PT - JOURNAL ARTICLE AU - Piffanelli, Pietro AU - Zhou, Fasong AU - Casais, Catarina AU - Orme, James AU - Jarosch, Birgit AU - Schaffrath, Ulrich AU - Collins, Nicholas C. AU - Panstruga, Ralph AU - Schulze-Lefert, Paul TI - The Barley MLO Modulator of Defense and Cell Death Is Responsive to Biotic and Abiotic Stress Stimuli AID - 10.1104/pp.010954 DP - 2002 Jul 01 TA - Plant Physiology PG - 1076--1085 VI - 129 IP - 3 4099 - http://www.plantphysiol.org/content/129/3/1076.short 4100 - http://www.plantphysiol.org/content/129/3/1076.full SO - Plant Physiol.2002 Jul 01; 129 AB - Lack of the barley (Hordeum vulgare) seven-transmembrane domain MLO protein confers resistance against the fungal pathogen Blumeria graminis f. sp.hordei (Bgh). To broaden the basis for MLO structure/function studies, we sequenced additionalmlo resistance alleles, two of which confer only partial resistance. Wild-type MLO dampens the cell wall-restricted hydrogen peroxide burst at points of attempted fungal penetration of the epidermal cell wall, and in subtending mesophyll cells, it suppresses a second oxidative burst and cell death. Although theBgh-induced cell death in mlo plants is spatially and temporally separated from resistance, we show that the two processes are linked. Uninoculated mutant mlo plants exhibit spontaneous mesophyll cell death that appears to be part of accelerated leaf senescence. Mlo transcript abundance increases in response to Bgh, rice (Oryza sativa) blast, wounding, paraquat treatment, a wheat powdery mildew-derived carbohydrate elicitor, and during leaf senescence. This suggests a broad involvement of Mlo in cell death protection and in responses to biotic and abiotic stresses.