the metabolic response of resistant and susceptible wheat to Fusarium graminearum infection. Molecular Plant-Microbe Interactions. https://doi.org/10.1094/MPMI-06-18-0161-R.
DOI: https://doi.org/10.1094/MPMI-06-18-0161-R

Interpretive Summary: Fusarium head blight (FHB) is one of the most devastating diseases of wheat caused primarily by the fungal pathogen, Fusarium graminearum (Fg). Infection reduces yield and can contaminate grain with harmful mycotoxins. FHB outbreaks are strongly associated with weather, and rising atmospheric carbon dioxide (CO2) concentrations and associated weather extremes are predicted to increase the risk of wheat disease and grain mycotoxin contamination. In order to test this hypothesis, ARS scientists with the Mycotoxin Prevention and Applied Microbiology Unit, Peoria, IL, in collaboration with scientists at the National Research Council Canada, Ontario, CA, assessed the impact of elevated CO2 on the defense response of spring wheat varieties against Fg isolates. At elevated CO2 the moderately resistant wheat variety was more susceptible to fungal invasion and mycotoxin accumulation by one Fg isolate, but not the other. However, the susceptible variety showed enhanced resistance to fungal invasion but no difference in mycotoxin contamination. These results indicate that variation among different fungal strains and wheat cultivars must be considered when evaluating the influence of climatic changes on FHB and mycotoxin contamination. However, metabolite profiling revealed that elevated CO2 changes the production of several disease resistance related metabolites in the wheat cultivars tested. Additionally, we have identified a set of metabolites that can be reliably used by breeders to select for FHB resistance even as atmospheric CO2 levels rise.

Technical Abstract: Rising atmospheric CO2 concentration and associated climate changes are thought to have contributed to the steady increase of Fusarium head blight (FHB) on wheat. However, our understanding of precisely how elevated CO2 influences the defense response of wheat against Fusarium graminearum (Fg) remains limited. In this study, we evaluated the metabolic profiles of susceptible (Norm) and moderately resistant (Alsen) spring wheat in response to whole-head inoculation with two deoxynivalenol (DON) producing Fg isolates (DON+) Fg isolates (9F1 and Gz3639), and a DON deficient (DON-) Fg isolate (Gzt40) at ambient (400ppm) and elevated (800ppm) CO2 concentrations. The effects of elevated CO2 were dependent on both the Fg strain and the wheat variety, but metabolic differences in the host can explain the observed changes in Fg biomass and DON accumulation. The complexity of abiotic and biotic stress interactions make it difficult to determine if the observed metabolic changes in wheat are a result of CO2 induced changes in the host, the pathogen, or a combination of both. However, the effects of elevated CO2 were not dependent on DON production. Finally, we identified several metabolic biomarkers for wheat that can reliably predict FHB resistance or susceptibility even as atmospheric CO2 levels rise.