Signal perception and intracellular signal transduction in plant pathogen defense.
Disease resistance in plant/pathogen interactions requires sensitive and specific recognition mechanisms for pathogen-derived signals in plants. Cultured parsley (Petroselinum crispum) cells respond to treatment with a crude cell wall preparation derived from the phytopathogenic fungus Phytophthora sojae with transcriptional activation of the same set of defense-related genes as are activated in parsley leaves upon infection with fungal spores. A 13 amino acid core sequence (Pep-13) of a 42 kDa fungal cell wall glycoprotein was identified, which stimulates the same responses as the crude cell wall elicitor, namely macroscopic Ca2+ and H(+)-influxes, effluxes of K(+)- and Cl- ions, production of active oxygen species (oxidative burst), defense-related gene activation, and formation of antifungal phytoalexins. Using [125I]Tyr-Pep-13 as ligand in binding assays, a single-class high-affinity binding site in parsley microsomal membranes and protoplasts could be detected. Binding was specific, saturable, and reversible. By chemical crosslinking, a 91 kDa parsley plasma membrane protein was identified to be the receptor of the peptide elicitor. Isolation of this receptor protein involved in pathogen defense in plants is under way.
Nürnberger
T
T
Abt. Stress- und Entwicklungsbiologie, Institut für Pflanzenbiochemie, Halle.
Wirtz
W
W
Nennstiel
D
D
Hahlbrock
K
K
Jabs
T
T
Zimmermann
S
S
Scheel
D
D
D000890:Anti-Infective Agents / Q000378:metabolism; D007887:Fabaceae; D005656:Fungal Proteins / Q000378:metabolism; D007113:Immunity, Innate; D019684:Magnoliopsida; D008562:Membrane Glycoproteins / Q000378:metabolism; D008954:Models, Biological; D009181:Mycoses / Q000276:immunology*; D010838:Phytophthora; D010935:Plant Diseases; D010936:Plant Extracts / Q000096:biosynthesis; D010946:Plants, Medicinal; D012717:Sesquiterpenes; D015398:Signal Transduction / Q000276:immunology*; D013729:Terpenes; D000094162:Phytoalexins
D000890:Anti-Infective Agents; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D010936:Plant Extracts; D012717:Sesquiterpenes; D013729:Terpenes; C091510:elicitor protein, Phytophthora megasperma; D000094162:Phytoalexins