title: Are solar UV-B- and UV-A-dependent gene expression and metabolite accumulation in Arabidopsis mediated by the stress response regulator RADICAL-INDUCED CELL DEATH1?
abstract: Wavelengths in the ultraviolet (UV) region of the solar spectrum, UV-B (280-315 nm) and UV-A (315-400 nm), are key environmental signals modifying several aspects of plant physiology. Despite significant advances in the understanding of plant responses to UV-B and the identification of signalling components involved, there is limited information on the molecular mechanisms that control UV-B signalling in plants under natural sunlight. Here, we aimed to corroborate the previous suggested role for RADICAL-INDUCED CELL DEATH1 (RCD1) in UV-B signalling under full spectrum sunlight. Wild-type Arabidopsis thaliana and the rcd1-1 mutant were used in an experimental design outdoors where UV-B and UV-A irradiances were manipulated using plastic films, and gene expression, PYRIDOXINE BIOSYNTHESIS1 (PDX1) accumulation and metabolite profiles were analysed in the leaves. At the level of transcription, RCD1 was not directly involved in the solar UV-B regulation of genes with functions in UV acclimation, hormone signalling and stress-related markers. Furthermore, RCD1 had no role on PDX1 accumulation but modulated the UV-B induction of flavonoid accumulation in leaves of Arabidopsis exposed to solar UV. We conclude that RCD1 does not play an active role in UV-B signalling but rather modulates UV-B responses under full spectrum sunlight.
authors.affiliation: Division of Plant Biology, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland; School of Chemical Technology, Department of Forest Products Technology, Aalto University, FI-00076, Aalto, Finland.
authors.forename: Luis O
authors.initials: LO
authors.lastname: Morales
authors.forename: Mikael
authors.initials: M
authors.lastname: Brosché
authors.forename: Julia P
authors.initials: JP
authors.lastname: Vainonen
authors.forename: Nina
authors.initials: N
authors.lastname: Sipari
authors.forename: Anders V
authors.initials: AV
authors.lastname: Lindfors
authors.forename: Åke
authors.initials: Å
authors.lastname: Strid
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Aphalo
mesh_terms: D000064:Acclimatization; D017360:Arabidopsis / Q000378:metabolism* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D019759:Carbon-Nitrogen Lyases; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D019884:Nitrogenous Group Transferases / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D010636:Phenols / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D029681:Arabidopsis Proteins; D009687:Nuclear Proteins; D010636:Phenols; C492758:RCD1 protein, Arabidopsis; D019884:Nitrogenous Group Transferases; D019759:Carbon-Nitrogen Lyases; C505161:At2g38230 protein, Arabidopsis
keywords: RCD1; UV acclimation; flavonoids; signalling; solar UV; stress