Edinburgh, Scotland, United Kingdom - TAIR
Edinburgh, Scotland, United Kingdom - TAIR
Edinburgh, Scotland, United Kingdom - TAIR
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
A regulated auxin minimum is required for<br />
tissue patterning in Arabidopsis fruit<br />
Local hormone maxima are essential for the development of multicellular<br />
structures and organs. For example, steroid hormones accumulate in specific<br />
cell types of the animal foetus to induce sexual differentiation and concentration<br />
peaks of the plant hormone auxin direct organ initiation and mediate tissue<br />
patterning. Here we show the first example of a regulated local hormone<br />
minimum required during organogenesis. Our results demonstrate that formation<br />
of a local auxin minimum is necessary for specification of the valve margin<br />
separation layer where Arabidopsis fruit opening takes place. Consequently,<br />
ectopic production of auxin, specifically in valve margin cells, leads to a complete<br />
loss of proper cell fate determination. We demonstrate that the valve margin<br />
identity factor INDEHISCENT (IND) is responsible for forming the auxin minimum<br />
by altering the polarity of PIN auxin efflux carriers. IND re-localises PINs by<br />
directly regulating expression of the genes encoding the PINOID kinase and the<br />
close relative, WAG2, which have been shown to direct PIN polarity. We propose<br />
that the simplicity of formation and maintenance make local hormone minima<br />
particularly well-suited to specify a small number of cells such as the stripes at<br />
the valve margins. To our knowledge this is the first report of a regulated<br />
signalling minimum in plants or animals.<br />
84<br />
C33<br />
Thursday 15:15 - 15:30<br />
Plant Growth Regulators<br />
Karim Sorefan1<br />
Thomas Girin1<br />
Sarah Liljegren2<br />
Karin Ljung3<br />
Pedro Robles4<br />
Carlos Galván-Ampudia5<br />
Remko Offringa6<br />
Jiri Friml7<br />
Martin Yanofsky8<br />
Lars Ostergaard1<br />
1John Innes Centre<br />
Norwich<br />
UK<br />
2University of North<br />
Carolina at Chapel Hill<br />
Chapel Hill<br />
USA<br />
3Umeå Plant Science Centre<br />
Umeå<br />
Sweden<br />
4Universidad Miguel<br />
Hernandez<br />
Campus de Elche<br />
Alicante<br />
Spain<br />
5Institute of Biology<br />
Leiden University<br />
Wassenaarseweg AL Leiden<br />
The Netherlands<br />
6 Department of Molecular<br />
and Developmental<br />
Genetics<br />
Institute of Biology<br />
Leiden University<br />
Wassenaarseweg<br />
AL Leiden<br />
The Netherlands<br />
7Department of Plant<br />
Systems Biology<br />
VIB, and Department of<br />
Molecular Genetics<br />
Ghent University<br />
Gent<br />
Belgium<br />
8Section of Cell and<br />
Developmental Biology<br />
University of California at<br />
San Diego<br />
La Jolla<br />
California<br />
USA
Change language