Elevated CO₂ induces cultivar-dependent changes in wheat proteins linked to wheat-related disorders and baking quality.

Rising atmospheric CO₂ concentrations may alter the protein composition of wheat and thereby affect grain quality. Ten wheat cultivars were treated with elevated CO2 concentration (eCO2, 546 ppm) and compared to ambient CO2 concentration (aCO2, 450 ppm) in the field to assess changes in amylase/trypsin-inhibitors (ATI), puroindolins (PIN), and gluten proteins using targeted LC-MS/MS and stable isotope dilution analysis. ATI content was higher under eCO2 than under aCO2, whereas PIN, gluten proteins, and selected celiac disease-active peptides were lower. The response to eCO2 was strongly genotype-dependant. The lower gluten protein content under eCO2 was associated with reduced baking quality. While the observed changes in ATI and selected celiac disease-active peptides may be relevant for wheat-related disorders, their biological and immunological significance remains to be established. The findings highlight the importance of identifying cultivars with low levels of ATI and celiac disease-active peptides while maintaining good baking quality under rising CO2.