Effect of different water supply on accumulation of high molecular weight glutenin subunits and glutenin macropolymers in near-isogenic wheat lines

Accumulations of high molecular weight glutenin subunits (HMW-GS) and glutenin macropolymer (GMP) in wheat grains are important indicators of grain quality. Two near-isogenic wheat lines, Line 11 (HMW-GS null, 7 + 9, 5 + 10) and Line 12 (HMW-GS null, 17 + 18, 5 + 10), were used to evaluate the impacts of different water supply on HMW-GS and GMP accumulation, and the GMP particle distributions in the grains. Three irrigation levels were implemented in a field and a pot experiment, respectively. Results indicated that drought is beneficial for grain desiccation in the two wheat lines at late filling stage. Compared to mild and excess watering, the total HMW-GS concentration at maturity was much lower when subjected to soil water deficit. Both drought and excess watering led to a reduced glutenin particle size and GMP content at maturity, indicating that a mild water supply could promote the accumulation of GMP and formation of lager glutenin particles. As opposed to Line 12, Line 11 showed an increase in accumulation of GMP and larger glutenin polymers.