【作者】 汤承；

【导师】 李名扬； 吴伯骥；

【作者基本信息】 西南大学 ， 园艺学， 2006， 博士

【摘要】 hrp基因在植物革兰氏阴性病原菌中普遍存在，其编码的harpin蛋白是病原菌引起植物过敏反应的主要因子。Wei等首次从Erwinia amylovora Ea321菌株中分离出编码蛋白激发子的hrpN基因并在大肠杆菌中成功表达了harpinEa蛋白，能激发非寄主植物的过敏反应。大量研究证明，harpinEa具有促进植物生长发育、诱导广谱抗病性及抗虫性等多种有益的生物学效应，并对其机理进行了深入研究。尽管不同来源的hrp基因编码的harpin蛋白均有相似的生物学活性，但其生物学活性也存在明显差别。因此，克隆植物病原菌不同生理小种的hrp基因，研究其结构及功能，对于研究植物-病原菌相互作用和开发新型生物农药，具有重要的理论及实践意义。 Erwinia carotovora subsp．Carotovora(Ecc)和Erwinia chrysanthemi(Ech)是世界范围内的重要植物病原菌，由此引起的软腐病是我国蔬菜、花卉等园艺植物的主要细菌病害之一。目前已从这两种菌中发现hrp基因簇，证明了hrpNEcc和hrpNEch基因的编码产物harpinEcc和harpinEch蛋白是引起过敏反应的关键因子。但关于harpinEcc蛋白的理化特性的研究还未见报道，除了引起烟草和拟南芥的过敏反应以及能诱导拟南芥产生对Erwinia carotovora subsp．Carotovora的抗性之外，还没有在其它植物如是粮食、园艺作物上的生物学效应的报告，其诱导抗性的分子机制也不清楚。本研究的目的是从国内患软腐病的作物中分离Erwinia chrysanthemi和Erwinia carotovora subsp．Carotovora菌，克隆并表达hrpN基因，研究其分子特性、遗传多样性及其对生物学效应的影响，并对harpinEcc蛋白的理化特性、在园艺植物上的生物学效应、过敏反应的程度与对园艺作物的生物学效应的关系以及harpinEcc蛋白诱导植物抗性的分子机制等问题进行研究，旨在进一步丰富植物-病更多还原

【Abstract】 hrp genes appear to be universal among many gram negative plant pathogens. The harpins protein coded by hrp is the main factor to elicit in non-host plants or in host plants with race specific resistance a rapid defense associated programmed cell death which usually manifests itself as hypersensitive response (HR). Harpin protein from Erwinia amylovora is the first well characterized elicitor of the HR and hrpN gene is first cloned and over-expression in recombined E. coli. HarpinEa can elicit HR in non-host plants, it has been found to elicit disease resistance response, insect resistance and stimulate the growth of plants, and so on. The mechanism of HarpinEa involving biological effects has been also well studied. Although harpins derived from different species share the similar biological effects, but the biological activity is obviously different. So, To clone hrp genes from different species lived in different environment and study the relationship between their structure-function has remarkable value for understanding the plant-pathogen reaction and development novel pesticides.Erwinia carotovora subsp. Carotovora (Ecc) and Erwinia chrysanthemi (Ech) are pathogens of Soft rots, which cause serious problem to horticulture plants such as vegetables and flowers etc. all over the world. hrp Gene Clusters have been discovered更多还原