Quantitative effects of vernalization on FLC and SOC1 expression.
Prolonged exposure to cold results in early flowering in Arabidopsis winter annual ecotypes, with longer exposures resulting in a greater promotion of flowering than shorter exposures. The promotion of flowering is mediated through an epigenetic down-regulation of the floral repressor FLOWERING LOCUS C (FLC). We present results that provide an insight into the quantitative regulation of FLC by vernalization. Analysis of the effect of seed or plant cold treatment on FLC expression indicates that the time-dependent nature of vernalization on FLC expression is mediated through the extent of the initial repression of FLC and not by affecting the ability to maintain the repressed state. In the over-expression mutant flc-11, the time-dependent repression of FLC correlates with the proportional deacetylation of histone H3. Our results indicate that sequences within intron 1 and the activities of both VERNALIZATION1 (VRN1) and VERNALIZATION2 (VRN2) are required for efficient establishment of FLC repression; however, VRN1 and VRN2 are not required for maintenance of the repressed state during growth after the cold exposure. SUPPRESSOR OF OVER-EXPRESSION OF CO 1 (SOC1), a downstream target of FLC, is quantitatively induced by vernalization in a reciprocal manner to FLC. In addition, we show that SOC1 undergoes an acute induction by both short and long cold exposures.
Sheldon
Candice C
CC
Commonwealth Scientific and Industrial Research Organization, Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia. candice.sheldon@csiro.au
Finnegan
E Jean
EJ
Dennis
Elizabeth S
ES
Peacock
W James
WJ
D000107:Acetylation; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D006657:Histones / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
C419046:AGL20 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C418902:At5g10140 protein, Arabidopsis; D006657:Histones; D026161:MADS Domain Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C036483:T-DNA; C461388:VRN1 protein, Arabidopsis; C442836:VRN2 protein, Arabidopsis