中文摘要：

【目的】Rho GTP酶是Ras超家族小G蛋白最主要成员。不同生物均含多种Rho GTP酶，相互之间存在密切关系，并共同参与调控多个信号转导途径。稻瘟菌基因组中存在7个Rho GTP酶，分析它们相互关系意义甚大。【方法】通过RT-PCR分析了MgCdc42不同状态下以及MgRho3插入失活状态下其它Rho GTP酶基因的表达变化。【结果】结果表明MgCdc42可能处于MgRhol、MgRho2和MgRhoX上游，对这些蛋白起正调控作用，对MgRacl和MgRho4起着负调控作用；MgRho3对MgRhol和MgCdc42的表达起正调控，对MgRacl和MgRho4的表达则起负调控作用；MgRho3与MgCdc42间关系复杂。【结论】稻瘟菌RhoGTP酶信号途径复杂，不同RhoGTP酶间存在相互调控关系，这将有助于进一步了解稻瘟菌等丝状真菌RhoGTP酶之间的相互关系。

英文摘要：

[Objective] The Rho GTPases are major members of the Ras superfamily proteins. It is well known that there are several Rho GTPases interacting with each other and regulating several signal transduction pathways in eukaryotes. Genome analysis showed that there are seven putative Rho GTPases in Magnaporthe grisea, and it is essential to study the relationship among these Rho GTPases. [Method] RT-PCR was used to analyze expression patterns of genes encoding these Rho GTPases in different MgCdc42 and MgRho3 mutants. [Result] It was found that MgCdc42 positively controlled expression MgRhol, MgRho2 and MgRhoX and negatively regulated expression MgRacl and MgRho4; however MgRho3 positively regulated expressions MgRhol and MgRho2, but negatively controlled expression MgRho4 and MgRacl. The relationship between MgRho3 and MgCdc42 was complicated. [ Conclusion] There exists sophisticated Rho GTPase signal pathways in the fungus, and they may regulate each other between these Rho GTPases. The result will facilitate understanding the functional relationship of different GTPases in M. grisea and other filamentous fungi.