Molecular mechanism or oxidative burst in infected plants and its control mechanism of networks of local nd systemic defense response to infection

为了了解氧化猝发（oxidative burst，OXB）系统在植物主动防御过程中的系统机制，对OXB系统的分子基础、激活机制以及与局部或系统诱导抗性相关的分子和生理变化的动态进行了研究。1）分别从马铃薯和烟草中克隆了两个gp 91 phox同源基因，它们可能是NADPH氧化酶的一个亚基，具有膜蕨蛋白的特征，具有NADPH和钙离子的结合位点，（2）创伤或感染刺激可使OXB系统由失活状态迅速激活，Ca ~（2+）可抑制增强细胞中的OXB>通道阻断剂、钙调蛋白抑制剂或蛋白激酶抑制剂，表明C激酶参与了OXB的诱导。3）通过差异显示或减法克隆了由OXB诱导型激发子刺激的防御代谢相关基因，四、通过使用PVX载体对一些克隆的基因进行基因沉默，证明了负责OXB或NADPH产生的基因在细胞凋亡中起关键作用。针对不相容的疫霉属真菌的防御表达。5）局部OXB的诱导引起局部以及系统诱导的抗性，发送一个高贵的系统信号，引起非增强组织中细胞间连续的Ca^2+内流，然后在增强组织中诱导系统性OXB，从而引发系统性获得性抵抗的诱导。6）信号传递元件对OXB系统诱导的正调控作用可用于植物抗病原免疫的诱导。

Molecular basis of oxidative burst (OXB) system, which was an initial signal for induction of defense response in plants, regulatory mechanisms for activation of the system, and dynamic phases of molecular and physiological changes associated with local or systemic induced resistance were investigated for understanding of a systematic mechanism of plant active defense under the control by oxidative burst Following results were obtained :1 ) Two gp91phox horologes, which may be a subunit of NADPH oxidase, were cloned from potato and tobacco plants, respectively, and they were characterized by membrane fern proteins with binding sites of NADPH and calcium,2 ) The OXB system was rapidly activated from inactive state by wounding or infection stimuli and OXB in the potentiated cells was inhibited by Ca^<2+> channel blockers, calmodulin inhibitors or protein kinase inhibitors, suggesting involvement of a C kinase in induction of OXB.3 ) Defense-metabolism-related genes, which were stimulated by OXB-inducible elicitors, were cloned by mean of differential display or subtraction,4 ) Gene silencing about some of the cloned genes by using a PVX vector demonstrated that genes responsible for OXB or NADPH producer were a crucial role in defense expression against incompatible Phytophthora fungus.5 ) Induction of local OXB caused local as well as systemic induced resistance, dispatching a noble systemic signal which caused a sequential Ca^<2+> influx from cells to cells in non potentiated tissues and then induced systemic OXB at the potentiated tissue for triggering induction of systemic acquired resistance.6 ) A positive regulation of induction of OXB system by signal dispatching elements was suggested to be applicable for induction of plant immunization against pathogens.