Cellular lignification as a factor in the hypersensitive resistance of wheat to stem rust

摘要: Fluorescence microscopy, histochemistry and autoradiography all indicated the cellular accumulation of phenolic compounds during hypersensitive necrosis induced by Puccinia graminis f. sp. tritici in resistant wheat cultivars. Hypersensitivity were observed near-isogenic lines carrying Sr 5 or 6 (at 19°C) alleles for resistance, but not susceptible reactions parent cultivar Marquis ( sr 5, 6), line when tested at 26°C. Toluidine blue staining fluorescence microscopy a material hypersensitively necrotic cells. Removal wall-bound acids with hot alkali caused little loss fluorescent intensity, subsequent delignification chlorine dioxide reduced to negligible levels. Autoradiography, using lignin precursors [ 3 H]-phenylalanine 14 C]-cinnamic acid, showed incorporation label into cytoplasmic regions degenerating host cells, corresponding sites autofluorescence histochemical staining. H]-Phenylalanine incorporated healthy cells fungal structures was lost from both tissue on treatment, some retained Necrotic infected cultivars cell wall degrading enzymes, extraction allowed maceration. The which is alkali-insoluble, enzyme extractable indicates that lignification occurs response. A role as an barrier postulated its direct indirect effect growth discussed.