Independent and combined effects of elevated CO2 and post-anthesis heat stress on protein quantity and quality in spring wheat grains

Abstract

Spring wheat plants were grown under two CO₂ concentrations (380 and 550 μmol mol^-1) and two temperature treatments (ambient and post-anthesis heat stress) to investigate the effects of elevated CO₂ and heat stress on grain protein quality. Contents of protein components, glutenin macropolymers (GMP) and amino acids in grains decreased due to elevated CO₂, while increased by high temperature. The combination of elevated CO₂ and heat stress increased the contents of total protein and albumin, but decreased the contents of gliadin and glutenin, while the content and particle size distribution of GMP as well as the contents of amino acids were not significantly affected. Furthermore, we found that the content and particle size distribution of GMP were not only determined by the contents of proteins and high-molecular-weight glutenin subunits, but also related to the contents of amino acids containing disulfide bonds, which favor the formation of large insoluble polymers.

Keywords: Amino acid; Elevated CO(2); Gluten proteins; Glutenin macropolymers; Glutenin subunits; High temperature; Spring wheat.