Salt stress increases content and size of glutenin macropolymers in wheat grain

•Post-anthesis salinity reduced wheat yield, increased grain Na+ and K+ contents.•Salinity increased content of high molecular weight glutenin subunits (HMW-GS).•Salinity increased glutenin macropolyers (GMP) content and large GMP fraction.•Fortified Na+ and K+ improved HMW-GS and GMP in wheat grains.

Addition of salt solution in making wheat dough improves viscoelasticity. However, the effect of native salt fortification on dough quality is unclear. Here, wheat plants were subjected to post-anthesis salt stress to modify salt ion content in grains. The contents of Na+ and K+, high-molecular-weight glutenin subunits (HMW-GS), glutenin macropolyers (GMP) and amino acids in mature grains were measured. As NaCl concentration in soil increased, grain yield decreased while Na+ and K+ contents increased. The contents of amino acids, HMW-GS and GMP in grains also increased, especially when NaCl concentration exceeded 0.45%. Fraction of GMP larger than 10 μm was also increased. Na+ and K+ contents were significantly positively correlated to GMP and total HMW-GS contents, and to large GMP fraction.