title: The Magnaporthe grisea class VII chitin synthase is required for normal appressorial development and function.
abstract: The plant pathogenic fungus Magnaporthe grisea is able to enter its host via appressorium-mediated penetration. Earlier investigations have shown that these infection structures are rich in the cell wall polysaccharide chitin. Previously, we have described how the transcription of a class VII chitin synthase-encoding gene CHS7 is completely dependent on the putative transcription factor Con7p during the germination of conidia, and how con7(-) mutants are unable to form appressoria under any conditions tested. Because of the pleiotropic effects of the con7(-) mutation, we examined the consequences of the targeted deletion of CHS7. The chs7(-) mutants generated were unable to form appressoria on artificial surfaces, except following the application of the exogenous inducers 1,16-hexadecanediol and cyclic adenosine monophosphate. The appressoria formed had a reduced chitin content and were often found to be smaller and misshapen compared with the wild-type. chs7(-) mutants were significantly reduced in their ability to enter rice plants, but growth in planta was not affected. Reverse transcriptase-polymerase chain reaction analysis demonstrated that CHS7 transcription was strongly induced on germination of spores, and a green fluorescent protein-tagged Chs7p protein was found to be produced abundantly during infection-related morphogenesis. Together, these data suggest that the class VII chitin synthase Chs7p of M. grisea is required for normal appressorium formation and function.
authors.affiliation: IBWF e.V., Institute for Biotechnology and Drug Research, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Odenbach
authors.forename: Eckhard
authors.initials: E
authors.lastname: Thines
authors.forename: Heidrun
authors.initials: H
authors.lastname: Anke
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Foster
mesh_terms: D001483:Base Sequence; D002687:Chitin Synthase / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D018076:DNA, Complementary; D017353:Gene Deletion; D005800:Genes, Fungal; D049452:Green Fluorescent Proteins / Q000235:genetics; D020082:Magnaporthe / Q000201:enzymology* / Q000235:genetics; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D049452:Green Fluorescent Proteins; D002687:Chitin Synthase