First published online July 19, 2004
Development 131, 1505e (2004)
© The Company of Biologists Limited
Why leaves are flat
Plant leaves are typically flat structures. To produce this shape, the leaf
primordium, as it emerges from the shoot apical meristem, grows perpendicular
to its adaxial-abaxial axis - the equivalent of the dorsal-ventral axis in
animals. Specialised cells then develop on the two surfaces of the leaf. On
p. 3661, Golz and
co-workers report that GRAMINIFOLIA (GRAM) and PROLONGATA (PROL), related
YABBY transcription factors, promote the growth and asymmetry of
Antirrhinum majus leaves. The researchers show that GRAM
expression in the abaxial margins of leaf primordia promotes lateral growth
and abaxial cell fate by excluding adaxial identity. Paradoxically,
GRAM (and its paralogue PROL) also promotes adaxial organ
identity by acting non cell-autonomously. The researchers draw a parallel with
Decapentaplegic signalling, which specifies both dorsal and ventral fates in
Drosophila embryos, and propose that the opposing effects of
GRAM reinforce and maintain the adaxial-abaxial boundary in leaf
primordia.
Related articles in Development:
- GRAMINIFOLIA promotes growth and polarity of Antirrhinum leaves
- John F. Golz, Mario Roccaro, Robert Kuzoff, and Andrew Hudson
Development 2004 131: 3661-3670.
[Abstract]
[Full Text]
