Isolation and characterization of cgmafi gene which encodes a map kinase from colletotrichum gleoesporioides

Abstract

The causative agent of anthracnose disease in a wide variety of crops, Colletotrichum gloeosporioides, infects plant via specialized cell known as the appressorium. In order for cell to differentiate into its infection structure, cell wall remodeling is crucial, Modification of cell wall structure is known to be involved throughout the process of morphological changes in jilamentous fungi, In this research, we isolate and characterize a MAP kinase designated CgMAF I which is homologous to the Saccharomyces cereviseae MAP kinase SIt2 which is involved in the regulation of cell wall biosynthesis in yeast, To further understand the function of this gene with regard to the infection process, targeted disruption of CgMAFI was carried out, Mutant of CgMAFI designated cgmajJ, showed pleiotropic phenotypes ranging from reduced conidiation, hyperbranching hyphal morphology in nutrient limiting condition, inability to form normal appressorium to the lost of pathogenicity, On inductive sur/aces, the terminal end of germ tube formed swollen structure which is smaller than the mature appressorium of wild type and was unmelanized. Abnormal appressorium formation could well contribute to the inability to penetrate plant tissue thus rendering the mutant nonpathogenic,