MICHANISMS OF SIGNAL TRANSDUCTION AND GENE EXPRESSION OF THE PLANT ACTIVE DEFENSE GENES IN PLANT MICROBE INTERACTION

本研究旨在阐明植物主动防御反应相关基因的信号转导和调控机制。本研究对植物主动防御基因激活和失活的信号转导途径的分子基础、顺式和反式作用因子进行了系统的研究，重点研究了豌豆病原菌Mycosphaerella pinodes产生的激发子和抑制子对豌豆主动防御反应中PAL和CHS基因信号转导和调控的影响。详细的研究现状是，1。诱导子能促进PIP和PIP_2的磷酸化，而抑制子则明显抑制PIP和PIP_2的磷酸化。Suppressor不仅抑制PM-ATP酶活性，而且抑制PIP和PIP_2的磷酸化，提示ATP酶与PI-、PIP-激酶相互干扰，阻断PM-ATP酶活性。 关于我们 结果以非常类似于真菌抑制子的方式延迟PAL和CHS表达的诱导.对PAL基因的两个成员（PSPAL 1和PSPAL 2）和CHS基因的两个成员（PSCHS 1和PSCHS 2）在一个多基因小家族中的结构和基因组织进行了测定。将PSPAL 1和PSPAL 2的启动子序列缺失片段与含有报告基因的植物表达载体连接，通过电穿孔法导入豌豆原生质体，并检测诱导子的诱导和抑制子的抑制。在两个PSPAL基因中负责诱导子诱导的顺式元件都含有框2和框4的共有序列基序，而两个PSCHS基因都含有框2.3.通过凝胶阻滞试验和体外DNA酶I足迹分析确定PSPAL 1和PSPAL 2中负责激发子诱导的反式作用因子和顺式调节元件。至少有两个核结合蛋白被发现参与激发子诱导，识别AT丰富的序列基序。少

The object of this research is to elucidate the mechanisms of signal transduction and control of the genes involved in plant active defense responses. We have characterized the molecular basis for the signal transduction pathway and cis- and trans-acting factors involved in the activation and deactivation of plant active defense genes, particularly focused on the study of the effects of elicitor and suppressor produced by a pea pathogen, Mycosphaerella pinodes, on the signal tansduction and the regulation of the genes encodig PAL and CHS in in pea active defense responses. Details of the current status of the studies are,1. The phosphorylation of PIP and PIP_2 by lipid kinase was stimulated by the treatment with elicitor, but it was distinctively suppressed in the concomitant presence of suppressor. Suppressor inhibits not only PM-ATPase but also the phosphorylation of PIP and PIP_2, which suggests that ATPase and PI-, PIP-kinases cross-talk each other and blocking PM-ATPase activity r … More esults in delaying the induction of the expression of PAL and CHS in a manner very similar to a fungal suppressor.2. Structure and gene organization of the two members of PAL gene (PSPAL1 and PSPAL2) and two members of CHS gene (PSCHS1 and PSCHS2) in a small multigene family were determined. Sequentially deleted promoter fragment of PSPAL1 and PSPAL2 connected to a plant expression vector containing the reporter gene was introduced into pea protoplasts by electroporation, and induction by elicitor and suppression by suppressor was examined. Cis- element responsible for elicitor induction in both PSPAL genes contain consensus sequence motifs of box 2 and box 4, whereas both PSCHS genes contain box 2.3. Trans-acting factor(s) and cis-regulatory elements responsible for elicitor-induction in PSPAL1 and PSPAL2 were defined by gel retardation assay and in vitro DNAse I-footprinting analysis. At least two nuclear binding proteins were found to be involved in elicitor-induction which recognize AT rich sequence motifs. Less