title: Effects of catalase on the accumulation of H(2)O(2) in rice cells inoculated with rice blast fungus, Magnaporthe oryzae.
abstract: Roles of H(2)O(2) in the infection process of Magnaporthe oryzae on rice were investigated. In a leaf sheath assay for up to 48 h post-inoculation, the absence or presence of catalase in the conidia suspension was correlated with the level of accumulated H(2)O(2) in infected leaf cells, as observed by staining with 3',3-diaminobenzidine tetrahydrochloride. In the incompatible interaction, the appearance of autofluorescence or frequency of cell death characterized by granulation (symptoms characteristic of hypersensitive responses) was not significantly affected by the presence of catalase in the conidia suspension. In the leaf blade assay, inoculation of compatible conidia in the presence of catalase produced more severe symptoms than that of conidia in the absence of catalase at 6 days post-inoculation. These results suggest that, in this host-parasite interaction, the primary role of host-produced H(2)O(2) is in limiting hyphal growth after penetration through toxic action. Furthermore, in incompatible interactions, H(2)O(2) is implied not to be a major mediator of hypersensitive cell death.
authors.affiliation: Division of Plant Sciences, National Institute of Agrobiological Sciences, Kannondai, Tsukuba, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Tanabe
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nishizawa
authors.forename: Eiichi
authors.initials: E
authors.lastname: Minami
mesh_terms: D002374:Catalase / Q000378:metabolism* / Q000494:pharmacology; D016923:Cell Death; D002478:Cells, Cultured; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000378:metabolism*; D020082:Magnaporthe / Q000472:pathogenicity*; D012275:Oryza / Q000378:metabolism* / Q000382:microbiology; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D013172:Spores, Fungal / Q000472:pathogenicity
chemical_list: D006861:Hydrogen Peroxide; D002374:Catalase