Grain storage protein concentration and composition of winter wheat (Triticum aestivum L.) as affected by waterlogging events during stem elongation or ear emergence

Maintaining grain quality of winter wheat under abiotic stresses is important for end-use functional properties. While changes in protein concentration and protein composition have been shown for drought and heat events, knowledge on effects of waterlogging on protein quality are scarce. Therefore, two winter wheat cultivars differing in baking properties were cultivated in a large-scale container experiment and exposed to waterlogging for 14 d at two different growth stages: (1) at BBCH 31 (stem elongation) and (2) at BBCH 51 (beginning of ear emergence). Analysis of protein concentration revealed a significant increase, but protein content per grain was decreased. Analysis of protein composition displayed significant changes after both waterlogging treatments. Waterlogging at stem elongation resulted in a decreased concentration of ω-gliadins. HMW glutenins increased after waterlogging at stem elongation and at ear emergence. In both cultivars, LMW B-type glutenins decreased after waterlogging at stem elongation or at ear emergence. In this study, we could show that waterlogging, occurring in generative developmental stages, enhance grain protein concentration, but not necessarily protein content, and that waterlogging causes shifts in grain protein composition.