Genetic adaptation to ammonium sustains wheat grain quality and alleviates acclimation to CO₂enrichment

Abstract

Plants synthesize protein through assimilating inorganic nitrogen. Yet, the extent to which soil nitrogen sources alter crop responses to atmospheric CO2remains uncertain. We assessed wheat (Triticum aestivumL.) biomass under CO2enrichment in genotypes that demonstrated a preference for ammonium (NH4+) or nitrate (NO3−), and contrasting degrees of NH4+tolerance. Nitrogen-form preference, but not NH4+tolerance, correlated with CO responses. Notably, NH4+-preferring genotypes maintained higher biomass and sustained grain nitrogen concentrations, thus avoiding CO2acclimation, the decline in biomass stimulation after prolonged exposure to CO2enrichment. Furthermore, NH4+nutrition accelerated flowering and increased spike biomass. Breeding for NH4+-adapted genotypes may not only improve climate resilience, but also potentially accelerate development and increase yield without any penalty on grain quality. Because wheat provides 20% of the protein and carbohydrate in the human diet, our study provided strategies to sustain food security under the atmospheric conditions anticipated in the future.HighlightBreeding for NH4+-adapted genotypes may not only improve climate resilience, but also potentially accelerate development and increase yield without any penalty on grain quality under elevated CO2atmospheres.