Resetting of FLOWERING LOCUS C expression after epigenetic repression by vernalization.
The epigenetic repression of FLOWERING LOCUS C (FLC) in winter-annual ecotypes of Arabidopsis by prolonged cold ensures that plants flower in spring and not during winter. Resetting of the FLC expression level in progeny is an important step in the life cycle of the plant. We show that both the paternally derived and the maternally derived FLC:GUS genes are reset to activity but that the timing of their first expression differs. The paternal FLC:GUS gene in vernalized plants is expressed in the male reproductive organs, the anthers, in both somatic tissue and in the sporogenous pollen mother cells, but there is no expression in mature pollen. In the progeny generation, the paternally derived FLC:GUS gene is expressed in the single-celled zygote (fertilized egg cell) and through embryo development, but not in the fertilized central cell, which generates the endosperm of the progeny seed. FLC:GUS is not expressed during female gametogenesis, with the maternally derived FLC:GUS being first expressed in the early multicellular embryo. We show that FLC activity during late embryo development is a prerequisite for the repressive action of FLC on flowering.
Sheldon
Candice C
CC
Commonwealth Scientific and Industrial Research Organisation, Plant Industry, G.P.O. Box 1600, Canberra ACT 2601, Australia. candice.sheldon@csiro.au
Hills
Melissa J
MJ
Lister
Clare
C
Dean
Caroline
C
Dennis
Elizabeth S
ES
Peacock
W James
WJ
D017360:Arabidopsis / Q000196:embryology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000235:genetics*; D012639:Seeds / Q000254:growth & development
D029681:Arabidopsis Proteins; C418902:At5g10140 protein, Arabidopsis; D026161:MADS Domain Proteins