title: Arabidopsis thaliana plants acclimated to low dose rates of ultraviolet B radiation show specific changes in morphology and gene expression in the absence of stress symptoms.
abstract: Ultraviolet B (UV-B) acclimation comprises complex and poorly understood changes in plant metabolism. The effects of chronic and ecologically relevant UV-B dose rates on Arabidopsis thaliana were determined. The UV-B acclimation process was studied by measuring radiation effects on morphology, physiology, biochemistry and gene expression. Chronic UV-B radiation did not affect photosynthesis or the expression of stress responsive genes, which indicated that the UV-acclimated plants were not stressed. UV-induced morphological changes in acclimated plants included decreased rosette diameter, decreased inflorescence height and increased numbers of flowering stems, indicating that chronic UV-B treatment caused a redistribution rather than a cessation of growth. Gene expression profiling indicated that UV-induced morphogenesis was associated with subtle changes in phytohormone (auxins, brassinosteroids and gibberellins) homeostasis and the cell wall. Based on the comparison of gene expression profiles, it is concluded that acclimation to low, chronic dose rates of UV-B is distinct from that to acute, stress-inducing UV-B dose rates. Hence, UV-B-induced morphogenesis is functionally uncoupled from stress responses.
authors.affiliation: Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Hectors
authors.affiliation: Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Prinsen
authors.affiliation: Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: De Coen
authors.affiliation: Department of Zoology, Ecology and Plant Science, University College Cork, Distillery Field, North Mall, Cork, Ireland.
authors.forename: Marcel A K
authors.initials: MAK
authors.lastname: Jansen
authors.affiliation: Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: Yves
authors.initials: Y
authors.lastname: Guisez
mesh_terms: D000064:Acclimatization; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000528:radiation effects*; D002734:Chlorophyll / Q000096:biosynthesis; D004307:Dose-Response Relationship, Radiation; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D010935:Plant Diseases; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D002734:Chlorophyll