四倍体和六倍体小麦品种显示出同源Gli-2位点的α-醇溶蛋白表达存在巨大差异。

Tetraploid and hexaploid wheat varieties reveal large differences in expression of alpha-gliadins from homoeologous Gli-2 loci.

作者信息

Salentijn Elma Mj, Goryunova Svetlana V, Bas Noor, van der Meer Ingrid M, van den Broeck Hetty C, Bastien Thomas, Gilissen Luud J W J, Smulders Marinus J M

机构信息

Plant Research International, Wageningen UR, Wageningen, the Netherlands.

出版信息

BMC Genomics. 2009 Jan 26;10:48. doi: 10.1186/1471-2164-10-48.

DOI:10.1186/1471-2164-10-48

PMID:19171027

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC2636828/

Abstract

BACKGROUND

Alpha-gliadins form a multigene protein family encoded by multiple alpha-gliadin (Gli-2) genes at three genomic loci, Gli-A2, Gli-B2 and Gli-D2, respectively located on the homoeologous wheat chromosomes 6AS, 6BS, and 6DS. These proteins contain a number of important celiac disease (CD)-immunogenic domains. The alpha-gliadins expressed from the Gli-B2 locus harbour fewer conserved CD-epitopes than those from Gli-A2, whereas the Gli-D2 gliadins have the highest CD-immunogenic potential. In order to detect differences in the highly CD-immunogenic alpha-gliadin fraction we determined the relative expression level from the homoeologous Gli-2 loci in various tetraploid and hexaploid wheat genotypes by using a quantitative pyrosequencing method and by analyzing expressed sequence tag (EST) sequences.

RESULTS

We detected large differences in relative expression levels of alpha-gliadin genes from the three homoeologous loci among wheat genotypes, both as relative numbers of expressed sequence tag (EST) sequences from specific varieties and when using a quantitative pyrosequencing assay specific for Gli-A2 genes. The relative Gli-A2 expression level in a tetraploid durum wheat cultivar ('Probstdorfer Pandur') was 41%. In genotypes derived from landraces, the Gli-A2 frequency varied between 12% and 58%. In some advanced hexaploid bread wheat cultivars the genes from locus Gli-B2 were hardly expressed (e.g., less than 5% in 'Lavett') but in others they made up more than 40% (e.g., in 'Baldus').

CONCLUSION

Here, we have shown that large differences exist in relative expression levels of alpha-gliadins from the homoeologous Gli-2 loci among wheat genotypes. Since the homoelogous genes differ in the amount of conserved CD-epitopes, screening for differential expression from the homoeologous Gli-2 loci can be employed for the pre-selection of wheat varieties in the search for varieties with very low CD-immunogenic potential. Pyrosequencing is a method that can be employed for such a 'gene family-specific quantitative transcriptome profiling'.

摘要

背景

α-醇溶蛋白形成一个多基因蛋白家族，由位于三个基因组位点Gli-A2、Gli-B2和Gli-D2的多个α-醇溶蛋白（Gli-2）基因编码，这些位点分别位于小麦同源染色体6AS、6BS和6DS上。这些蛋白质包含许多重要的乳糜泻（CD）免疫原性结构域。与Gli-A2位点表达的α-醇溶蛋白相比，Gli-B2位点表达的α-醇溶蛋白含有较少的保守CD表位，而Gli-D2醇溶蛋白具有最高的CD免疫原性潜力。为了检测高度CD免疫原性α-醇溶蛋白组分的差异，我们使用定量焦磷酸测序方法并分析表达序列标签（EST）序列，确定了各种四倍体和六倍体小麦基因型中同源Gli-2位点的相对表达水平。

结果

我们检测到小麦基因型中来自三个同源位点的α-醇溶蛋白基因相对表达水平存在很大差异，这既体现在特定品种表达序列标签（EST）序列的相对数量上，也体现在使用针对Gli-A2基因的定量焦磷酸测序分析时。四倍体硬粒小麦品种（‘Probstdorfer Pandur’）中Gli-A2的相对表达水平为41%。在源自地方品种的基因型中，Gli-A2频率在12%至58%之间变化。在一些先进的六倍体面包小麦品种中，Gli-B2位点的基因几乎不表达（例如，‘Lavett’中低于5%），但在其他品种中它们占比超过40%（例如，‘Baldus’中）。