Scherrer B, Keller B, Feuillet C
Institute of Plant Biology, University of Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland.
Funct Integr Genomics. 2002 May;2(1-2):40-50. doi: 10.1007/s10142-002-0051-9. Epub 2002 Apr 9.
The isolation of genes of agronomic interest such as disease resistance genes is a central issue in wheat research. A good knowledge of the organization and evolution of the genome can greatly help in defining the best strategies for efficient gene isolation. So far, very few wheat disease resistance loci have been studied at the molecular level and little is known about their evolution during polyploidization and domestication. In this study, we have analyzed the haplotype structure at loci orthologous to the leaf rust resistance locus Lr10in hexaploid wheat which spans 350 kb in diploid wheat. Two haplotypes (H1, H2) were defined by the presence (H1) or the absence (H2) of two different resistance gene analogs ( rga1, rga2) at this locus on chromosome 1AS. Both haplotypes were found in a collection of 113 wild and cultivated diploid and polyploid wheat lines and they do not reflect phylogenetic relationships. This indicates an ancient origin for this disease resistance locus and the independent conservation of the two haplotypes throughout the evolution of the wheat genome. Finally, the coding regions of the H1 haplotype RGAs are extremely conserved in all the species. This suggests a selective pressure for maintaining the structural and functional configuration of this haplotype in wheat. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s10142-002-0051-9.
分离诸如抗病基因等具有农学意义的基因是小麦研究中的核心问题。深入了解基因组的组织和进化对于确定高效基因分离的最佳策略有极大帮助。到目前为止，很少有小麦抗病基因座在分子水平上得到研究，对于它们在多倍体化和驯化过程中的进化也知之甚少。在本研究中，我们分析了六倍体小麦中与叶锈病抗性基因座Lr10直系同源的基因座的单倍型结构，该基因座在二倍体小麦中跨度为350 kb。在1AS染色体上的这个基因座，通过两个不同抗病基因类似物（rga1、rga2）的存在（H1）或缺失（H2）定义了两种单倍型。在113份野生和栽培的二倍体及多倍体小麦品系中都发现了这两种单倍型，它们并不反映系统发育关系。这表明该抗病基因座起源古老，且在小麦基因组进化过程中两种单倍型独立保守。最后，H1单倍型抗病基因类似物的编码区在所有物种中都极其保守。这表明在小麦中存在维持该单倍型结构和功能构型的选择压力。本文的电子补充材料可通过位于http://dx.doi.org/10.1007/s10142-002-0051-9的Springer LINK服务器获取。
