Molecular Characterization and Evolution of Self-Incompatibility Genes in Arabidopsis thaliana: The Case of the Sc Haplotype
Molecular Characterization and Evolution of Self-Incompatibility Genes in Arabidopsis thaliana: The Case of the Sc Haplotype
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DOI：
10.1534/genetics.112.146787
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发表时间：
2013-03-01
期刊：
影响因子：
3.3
通讯作者：
Nasrallah, Mikhail E.
中科院分区：
文献类型：
--
作者：
Dwyer, Kathleen G.;Berger, Martin T.;Nasrallah, Mikhail E.
拟南芥谱系中由自交不亲和性强制的异交交配模式转换为自交可育性与突变相关，所述突变使包括自交不亲和性（SI）特异性决定S位点单倍型、S位点受体激酶（SRK）和S位点富含半胱氨酸（SCR）基因以及SI所需的非连锁修饰基因座的两个基因中的一个或两个失活。所有分析A。拟南芥S基因座单倍型属于SA、SB或SC单倍型组。在这三种单倍型中，SC单倍型是最不好表征的。它的SRKC基因可以编码一个完整的开放阅读框，虽然没有功能数据，而其SCRC序列尚未分离。因此，不知道什么突变与该单倍型的失活相关。在这里，我们报告我们的分析Lz-0加入和其高度重排SC单倍型的特点。我们描述了它的SCRC基因的分离，以及随后的分离SCRC序列从其他含SC的加入和从A。lyrata S36单倍型，其是A.拟南芥SC单倍型通过使用嵌合SRK和SCR基因与SC和S36衍生序列构建的转化实验，我们表明，SRKC和SCRC基因的LZ-0和至少一些其他SC-含有加入是非功能性的，尽管SCRC编码功能全长蛋白。我们确定了可能的突变，导致这些基因的失活，并讨论了我们的结果的上下文中的S-位点失活的机制在A。thaliana.
The switch from an outcrossing mode of mating enforced by self-incompatibility to self-fertility in the Arabidopsis thaliana lineage was associated with mutations that inactivated one or both of the two genes that comprise the self-incompatibility (SI) specificity-determining S-locus haplotype, the S-locus receptor kinase (SRK) and the S-locus cysteine-rich (SCR) genes, as well as unlinked modifier loci required for SI. All analyzed A. thaliana S-locus haplotypes belong to the SA, SB, or SC haplotypic groups. Of these three, the SC haplotype is the least well characterized. Its SRKC gene can encode a complete open-reading frame, although no functional data are available, while its SCRC sequences have not been isolated. As a result, it is not known what mutations were associated with inactivation of this haplotype. Here, we report on our analysis of the Lz-0 accession and the characterization of its highly rearranged SC haplotype. We describe the isolation of its SCRC gene as well as the subsequent isolation of SCRC sequences from other SC-containing accessions and from the A. lyrata S36 haplotype, which is the functional equivalent of the A. thaliana SC haplotype. By performing transformation experiments using chimeric SRK and SCR genes constructed with SC- and S36-derived sequences, we show that the SRKC and SCRC genes of Lz-0 and at least a few other SC-containing accessions are nonfunctional, despite SCRC encoding a functional full-length protein. We identify the probable mutations that caused the inactivation of these genes and discuss our results in the context of mechanisms of S-locus inactivation in A. thaliana.