摘要
Fertilization in flowering plants is completed through several recognitionevents, and the first of which is the recognition of pollen by pistil of female reproductivetissue. Self-incompatibility (SI) is an intraspecific reproductive barrier to prevent selfferitilization and widely distributed in flowering plants. In many species, SI shows simplegenetics and is controlled by a single multi-allelic locus, called the S locus. In gametophyticSI (GSI) exemplified by the Solanaceae, Scrophulariaceae and Rosaceae, a class ofribonucleases, called S RNases, have been shown to mediate the stylar expression of SI butnot the pollen expression of SI. The latter appears to be determined by a gene differentfrom those encoding S RNases, often referred to as pollen S gene. The pollen S gene is thecrucial missing part in understanding the biochemical and molecular mechanisms of self andnon-self pollen recognition in flowering plants. Recent genetic analysis of mutationsaffecting the pollen expression of SI has suggested a possible model of how the pollen S geneinteracts with S RNases to achieve self and non-self pollen recognition. Furthermore, wewill present two approaches, S-locus directed transposon tagging and map-based cloning, forcloning the pollen S in Antirrhinum.
显花植物的受精涉及许多识别过程；其中第一个是雌性生殖组织心皮对花粉的识别。自交不亲和性（Ｓｅｌｆ－ｉｎｃｏｍｐａｔｉｂｉｌｉｔｙ，ＳＩ）是一种广泛分布于显花植物的种内生殖障碍。在多数自交不亲和的植物中，ＳＩ的遗传控制比较简单，受控于一个由复等位基因构成的单一位点，称为Ｓ位点。在以茄科、玄参科和蔷薇科为代表的配子体自交不亲和植物中，Ｓ位点编码一类核酸酶，即Ｓ核酸酶（Ｆｉｇ．１），控制ＳＩ在花柱中的表达，但是与花粉自交不亲和性的表达无关。后者可能由与Ｓ核酸酶不同的基因控制，这种基因常被称为花粉Ｓ基因。它是目前了解显花植物花粉识别生化和分子机理的关键。近来；通过对影响花粉ＳＩ表达突变体的分子遗传分析提出了一个花粉Ｓ基因产物如何与Ｓ核酸酶相互作用完成自体和异体花粉识别过程的模型（Ｆｉｇ．２）。另外，描述了两个在金鱼草中克隆花粉Ｓ基因的方法，即Ｓ位点选择性的转座子标记和图位克隆。
