FLOWERING LOCUS C mediates natural variation in the high-temperature response of the Arabidopsis circadian clock.
Temperature compensation contributes to the accuracy of biological timing by preventing circadian rhythms from running more quickly at high than at low temperatures. We previously identified quantitative trait loci (QTL) with temperature-specific effects on the circadian rhythm of leaf movement, including a QTL linked to the transcription factor FLOWERING LOCUS C (FLC). We have now analyzed FLC alleles in near-isogenic lines and induced mutants to eliminate other candidate genes. We showed that FLC lengthened the circadian period specifically at 27 degrees C, contributing to temperature compensation of the circadian clock. Known upstream regulators of FLC expression in flowering time pathways similarly controlled its circadian effect. We sought to identify downstream targets of FLC regulation in the molecular mechanism of the circadian clock using genome-wide analysis to identify FLC-responsive genes and 3503 transcripts controlled by the circadian clock. A Bayesian clustering method based on Fourier coefficients allowed us to discriminate putative regulatory genes. Among rhythmic FLC-responsive genes, transcripts of the transcription factor LUX ARRHYTHMO (LUX) correlated in peak abundance with the circadian period in flc mutants. Mathematical modeling indicated that the modest change in peak LUX RNA abundance was sufficient to cause the period change due to FLC, providing a molecular target for the crosstalk between flowering time pathways and circadian regulation.
Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3JH United Kingdom.
Kieron D
KD
Edwards
Paul E
PE
Anderson
Anthony
A
Hall
Neeraj S
NS
Salathia
James C W
JC
Locke
James R
JR
Lynn
Martin
M
Straume
James Q
JQ
Smith
Andrew J
AJ
Millar
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002940:Circadian Rhythm / Q000235:genetics*; D016000:Cluster Analysis; D005583:Fourier Analysis; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D023281:Genomics / Q000379:methods; D005838:Genotype; D006358:Hot Temperature; D026161:MADS Domain Proteins / Q000235:genetics / Q000502:physiology*; D008957:Models, Genetic; D009687:Nuclear Proteins / Q000378:metabolism; D040641:Quantitative Trait Loci; D014157:Transcription Factors / Q000378:metabolism
D029681:Arabidopsis Proteins; C480954:EPR1 protein, Arabidopsis; C418902:At5g10140 protein, Arabidopsis; C504848:Lux Arrhythmo protein, Arabidopsis; D026161:MADS Domain Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors