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Research article - Peer-reviewed, 2008

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

Mühlenbock, Per; Szechyńska-Hebda, Magdalena; Płaszczyca, Marian; Baudo, Marcela; Mullineaux, Philip M.; Parker, Jane E.; Karpińska, Barbara; Karpiński, Stanisław


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 (lsd1) 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.

Published in

Plant Cell
2008, volume: 20, number: 9, pages: 2339-2356

Authors' information

Mühlenbock, Per
Stockholm University
Szechyńska-Hebda, Magdalena
Stockholm University
Płaszczyca, Marian
Stockholm University
Baudo, Marcela
Stockholm University
Mullineaux, Philip M.
University of Essex
Parker, Jane E.
Max Planck Institute for Plant Breeding Research
Karpińska, Barbara
Södertörn University
Karpiński, Stanisław
Warsaw University of Life Sciences

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