Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA.
J Exp Bot. 2010 Apr;61(7):1897-906. doi: 10.1093/jxb/erp393. Epub 2010 Jan 22.
Molecular genetic studies of self-incompatibility (SI) can be difficult to perform in non-model self-incompatible species. Recently, an Arabidopsis thaliana transgenic model was developed for analysis of the SI system that operates in the Brassicaceae by inter-species transfer of genes encoding the S-locus receptor kinase (SRK) and its ligand, the S-locus cysteine-rich (SCR) protein, which are the determinants of SI specificity in the stigma and pollen, respectively. This article reviews the various ways in which the many advantages of A. thaliana and the extensive tools and resources available in this model species have allowed the use of transgenic self-incompatible SRK-SCR plants to address long-standing issues related to the mechanism and evolution of SI in the Brassicaceae. It also presents the unexpected results of a candidate gene approach aimed at determining if genes related to genes previously reported to be involved in the SI response of Brassica and genes required for disease resistance, which exhibits many similarities to the SI response, are required for SI in A. thaliana. These various studies have provided a novel insight into the basis of specificity in the SRK-SCR interaction, the nature of the signalling cascade that culminates in the inhibition of 'self' pollen, and the physiological and morphological changes that are associated with transitions between the outbreeding and inbreeding modes of mating in the Brassicaceae.
自交不亲和（SI）的分子遗传学研究在非模式自交不亲和物种中进行可能较为困难。最近，开发了拟南芥转基因模型，用于通过种间转移编码 S 位点受体激酶（SRK）及其配体 S 位点富含半胱氨酸（SCR）蛋白的基因来分析在十字花科中起作用的 SI 系统，这些基因分别是柱头和花粉中 SI 特异性的决定因素。本文综述了拟南芥的诸多优势以及该模式物种中广泛可用的工具和资源在利用转基因自交不亲和 SRK-SCR 植物解决与十字花科 SI 的机制和进化相关的长期存在问题方面的各种应用方式。它还介绍了候选基因方法的意外结果，该方法旨在确定与先前报道的参与芸薹属 SI 反应的基因以及与表现出与 SI 反应许多相似性的抗病性相关的基因是否与拟南芥的 SI 相关，这些研究为 SRK-SCR 相互作用的特异性基础、最终导致“自身”花粉抑制的信号级联的性质以及与十字花科中杂交和自交交配模式之间转变相关的生理和形态变化提供了新的见解。
