Show simple item record Luis Alejandro Jose en_US Sylvain en_US Madhav en_US Alison Helen en_US Joe en_US Emma Jane en_US Caron Louise en_US Istvan en_US Stefan en_US Howard en_US Helen Joan en_US 2011-06-07T08:44:31Z 2011-06-07T08:44:31Z 2010-08-05 en_US
dc.identifier en_US
dc.identifier.citation Mur , L A J , Aubry , S , Mondhe , M , Kingston-Smith , A H , Gallagher , J , Timms-Taravella , E J , James , C L , Papp , I , Hörtensteiner , S , Thomas , H & Ougham , H J 2010 , ' Accumulation of chlorophyll catabolites photosensitizes the hypersensitive response elicited by Pseudomonas syringae in Arabidopsis ' New Phytologist , vol 188 , no. 1 , pp. 161-174 . , 10.1111/j.1469-8137.2010.03377.x en_US
dc.identifier.other PURE: 163862 en_US
dc.identifier.other dspace: 2160/6947 en_US
dc.description.abstract The staygreen (SGR) gene encodes a chloroplast-targeted protein which promotes chlorophyll degradation via disruption of light-harvesting complexes (LHCs). Over-expression of SGR in Arabidopsis (SGR-OX) in a Columbia-0 (Col-0) background caused spontaneous necrotic flecking. To relate this to the hypersensitive response (HR), Col-0, SGR-OX and RNAi SGR (SGRi) lines were challenged with Pseudomonas syringae pv tomato (Pst) encoding the avirulence gene avrRpm1. Increased and decreased SGR expression, respectively, accelerated and suppressed the kinetics of HR-cell death. In Col-0, SGR transcript increased at 6 h after inoculation (hai) when tissue electrolyte leakage indicated the initiation of cell death. Excitation of the chlorophyll catabolite pheophorbide (Pheide) leads to the formation of toxic singlet oxygen (1O2). Pheide was first detected at 6 hai with Pst avrRpm1 and was linked to 1O2 generation and correlated with reduced Pheide a oxygenase (PaO) protein concentrations. The maximum quantum efficiency of photosystem II (Fv/Fm), quantum yield of electron transfer at photosystem II (φPSII), and photochemical quenching (qP) decreased at 6 hai in Col-0 but not in SGRi. Disruption of photosynthetic electron flow will cause light-dependent H2O2 generation at 6 hai. We conclude that disruption of LHCs, possibly influenced by SGR, and absence of PaO produce phototoxic chlorophyll catabolites and oxidative stress leading to the HR. en_US
dc.format.extent 14 en_US
dc.relation.ispartof New Phytologist en_US
dc.subject Arabidopsis en_US
dc.subject death en_US
dc.subject hypersensitive response en_US
dc.subject light-dependent pheophorbide en_US
dc.subject photosynthesis en_US
dc.subject Pseudomonas syringae en_US
dc.subject singlet oxygen (1O2) en_US
dc.subject staygreen en_US
dc.title Accumulation of chlorophyll catabolites photosensitizes the hypersensitive response elicited by Pseudomonas syringae in Arabidopsis en_US
dc.contributor.pbl Institute of Biological, Environmental and Rural Sciences en_US

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