title: Cool night-time temperatures induce the expression of CONSTANS and FLOWERING LOCUS T to regulate flowering in Arabidopsis.
abstract: Day length and ambient temperature are major stimuli controlling flowering time. To understand flowering mechanisms in more natural conditions, we explored the effect of daily light and temperature changes on Arabidopsis thaliana. Seedlings were exposed to different day/night temperature and day-length treatments to assess expression changes in flowering genes. Cooler temperature treatments increased CONSTANS (CO) transcript levels at night. Night-time CO induction was diminished in flowering bhlh (fbh)-quadruple mutants. FLOWERING LOCUS T (FT) transcript levels were reduced at dusk, but increased at the end of cooler nights. The dusk suppression, which was alleviated in short vegetative phase (svp) mutants, occurred particularly in younger seedlings, whereas the increase during the night continued over 2 wk. Cooler temperature treatments altered the levels of FLOWERING LOCUS M-β (FLM-β) and FLM-δ splice variants. FT levels correlated strongly with flowering time across treatments. Day/night temperature changes modulate photoperiodic flowering by changing FT accumulation patterns. Cooler night-time temperatures enhance FLOWERING BHLH (FBH)-dependent induction of CO and consequently increase CO protein. When plants are young, cooler temperatures suppress FT at dusk through SHORT VEGETATIVE PHASE (SVP) function, perhaps to suppress precocious flowering. Our results suggest day length and diurnal temperature changes combine to modulate FT and flowering time.
authors: Department of Biology, University of Washington, Seattle, WA, 98195-1800, USA.
authors: Hannah A
authors: HA
authors: Kinmonth-Schultz
authors: Department of Biology, University of Washington, Seattle, WA, 98195-1800, USA.
authors: Xinran
authors: X
authors: Tong
authors: Department of Biology, University of Washington, Seattle, WA, 98195-1800, USA.
authors: Jae
authors: J
authors: Lee
authors: Department of Biology, University of Washington, Seattle, WA, 98195-1800, USA.|Department of Life Sciences, Ajou University, Suwon, 443-749, Korea.
authors: Young Hun
authors: YH
authors: Song
authors: Department of Biology, University of Washington, Seattle, WA, 98195-1800, USA.
authors: Shogo
authors: S
authors: Ito
authors: School of Environmental and Forest Sciences, University of Washington, Seattle, WA, 98195-2100, USA.
authors: Soo-Hyung
authors: SH
authors: Kim
authors: Department of Biology, University of Washington, Seattle, WA, 98195-1800, USA.
authors: Takato
authors: T
authors: Imaizumi
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017440:Photoperiod; D030821:Plants, Genetically Modified; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; C418905:FT protein, Arabidopsis; D014157:Transcription Factors
keywords: Arabidopsis thaliana; CONSTANS; FLOWERING LOCUS T; ambient temperature; flowering time; photoperiod; signal integration