title: Perception of low red:far-red ratio compromises both salicylic acid- and jasmonic acid-dependent pathogen defences in Arabidopsis.
abstract: In dense stands of plants, such as agricultural monocultures, plants are exposed simultaneously to competition for light and other stresses such as pathogen infection. Here, we show that both salicylic acid (SA)-dependent and jasmonic acid (JA)-dependent disease resistance is inhibited by a simultaneously reduced red:far-red light ratio (R:FR), the early warning signal for plant competition. Conversely, SA- and JA-dependent induced defences did not affect shade-avoidance responses to low R:FR. Reduced pathogen resistance by low R:FR was accompanied by a strong reduction in the regulation of JA- and SA-responsive genes. The severe inhibition of SA-responsive transcription in low R:FR appeared to be brought about by the repression of SA-inducible kinases. Phosphorylation of the SA-responsive transcription co-activator NPR1, which is required for full induction of SA-responsive transcription, was indeed reduced and may thus play a role in the suppression of SA-mediated defences by low R:FR-mediated phytochrome inactivation. Our results indicate that foraging for light through the shade-avoidance response is prioritised over plant immune responses when plants are simultaneously challenged with competition and pathogen attack.
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Mieke
authors.initials: M
authors.lastname: de Wit
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Daniel Rutherford Building, Mayfield Rd, Edinburgh, EH9 3JR, UK.
authors.forename: Steven H
authors.initials: SH
authors.lastname: Spoel
authors.affiliation: Theoretical Biology & Bioinformatics, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Gabino F
authors.initials: GF
authors.lastname: Sanchez-Perez
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Charlotte M M
authors.initials: CMM
authors.lastname: Gommers
authors.affiliation: Plant-Microbe Interactions, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Corné M J
authors.initials: CMJ
authors.lastname: Pieterse
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Laurentius A C J
authors.initials: LACJ
authors.lastname: Voesenek
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Ronald
authors.initials: R
authors.lastname: Pierik
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000276:immunology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D020171:Botrytis / Q000472:pathogenicity; D003517:Cyclopentanes / Q000494:pharmacology*; D003624:Darkness; D015870:Gene Expression; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008027:Light; D055537:Light Signal Transduction; D020411:Oligonucleotide Array Sequence Analysis; D054883:Oxylipins / Q000494:pharmacology*; D010766:Phosphorylation; D010834:Phytochrome; D010935:Plant Diseases / Q000276:immunology*; D057865:Plant Immunity; D044224:Pseudomonas syringae / Q000502:physiology; D020156:Salicylic Acid / Q000494:pharmacology*
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; C105496:NPR1 protein, Arabidopsis; D054883:Oxylipins; D010834:Phytochrome; C011006:jasmonic acid; D020156:Salicylic Acid