title: Characterization of photomorphogenic responses and signaling cascades controlled by phytochrome-A expressed in different tissues.
abstract: The photoreceptor phytochrome A acts as a light-dependent molecular switch and regulates responses initiated by very low fluences of light (VLFR) and high fluences (HIR) of far-red light. PhyA is expressed ubiquitously, but how phyA signaling is orchestrated to regulate photomorphogenesis is poorly understood. To address this issue, we generated transgenic Arabidopsis thaliana phyA-201 mutant lines expressing the biologically active phyA-YFP photoreceptor in different tissues, and analyzed the expression of several reporter genes, including ProHY5:HY5-GFP and Pro35S:CFP-PIF1, and various FR-HIR-dependent physiological responses. We show that phyA action in one tissue is critical and sufficient to regulate flowering time and root growth; control of cotyledon and hypocotyl growth requires simultaneous phyA activity in different tissues; and changes detected in the expression of reporters are not restricted to phyA-containing cells. We conclude that FR-HIR-controlled morphogenesis in Arabidopsis is mediated partly by tissue-specific and partly by intercellular signaling initiated by phyA. Intercellular signaling is critical for many FR-HIR induced responses, yet it appears that phyA modulates the abundance and activity of key regulatory transcription factors in a tissue-autonomous fashion.
authors.affiliation: Faculty of Biology, Institute of Molecular Plant Physiology, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kirchenbauer
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Temesvári krt.62, Szeged, H-6726, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Viczián
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Temesvári krt.62, Szeged, H-6726, Hungary.
authors.forename: Éva
authors.initials: É
authors.lastname: Ádám
authors.affiliation: Institute of Biophysics, Biological Research Centre, Temesvári krt.62, Szeged, H-6726, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Hegedűs
authors.affiliation: Faculty of Biology, Institute of Molecular Plant Physiology, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Klose
authors.affiliation: Faculty of Biology, Institute of Molecular Plant Physiology, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Leppert
authors.affiliation: Faculty of Biology, Institute of Molecular Plant Physiology, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany.|BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, 79104, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hiltbrunner
authors.affiliation: Faculty of Biology, Institute of Molecular Plant Physiology, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kircher
authors.affiliation: Faculty of Biology, Institute of Molecular Plant Physiology, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany.|BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, 79104, Germany.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Schäfer
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Temesvári krt.62, Szeged, H-6726, Hungary.|Institute of Molecular Plant Science, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JH, UK.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Nagy
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D035264:Flowers / Q000502:physiology / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D008027:Light; D058503:Mesophyll Cells / Q000166:cytology / Q000378:metabolism; D009024:Morphogenesis / Q000528:radiation effects*; D009928:Organ Specificity / Q000528:radiation effects; D010641:Phenotype; D018524:Phototropism; D051942:Phytochrome A / Q000378:metabolism*; D054046:Plant Stomata / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified; D059748:Proteolysis / Q000528:radiation effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects*; D014158:Transcription, Genetic / Q000528:radiation effects
chemical_list: D029681:Arabidopsis Proteins; C497973:PHYA protein, Arabidopsis; D051942:Phytochrome A; D011993:Recombinant Fusion Proteins
keywords: Arabidopsis thaliana; photomorphogenesis; phytochrome A; signaling; tissue/cell specificity; transcription