title: COP1/SPA ubiquitin ligase complexes repress anthocyanin accumulation under low light and high light conditions.
abstract: In Arabidopsis and many other plant species, anthocyanin pigments accumulate only after light exposure and not in darkness. Excess light of very high fluence rates leads to a further, very strong increase in anthocyanin levels. How excess light is sensed is not well understood. Here, we show that mutations in the key repressor of light signaling, the COP1/SPA complex, cause a strong hyperaccumulation of anthocyanins not only under normal light but also under excess, high light conditions. Hence, normal light signaling via COP1/SPA is required to prevent hyperaccumulation of anthocyanins under these high light conditions. However, since cop1 and spa mutants show a similar high-light responsiveness of anthocyanin accumulation as the wild type it remains to be resolved whether COP1/SPA is directly involved in the high-light response itself.
authors.affiliation: a Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS) ; University of Cologne ; Cologne , Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Maier
authors.forename: Ute
authors.initials: U
authors.lastname: Hoecker
mesh_terms: D000872:Anthocyanins / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D008027:Light; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D029681:Arabidopsis Proteins; D012097:Repressor Proteins; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases
keywords: COP1, constitutive photomorphogenic 1; COP1/SPA; CRY1, cryptochrome 1; HY5, elongated hypocotyl 5; PAP, production of anthocyanin pigment; SPA, supressor of phytochrome A-105; anthocyanin; high light; light; photomorphogenesis; signaling; stress