显花植物自体和异体花粉识别的分子机理研究(英文)

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。

Molecular Biology of Self and Non-self Pollen Recognition in Flowering Plants

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.