Rising CO2 concentration altered wheat grain proteome and flour rheological characteristics

• Wheat (cv. H45) was grown at elevated CO2 (e[CO2], ∼550 μmol CO2 mol−1).
• Grain proteomic analysis was performed, flour rheological properties were analysed.
• Differentially expressed proteins of >1.5-fold over control treatment identified.
• Grain protein and flour rheological properties were altered at e[CO2].
• Changes of grain proteome at e[CO2] closely associated with inferior rheological properties.

Wheat cv. H45 was grown under ambient CO2 concentration and Free Air CO2 Enrichment (FACE; e[CO2], ∼550 μmol CO2 mol−1). The effect of FACE on wheat grain proteome and associated changes in the flour rheological properties was investigated. A comparative proteomic analysis was performed using 2-D-DIGE followed by MALDI/TOF-MS. Total grain protein concentration was decreased by 9% at e[CO2]. Relative abundance of three high molecular weight glutenin sub units (HMW-GS) were decreased at e[CO2]. In contrast, relative abundance of serpins Z1C and 1-Cys peroxiredoxin was increased at e[CO2]. Elevated [CO2] also decreased the bread volume (by 11%) and dough strength (by 7%) while increased mixing time. However, dough extensibility and dough stability were unchanged at elevated [CO2]. These findings suggest that e[CO2] has a major impact on gluten protein concentration which is associated lower bread quality at e[CO2].