Chloroplast Signaling and LESION SIMULATING DISEASE1 Regulate Crosstalk between Light Acclimation and Immunity in Arabidopsis

• Published in: The Plant cell Vol. 20; no. 9; pp. 2339 - 2356
• Main Authors: Mühlenbock, Per, Szechyńska-Hebda, Magdalena, Płaszczyca, Marian, Baudo, Marcela, Mullineaux, Philip M., Parker, Jane E., Karpińska, Barbara, Karpiński, Stanisław
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01.09.2008
• Subjects: 1-aminocyclopropane-1-carboxylic acid; Acclimatization; Apoptosis; Arabidopsis - genetics; Arabidopsis - immunology; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; ascorbate-peroxidase-2 expression; Carboxylic Ester Hydrolases - genetics; Carboxylic Ester Hydrolases - metabolism; Cell death; Chloroplasts; Chloroplasts - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; ethylene biosynthesis; excess excitation-energy; Gene expression regulation; Gene Expression Regulation, Plant - radiation effects; gene-expression; hydrogen-peroxide; Infections; Leaves; Lesions; Light; Models, Biological; Mortality; NATURAL SCIENCES; NATURVETENSKAP; Oxidation-Reduction; Pathogens; Peroxidases - genetics; Peroxidases - metabolism; photooxidative stress; Plant cells; Plants; Plastoquinone - metabolism; programmed cell-death; reactive oxygen; Reactive Oxygen Species - metabolism; Receptors, Cell Surface - genetics; Receptors, Cell Surface - metabolism; Reverse Transcriptase Polymerase Chain Reaction; salicylic-acid; Signal Transduction - genetics; Signal Transduction - physiology; Signal Transduction - radiation effects; Stomatal conductance; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 1040-4651; 1532-298X; 1532-298X
• DOI: 10.1105/tpc.108.059618

Plants are simultaneously exposed to abiotic and biotic hazards. Here, we show that local and systemic acclimation in Arabidopsis thaliana leaves in response to excess excitation energy (EEE) is associated with cell death and is regulated by specific redox changes of the plastoquinone (PQ) pool. These redox changes cause a rapid decrease of stomatal conductance, global induction of ASCORBATE PEROXIDASE2 and PATHOGEN RESISTANCE1, and increased production of reactive oxygen species (ROS) and ethylene that signals through ETHYLENE INSENSITIVE2 (EIN2). We provide evidence that multiple hormonal/ROS signaling pathways regulate the plant's response to EEE and that EEE stimulates systemic acquired resistance and basal defenses to virulent biotrophic bacteria. In the Arabidopsis LESION SIMULATING DISEASE1 (Isd1) null mutant that is deregulated for EEE acclimation responses, propagation of EEE-induced programmed cell death depends on the plant defense regulators ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) and PHYTOALEXIN DEFICIENT4 (PAD4). We find that EDS1 and PAD4 operate upstream of ethylene and ROS production in the EEE response. The data suggest that the balanced activities of LSD1, EDS1, PAD4, and EIN2 regulate signaling of programmed cell death, light acclimation, and holistic defense responses that are initiated, at least in part, by redox changes of the PQ pool.