Signal substances triggering the activation of vir-region of Ti-plasmid in Agrobacterium tunofaciens and its activation mechanism

本文研究了启动根癌农杆菌Ti质粒病毒区激活的信号分子及其激活机制，证实了包括乙酰丁香酮在内的几种低分子量酚类化合物对根癌农杆菌Ti质粒病毒区具有激活作用，乙酰丁香酮在健康和受伤的烟草植株中均未以游离态、糖苷或缩酚形式存在。乙酰丁香酮没有形成的其他酚类化合物在受伤的组织。本研究在烟草愈伤组织中检测到乙酰丁香酮。由于本工作所研究的烟草植株的健康和受伤组织中均不含乙酰丁香酮，因此乙酰丁香酮似乎不是植物中的一般信号分子，而是烟草植物中的特征化合物。每种植物都可能形成自己特有的信号分子，能激活Ti质粒病毒区的低分子量酚类化合物的结构相似性，可能给我们一个启示，让我们理解为什么细菌能捕获这么多属于不同类别的酚类化合物作为信号分子。

Signal molecules triggering the activation of vir-region of Ti-plasmid in Agrobacterium tumofaciens and its activation machanizm were investigated.It was confirmed that several low molecular weight phanolic compounds including acetosyringone have ability to activate the vir-rigeion of Ti-plasmid in Agrobacterium tumofaciens.Acetosyringone was not found in the healthy and wounded tobacco plants as free state, glycosides, or depsides. Acetosyringone was not formed from the other phenolic compounds in the wounded tissues. Acetosyringone was detected in the calluses of tobacco plant in this study. Since all the founr plants investigated in this work did not contain acetosyringone in their healthy and wounded tissues, acetosyringone did not seem to be a general signal molecule in plants but to be a characteristic compound in tobacco plant. Each plant may have form the signal molecules characteristic to itself.Structural similarity of the low molecular weight phenolic compounds which can activate the vir-region of Ti-plasmid could give us a hint to understand why the bacterium can catch so many phenolic compounds being belonged to different categoriesas as the signal molecules.