title: Phytochrome control of flowering is temperature sensitive and correlates with expression of the floral integrator FT.
abstract: In Arabidopsis flowering is accelerated by reduced red:far-red (R:FR) ratio which signals the presence of neighbouring vegetation. Hastened flowering is one component of the shade-avoidance syndrome of responses, which alter many aspects of development in response to the threat of potential competition. Of the red/far-red-absorbing photoreceptors it is phyB that plays the most prominent role in shade-avoidance, although other related phytochromes act redundantly with phyB. It is well established that the phyB mutant has a constitutively early flowering phenotype. However, we have shown that the early flowering phenotype of phyB is temperature-dependent. We have established that this temperature-sensitive flowering response defines a pathway that appears to be independent of the autonomous-FLC pathway. Furthermore, we have demonstrated that the phytochromes control the expression of the floral promoter FT. We have also shown that other phyB-controlled responses, including petiole elongation, are not sensitive to the same temperature change. This suggests that discrete pathways control flowering and petiole elongation, components of the shade-avoidance response. This work provides an insight into the phytochrome and temperature interactions that maintain flowering control.
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK. k.j.halliday@bristol.ac.uk
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Halliday
authors.forename: Michael G
authors.initials: MG
authors.lastname: Salter
authors.forename: Elin
authors.initials: E
authors.lastname: Thingnaes
authors.forename: Garry C
authors.initials: GC
authors.lastname: Whitelam
mesh_terms: D001059:Apoproteins / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008027:Light; D009154:Mutation; D010641:Phenotype; D010786:Photoreceptor Cells; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism*; D051939:Phytochrome B; D015398:Signal Transduction; D013696:Temperature; D013997:Time Factors; D014157:Transcription Factors
chemical_list: D001059:Apoproteins; D029681:Arabidopsis Proteins; C418905:FT protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; D014157:Transcription Factors; D010834:Phytochrome; D051939:Phytochrome B; C088754:PHYD protein, Arabidopsis