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【目的】研究普通小麦品种选育过程中低分子量谷蛋白亚基(LMW-GS)的变化特性,理解该基因家族成员多样性的起源,并为小麦品质改良提供参考。【方法】以3套小麦高代杂交品系(F5/F6)为材料,利用毛细管电泳(CE)技术从储藏蛋白水平鉴定LMW-GS亚基的变化;根据GenBank中已公布的LMW-GS编码序列设计特异性引物,进行PCR扩增、克隆、测序及序列分析。【结果】毛细管电泳结果表明,与亲本相比,高代供试品系均保持了相对稳定的LMW-GS数目,但多个亚基在籽粒中的最终含量却发生明显变化;同时,测试品系还产生了亲本所不具有的新条带。对克隆获得的54条序列(GenBank登录号KC222070-KC222121和KC478714-KC478715)进行序列分析,均具有LMW-GS的典型结构,包括相对保守的信号肽、存在丰富变异的中间重复区及保守的C-端,因此属于LMW-GS基因家族成员;子代与对应亲本的相似性分析表明,3套材料中均存在极端保守序列,子代序列与其相应父本序列完全一致,且都属于LMW-m型亚基;相对保守序列所占比例最大,由于微弱的SNPs,双亲都充当变异序列的供体;蛋白质序列分析还揭示了额外Cys亚基的产生过程。此外,还发现含10个或11个半胱氨酸(Cys)残基的LMW-GS。Cys残基的变异主要发生在C-端Ⅲ区,只有1条序列的Cys变异发生在C-端Ⅱ区。【结论】小麦品种选育过程,父源性的LMW-m型低分子量谷蛋白亚基较其它类型亚基更趋于序列的保守,SNPs则是产生LMW-GS多样性的主要动力。
【Objective】 The objective of this study was to investigate the variation characteristics of low molecular weight glutenin subunits (LMW-GS) during the breeding of common wheat varieties, understand the origin of the diversity of members of this gene family and provide references for the improvement of wheat quality. 【Method】 Three wheat hybrids (F5 / F6) were used as material to identify the LMW-GS subunit from the level of storage protein by capillary electrophoresis (CE). According to the published LMW-GS coding sequence in GenBank Specific primers were designed for PCR amplification, cloning, sequencing and sequence analysis. 【Result】 The results of capillary electrophoresis showed that the relative numbers of LMW-GS in the high-yielding lines maintained a relatively stable level compared with the parental lines, but the final contents of multiple subunits in the grain changed significantly. At the same time, Produced a new band does not have the parents. Sequence analysis of 54 sequences (GenBank accession numbers KC222070-KC222121 and KC478714-KC478715) obtained by cloning all showed the typical structure of LMW-GS, including relatively conserved signal peptide, intermediate repetitive region with abundant variation and conservative C - end, and therefore belong to the LMW-GS gene family members; similar analysis of progeny and their corresponding parents showed that the three sets of materials are extremely conserved sequences, the progeny sequence and its corresponding paternal sequence is exactly the same, and all belong to the LMW-m Type subunits. The relatively conserved sequences account for the largest proportion, and both parents act as donors to the variant sequences due to weak SNPs. Protein sequence analysis also reveals the generation of extra Cys subunits. In addition, LMW-GS containing 10 or 11 cysteine (Cys) residues was also found. The variation of Cys residues occurred mainly in the C-terminal region Ⅲ, and only one sequence of Cys mutation occurred in the C-terminal region Ⅱ. 【Conclusion】 Parental LMW-m low-molecular-weight glutenin subunits tend to conserve sequences more than other types of subunits during wheat breeding. SNPs are the main motives for LMW-GS diversity.