title: Role of Arabidopsis UV RESISTANCE LOCUS 8 in plant growth reduction under osmotic stress and low levels of UV-B.
abstract: In high-light environments, plants are exposed to different types of stresses, such as an excess of UV-B, but also drought stress which triggers a common morphogenic adaptive response resulting in a general reduction of plant growth. Here, we report that the Arabidopsis thaliana UV RESISTANCE LOCUS 8 (UVR8) gene, a known regulator of the UV-B morphogenic response, was able to complement a Saccharomyces cerevisiae osmo-sensitive mutant and its expression was induced after osmotic or salt stress in Arabidopsis plants. Under low levels of UV-B, plants overexpressing UVR8 are dwarfed with a reduced root development and accumulate more flavonoids compared to control plants. The growth defects are mainly due to the inhibition of cell expansion. The growth inhibition triggered by UVR8 overexpression in plants under low levels of UV-B was exacerbated by mannitol-induced osmotic stress, but it was not significantly affected by ionic stress. In contrast, uvr8-6 mutant plants do not differ from wild-type plants under standard conditions, but they show an increased shoot growth under high-salt stress. Our data suggest that UVR8-mediated accumulation of flavonoid and possibly changes in auxin homeostasis are the underlying mechanism of the observed growth phenotypes and that UVR8 might have an important role for integrating plant growth and stress signals.
authors.affiliation: Department of Pharmacy, University of Salerno, Fisciano, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Fasano
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gonzalez
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tosco
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Dal Piaz
authors.forename: Teresa
authors.initials: T
authors.lastname: Docimo
authors.forename: Ramon
authors.initials: R
authors.lastname: Serrano
authors.forename: Stefania
authors.initials: S
authors.lastname: Grillo
authors.forename: Antonella
authors.initials: A
authors.lastname: Leone
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
mesh_terms: D000217:Acyltransferases / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D005419:Flavonoids / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics; D009154:Mutation; D009997:Osmotic Pressure; D010641:Phenotype; D010749:Phosphoprotein Phosphatases / Q000235:genetics; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D012492:Salts / Q000494:pharmacology; D014466:Ultraviolet Rays; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D002868:Chromosomal Proteins, Non-Histone; D005419:Flavonoids; D007210:Indoleacetic Acids; D029701:Saccharomyces cerevisiae Proteins; D012492:Salts; C525052:Uvr8 protein, Arabidopsis; D000217:Acyltransferases; C020141:flavanone synthetase; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; C075119:PPZ1 protein, S cerevisiae; D010749:Phosphoprotein Phosphatases
keywords: auxin.; cell expansion; flavonoid; growth reduction; osmotic stress