小麦低分子量麦谷蛋白基因座位Glu-D3位点的分子进化

Molecular Evolution of Low-Molecular-Weight Glutenin Gene Locus Glu-D3 in Wheat

小麦Glu-3位点含有低分子量麦谷蛋白(low-molecular-weight glutenin subunit, LMW-GS)基因、部分醇溶蛋白基因和抗病基因,其对品质改良和抗病育种具有重要意义。为了解析小麦Glu-D3位点和探讨其六倍体化,本研究从已发表的普通小麦基因组中截取了Glu-D3位点序列。该序列共7.51 Mb,包含49.07%的重复序列/元件。我们从中预测得到共163个基因,其中8个LMW-GS基因,6个醇溶蛋白基因和34个抗病基因。在整个位点,基因间的平均距离为46.07 kb。通过和普通小麦D基因组供体粗山羊草Glu-D3位点的共线性分析,我们发现六倍体化使得普通小麦的Glu-D3位点发生了两处片段倒置(0.91～3.12 Mb和3.97～5.14 Mb)和两处大片段(0.91～3.12 Mb和3.97～5.14 Mb)插入,但未对LMW-GS基因的编码区造成影响。进化树分析表明,普通小麦Glu-D3位点的基因可能来源于不同的粗山羊草品系。这项工作将有助于人们理解Glu-D3位点的组成和结构以及六倍体化对D基因组结构等方面的影响。

Wheat Glu-3 locus contains low-molecular-weight glutenin subunit(LMW-GS),partial gliadin and disease resistance genes,and it is of great significance to quality improvement and disease resistance breeding.In order to dissect Glu-D3 locus in wheat and explore its hexaploidization,the Glu-D3 locus sequence of common wheat was obtained from the published genome data in this study.The locus was 7.51 Mb with 49.07%repetitive DNA.In the locus,163 genes were predicted with an average gene density of 46.07 kb/gene,among which there were eight LMW-GS genes,six gliadin genes and 34 disease resistance genes.In the syntenic analysis with the progenitor locus in Aegilops tauschii,the Glu-D3 locus of common wheat comprised two large fragment inversions(at the positions 0.91~3.12 Mb and 3.97~5.14 Mb)and two huge insertions(at the positions 0.91~3.12 Mb and 3.97~5.14 Mb),which might be induced by wheat hexaploidiz ation.However,the coding sequences of homological LMW-GS genes between the two loci kept conserved.Phylogenetic analysis indicated that genes in the Glu-D3 locus of common wheat might originate from more than one Ae.tauschii genotypes.This work would undoubtedly facilitate elucidating not only the gene composition and structure of Glu-D3 locus but also the impact of hexaploidization on the structure of the D genome.