Journal article

Publication year: 1998

Pages: 292-300

Journal: Molecular Plant-Microbe Interactions

Volume number: 11

Issue number: 4

ISSN: 0894-0282

DOI Link: https://doi.org/10.1094/MPMI.1998.11.4.292

Publisher: American Phytopathological Society

Abstract: 
The pathogenesis-related, azide-insensitive generation of superoxide anions (O-2(-)) was comparatively analyzed in near-isogenic barley (Hordeum vulgare cv, Pallas) lines carrying the powdery mildew (Erysiphe graminis f. sp, hordei) resistance genes Mla12, Mlg, and mlo5, respectively, by the microscopic detection of nitroblue tetrazolium (NET) reduction to dark blue formazan dyes, These genes govern fungal arrest at different stages of the interaction: (i) at the penetration stage within cell wall appositions (papillae) leaving the attacked cell alive (mlo); (ii) within papillae of cells that subsequently undergo a hypersensitive cell death (HR) (Mlg); or (iii) after penetration by a subsequent HR (Mla12), The susceptible parent line Pallas showed a transient O-2(-) generation in penetrated epidermal cells at 18 h after inoculation (hai), whereas epidermal cells of the resistant BCPMla12 produced O-2(-) over a longer time range (by 18 to 36 hai) preceding cell death, No oxidative burst was detected in association with penetration resistance due to effective papillae (BCPMlg and BCPmlo5) although Mlg specified an HR subsequent to fungal arrest, Hence, O-2(-) generation in attacked epidermal cells was a result of fungal penetration of the host cell walls and subsequent contact with the host plasma membrane, and not a requirement for HR elicitation, O-2(-) generation in the mesophyll tissue beneath attacked cells was associated with the response mediated by the genes Mla12 and Mlg. However, only BCPMla12 showed mesophyll cell death, The data indicate that, in barley, O-2(-) accumulation is not a single key determinant of HR in response to a powdery mildew attack.

Harvard Citation style: Hückelhoven, R. and Kogel, K. (1998) Tissue-specific superoxide generation at interaction sites in resistant and susceptible near-isogenic barley lines attacked by the powdery mildew fungus (Erysiphe graminis f. sp. hordei), Molecular Plant-Microbe Interactions, 11(4), pp. 292-300. https://doi.org/10.1094/MPMI.1998.11.4.292

APA Citation style: Hückelhoven, R., & Kogel, K. (1998). Tissue-specific superoxide generation at interaction sites in resistant and susceptible near-isogenic barley lines attacked by the powdery mildew fungus (Erysiphe graminis f. sp. hordei). Molecular Plant-Microbe Interactions. 11(4), 292-300. https://doi.org/10.1094/MPMI.1998.11.4.292