DNA methylation levels of TaP5CS and TaBADH are associated with enhanced tolerance to PEG-induced drought stress triggered by drought priming in wheat.

Drought priming is a promising strategy to enhance tolerance to recurred drought in wheat. However, the underlying mechanisms of priming-induced tolerance are far from clear. Here, three different priming intensities (P1D, P2D, P3D) and two varieties with different sensitivities to drought priming were used to investigate the effects and mechanisms of drought priming. Results showed light (P1D) or moderate (P2D) drought priming intensity induced positive effects for the drought sensitive variety (YM16), while high (P3D) priming intensity brought a negative impact on the plant drought resistant. For drought insensitive one (XM33), light priming intensity had no significant effect on tolerance to drought, while moderate or high intensity showed better priming effects. Moderate priming induced higher leaf water potential and also the osmolytes levels. Consistent with the proline and betaine, the related synthetic enzymatic activities, as well as the expression of TaP5CS and TaBADH were higher in P2D in YM16 and P3D in XM33. The contents of proline and betaine showed a positive correlation with activities of SOD, CAT, GR, AsA, and GSH contents, and a negative correlation with O2.-, H2O2, and MDA contents. Further analysis revealed CG demethylation of ATG-proximal regions in the promoter of TaP5CS and TaBADH were involved in promoting the synthesis of proline and betaine in primed plants. Collectively, these findings demonstrate drought priming effect was variety independent but depended on the priming severity, and demethylation of TaP5CS and TaBADH involved in the accumulation of osmolytes which contribute to the enhanced drought tolerance induced by priming.

Effect of High-Molecular Weight Glutenin Subunits (HMW-GSs) on Gluten Polymerization during Biscuit Making: Insights from Experimental and Molecular Dynamics Simulation Study.

The effect of high-molecular weight glutenin subunits (HMW-GSs) on gluten polymerization during biscuit making was investigated using a set of HMW-GS deletion lines. Results showed that the deletion of HMW-GSs improved the biscuit quality compared with the wild type (WT), especially in x-type HMW-GS deletion lines. Slight gluten depolymerization was observed during dough mixing, while progressive gluten polymerization occurred during biscuit baking. The deletion of HMW-GSs suppressed the polymerization of glutenin and gliadin compared with the WT during biscuit baking, especially in x-type HMW-GS deletion lines. These actions resulted in less elevation of the intermolecular ß-sheet and ordered α-helix and altering the disulfide (SS) conformation to a less stable conformation in HMW-GS deletion lines compared with the WT during baking. Molecular dynamics simulation analysis further demonstrated that x-type HMW-GSs had higher thermal stability compared with y-type HMW-GSs during heating.