| Résumé | 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. |
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