Abstract: 【Objective】 MgCdc42 (Cdc42 in Magnaporthe grisea), with high homology to ScCdc42 (Cdc42 in Saccharomyces cerevisiae), has been demonstrated to involve in its morphogenesis and infection process. To further dissect the signaling network, the putative MgCdc42-interacting proteins were analyzed. 【Method】 ScCdc42-interacting protein sequences were first used to BLAST against the M. grisea genome database to retrieve their corresponding analogs. Subsequently, conserved domains of these proteins were compared and expression patterns of their encoding genes in different MgCdc42 mutation states were analyzed by semi-quantitative RT-PCR.【Result】All retrieved analogs of ScCdc42-interacting proteins from the M. grisea database have conserved domains as those in S. cerevisiae. Expression of their encoding genes increased in MgCdc42CA mutant, and decreased in MgCdc42KO mutant. However, MgBem1, Chm1 and MgGic1 in MgCdc42DN mutant remained the same expression level as that in the wild type although MgBem4, MgBoi2, MgCdc24, MgGic2, MgRga1 and Mst20 decreased as expected.【Conclusion】 Taking together, we conclude that there may exist a similar Cdc42 signal pathway in M.grisea as in S. cerevisiae and MgCdc42 plays a key role in the pathway.

Key words: Cdc42, Magnaporthe grisea, Guanine nucleotide exchange factor, GTPase-activating protein