title: Arabidopsis thaliana TERMINAL FLOWER2 is involved in light-controlled signalling during seedling photomorphogenesis.
abstract: Plants respond to changes in the environment by altering their growth pattern. Light is one of the most important environmental cues and affects plants throughout the life cycle. It is perceived by photoreceptors such as phytochromes that absorb light of red and far-red wavelengths and control, for example, seedling de-etiolation, chlorophyll biosynthesis and shade avoidance response. We report that the terminal flower2 (tfl2) mutant, carrying a mutation in the Arabidopsis thaliana HETEROCHROMATIN PROTEIN1 homolog, functions in negative regulation of phytochrome dependent light signalling. tfl2 shows defects in both hypocotyl elongation and shade avoidance response. Double mutant analysis indicates that mutants of the red/far-red light absorbing phytochrome family of plant photoreceptors, phyA and phyB, are epistatic to tfl2 in far-red and red light, respectively. An overlap between genes regulated by light and by auxin has earlier been reported and, in tfl2 plants light-dependent auxin-regulated genes are misexpressed. Further, we show that TFL2 binds to IAA5 and IAA19 suggesting that TFL2 might be involved in regulation of phytochrome-mediated light responses through auxin action.
authors.affiliation: Department of Physiological Botany, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18d, SE-75236 Uppsala, Sweden.
authors.forename: Ana Elisa
authors.initials: AE
authors.lastname: Valdés
authors.forename: Kristina
authors.initials: K
authors.lastname: Rizzardi
authors.forename: Henrik
authors.initials: H
authors.lastname: Johannesson
authors.forename: Alessia
authors.initials: A
authors.lastname: Para
authors.forename: Annika
authors.initials: A
authors.lastname: Sundås-Larsson
authors.forename: Katarina
authors.initials: K
authors.lastname: Landberg
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002734:Chlorophyll / Q000032:analysis; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000254:growth & development; D007210:Indoleacetic Acids / Q000378:metabolism; D008027:Light; D009154:Mutation; D010641:Phenotype; D051942:Phytochrome A / Q000378:metabolism; D051939:Phytochrome B / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D002734:Chlorophyll; D002868:Chromosomal Proteins, Non-Histone; D007210:Indoleacetic Acids; D051942:Phytochrome A; D051939:Phytochrome B; C497973:PHYA protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; C477788:At5g17690 protein, Arabidopsis