title: Singlet oxygen-mediated and EXECUTER-dependent signalling and acclimation of Arabidopsis thaliana exposed to light stress.
abstract: Plants respond to environmental changes by acclimation that activates defence mechanisms and enhances the plant's resistance against a subsequent more severe stress. Chloroplasts play an important role as a sensor of environmental stress factors that interfere with the photosynthetic electron transport and enhance the production of reactive oxygen species (ROS). One of these ROS, singlet oxygen ((1)O2), activates a signalling pathway within chloroplasts that depends on the two plastid-localized proteins EXECUTER 1 and 2. Moderate light stress induces acclimation protecting photosynthetic membranes against a subsequent more severe high light stress and at the same time activates (1)O2-mediated and EXECUTER-dependent signalling. Pre-treatment of Arabidopsis seedlings with moderate light stress confers cross-protection against a virulent Pseudomonas syringae strain. While non-pre-acclimated seedlings are highly susceptible to the pathogen regardless of whether (1)O2- and EXECUTER-dependent signalling is active or not, pre-stressed acclimated seedlings without this signalling pathway lose part of their pathogen resistance. These results implicate (1)O2- and EXECUTER-dependent signalling in inducing acclimation but suggest also a contribution by other yet unknown signalling pathways during this response of plants to light stress.
authors.affiliation: Boyce Thompson Institute for Plant Research, , Ithaca, NY 14853-1801, USA.
authors.forename: Shengrui
authors.initials: S
authors.lastname: Zhang
authors.forename: Klaus
authors.initials: K
authors.lastname: Apel
authors.forename: Chanhong
authors.initials: C
authors.lastname: Kim
mesh_terms: D000064:Acclimatization / Q000276:immunology*; D017360:Arabidopsis / Q000276:immunology* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000378:metabolism*; D060365:Chloroplast Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000276:immunology; D008027:Light; D044224:Pseudomonas syringae / Q000276:immunology; D036226:Seedlings / Q000276:immunology / Q000382:microbiology; D015398:Signal Transduction / Q000276:immunology*; D026082:Singlet Oxygen / Q000378:metabolism*; D013312:Stress, Physiological / Q000276:immunology*
chemical_list: D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; C521350:EXECUTER1 protein, Arabidopsis; D026082:Singlet Oxygen
keywords: Arabidopsis; Pseudomonas syringae; acclimation; cross-protection; light stress; singlet oxygen signalling