The Study On The Characteristics Of The Low-molecular-weight Gluten In Subunits In The Formation Of The Wheat Varietis

LMW-GS (Low-molecular-weight glutenin subunits) accounted for about70%of thetotal amount of glutenins in endosperm. Wheat glutenin, consist of HMW-GS (high molecularweight glutenin subunits) and LMW-GS, play an important role in wheat flour processingquality by influencing the viscoelasticity and extensibility of dough.To understand the variation features of LMW-GS in the formation of wheat cultivars, Inthis work, the seeds of three sets of hybrid materials (F5/F6), together with theircorresponding parents, were used to test the variability of the LMW-GS by the capillaryelectrophoresis (CE). A series of specific primers, designed according to the genetic sequencepublished in GenBank,54the LMW-GS genes were cloned.1. The results of CE indicated that all the tested lines contained the relatively stablenumbers of LMW-GS compared to the parents, while the accumulation amount of severalsubunits increased significantly.2. On the basis of the sequence analysis, all of the54genes (GenBank accessionnumbers from KC222070to KC222121, and from KC478714to KC478715) belonged to theLMW-GS gene family because of their typical structure of LMW-GS, including the relativelyconserved signal peptides, intermediate repeating regions with abundant variations and theconserved C-terminal domain.Their lengths of the open reading frame (ORF) were from768bpto1128bp, which encode the proteins containing256-376amino acid residues.3. The alignment results of the amino acid sequences which deduced from the nucleotidesequences showed that the signal peptides were relatively conserved. However, there wereindividual amino acid variations. According to the N-terminal sequence, the cloned sequencescould be divided into six kinds: the N-terminal of group1start with ISQQQ-(3sequences),group4.2start with MERSHIPS-(1sequence), group5start with METSRV-(14sequences),group6start with METRCIP-(25sequences), group7.1start with METSCIP-(2sequences) and group7.2start with METSCIS-(7sequences).4. It was also found the fine procedure of the extra Cys residue in the LMW-GS during the formationof wheat cultivars.5. The similarity alignment between the advanced lines and their parents revealed that allthe three sets of hybrid materials shared the extremely conserved sequences with theirrelevant parental lines and all these common sequences belonged to LMW-m subunits. Therelatively conserved sequences originated from SNPs were the major proportion and bothparents have been acted as their donors.6. The sequence of LMW-GS which cloned in the present study contains11Cys residues(KC222071),10residues (KC2220741),9Cys residues (KC222109) and7Cys residues (16).The variation of Cys residues mainly occurred in the C-terminal region Ⅲ, while only onevariation in the C-terminal regionⅡ.