Molecular and Cellular Analyses of Self and Non-self Recognition Systems in Plants

(1)芸苔属植物自识别系统中花粉s决定因素分析。在芸苔属自交不亲和系统中，已知两个柱头s决定因子；s受体激酶（SRK）和s位点糖蛋白（SLG）。但花粉s -行列式尚不确定。采用多种生物化学和分子生物学方法对油菜花粉提取物和花粉mRNA进行了分析，成功地发现了花粉s决定因子的候选分子。分析了该基因的s特异性、与s位点的连锁关系以及在花药和花粉中的表达模式。进一步，我们对花粉s -决定基因进行了体外分析和转化实验，我们证实了暂命名为SP11的基因是花粉s -决定基因。(2)植物与病原菌相互作用的宿主与非宿主关系中的识别分子。绿假单胞菌是一种广泛侵染单子叶植物的植物致病菌。但在菌株水平上对宿主的特异性比较严格；一些菌株可以攻击水稻，但不能攻击其他植物。当一种不相容的菌株感染水稻时，它会引起过敏反应并导致细胞死亡。摘要用生物化学方法鉴定了一株荷花素作为不相容菌株的标记分子。我们进一步证明，不含fragellin的突变株不会引起过敏反应。

(1)Analysis of pollen S-determinant in self-recognition system of Brassica.In the self-incompatibility system of Brassica, two stigma S-determinants have been known ; S-receptor kinase (SRK) and S-locus glycoprotein (SLG). But the pollen S-determinant was still uncertain. We have analyzed pollen extract and pollen mRNA of Brassica campestris using various biochemical and molecular biological methods and succeeded in founding candidate molecules of the pollen S-determinant. Then we analyzed it S-specificity, linkage to S-locus and expression pattern in anther and pollen. Further we performed an in vitro assay and transformation experiment for the pollen S-determinant, and we confirmed that the gene tentatively termed SP11 is the pollen S-determinant.(2)Recognition molecules in host and non-host relation of plant-pathogen interaction.Pseudomonas avenae is a phytopathogenic bacterium that attacks widely monocot plants. But the host-specificity in the level of strains is rather strict ; some strains can attack rice but not other plant species. When an incompatible strain would infect rice, it induces hypersensitive reactions and caused cell death. As a molecule to be recognized as a marker of an incompatible strain, a fragellin was identified by a biochemical method. We further proved that a fragellin-less mutant strain cannot cause hypersensitive reactions.