title: A mitogen-activated protein kinase kinase required for induction of cytokinesis and appressorium formation by host signals in the conidia of Colletotrichum gloeosporioides.
abstract: Differentiation of fungal conidia of phytopathogens into the infection structure, appressorium, requires contact with a hard surface and host signals. The molecular signaling involved in the induction of this differentiation is poorly understood. We report the cloning of a mitogen-activated protein kinase kinase (MEK), CgMEK, from Colletotrichum gloeosporioides and its role in the induction of these developmental processes involved in pathogenesis. Disruption of CgMEK1 resulted in the loss of its ability to form appressoria in response to the host's signals and a loss of virulence. Results of confocal microscopic examination of germinating conidia of the gene-disrupted mutants were similar to those for wild-type conidia treated with an MEK inhibitor, suggesting that CgMEK1 is involved in two developmental processes in the differentiation into appressorium: (1) polarized cell division, with the preferential increase in F-actin in one of the daughter nuclei after nuclear division and the formation of septum; and (2) differentiation of the germ tube into an appressorium. CgMEK1 is required for the differentiation.
authors.affiliation: Department of Biochemistry, Ohio State University, 1060 Carmack Road, Columbus, Ohio 43210, USA.
authors.forename: Y K
authors.initials: YK
authors.lastname: Kim
authors.forename: T
authors.initials: T
authors.lastname: Kawano
authors.forename: D
authors.initials: D
authors.lastname: Li
authors.forename: P E
authors.initials: PE
authors.lastname: Kolattukudy
mesh_terms: D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D002455:Cell Division; D016764:Cell Polarity; D003001:Cloning, Molecular; D020231:Colletotrichum / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D005030:Ethylenes / Q000037:antagonists & inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D005638:Fruit / Q000382:microbiology / Q000502:physiology; D017353:Gene Deletion; D018525:Germination; D019770:Lauraceae / Q000382:microbiology / Q000502:physiology; D048369:MAP Kinase Kinase 1; D018613:Microscopy, Confocal; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation / Q000187:drug effects; D010935:Plant Diseases / Q000382:microbiology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012331:RNA, Fungal / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D016415:Sequence Alignment; D015398:Signal Transduction / Q000187:drug effects; D013172:Spores, Fungal / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics; D014885:Waxes / Q000494:pharmacology
chemical_list: D000199:Actins; D005030:Ethylenes; D005419:Flavonoids; D012331:RNA, Fungal; D012333:RNA, Messenger; D014885:Waxes; C036216:ethylene; D017346:Protein Serine-Threonine Kinases; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one