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

（1）芸苔属植物花粉自我识别系统中S-决定子的分析在芸苔属植物自交不亲和系统中，已知有两个柱头S-决定子：S-受体激酶（SRK）和S-位点糖蛋白（SLG）。但花粉的S-决定簇仍不确定。本研究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-决定簇的候选分子。分析了该基因的S特异性、与S位点的连锁性以及在花药和花粉中的表达模式。进一步对花粉S-决定簇进行了离体测定和转化实验，证实了暂定名为SP11的基因是花粉S-决定簇。（2）植物-病原菌互作中的寄主识别分子和非寄主识别分子燕麦假单胞菌（Pseudomonasavenae）是一种广泛侵染单子叶植物的植物病原细菌。但在菌株水平上对寄主的专一性比较严格，有些菌株能侵染水稻而不能侵染其他植物。当不亲和菌株侵染水稻时，会引起过敏反应并导致细胞死亡。作为被识别为不相容菌株的标志物的分子，通过生物化学方法鉴定了fragellin。我们进一步证明了无碎片蛋白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.