| In order to investigate the mechanism of gluten quality formation in different wheat varieties,Xinong 20, Xinong 836, Zhoumai 18 and Xinong 977 with different gluten strength were used as materials to compare and analyze the differences in gluten structure characteristics, protein accumulation dynamics during grain filling, nitrogen metabolism and the expression of genes associated with storage protein biosynthesis. The influences of nitrogen metabolism and storage protein biosynthesis on the quality formation of wheat were investigated from physiological and transcriptional perspectives. The results showed that, the dough development time, dough stability time and protein weakening of Xinong 20 were highest, followed by Xinong 836, Zhoumai 18 and Xinong 977. The contents of disulfide bond and β-sheets in the gluten obtained from Xinong 20 were the highest, but the surface hydrophobicity and ratio of α-helix to β-sheets were lower, appearing as the more compact microstructure of gluten.The gliadin, glutenin and GMP accumulated rapidly in Xinong 20 grains during grain filling, leading to higher contents of total protein, gliadin, glutenin and GMP at maturity than those in the other three wheat grains. Moreover, the activities and gene expression levels of glutamine synthase(GS) and glutamate pyruvate transaminase(GPT) in the flag leaves and grains were the highest in Xinong 20, which enhanced the metabolism of amino acids in the flag leaves and grains.The expression levels of storage protein biosynthesis related genes, including x/y-HMW, LMW-A/B/D, TaGAMyb, TaPBF, TaSPA, TaPDIL2-1, TaSUMO1 and TaPPIase were also highest in Xinong 20.It can be concluded that the high expression levels of genes associated with nitrogen metabolism and storage protein biosynthesis during grain filling were the main reasons for promoting the synthesis and aggregation of grain storage proteins, thereby improving the processing quality of wheat gluten. |
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