Edinburgh, Scotland, United Kingdom - TAIR

Natural variation in Arabidopsis vernalization
response
Plants are excellent systems in which to dissect the molecular basis of
adaptation. Variation in flowering time is a key factor in adaptation as flowering
in favourable conditions is so important for reproductive success. We are
analysing vernalization, the acceleration of flowering by prolonged cold, and its
role in adaptation. In Arabidopsis vernalization involves the cold-induced
repression and epigenetic silencing of the floral repressor FLOWERING LOCUS
C (FLC). We are dissecting the mechanism of this cold-induced Polycombmediated
epigenetic silencing and will present our current understanding of the
three main phases of vernalization - the triggering of FLC transcriptional
repression by prolonged cold; the nucleation and epigenetic stability of chromatin
changes at FLC; and the spreading of the silencing signal. This mechanistic
understanding is being linked with population and ecological genetic analysis in
Arabidopsis accessions from different parts of the world. Our analysis so far
suggests that molecular variation at FLC itself can contribute to variation in
vernalization response. It appears that this variation has arisen independently in
different accessions and we are now determining which phase of vernalization
is affected for each accession and the responsible cis polymorphism. We are
also analysing the distribution of the different alleles within Arabidopsis
populations and monitoring individual populations at three ecologically distinct
sites in Sweden in order to fully understand the evolution of this adaptive trait.
39
L14
Friday 09:30 - 10:00
Natural Variation
Vincent Coustham1
Peijin Li1
Clare Lister1
Svante Holm2
Magnus Nordborg3
Caroline Dean1
1John Innes Centre
Norwich
Norfolk
UK
2University of
Mid-Sweden
3University of Southern
California
USA