A novel regulatory circuit underlying plant response to canopy shade.
A plant growing in the field has the unique ability to sense the presence of other plants growing near by and adjust its growth rate accordingly. This ability to detect neighbors, which is referred to as shade avoidance response, is mediated by members of the phytochrome family which detect light in the red (R) and far-red (FR) region of the spectrum. Work done by several laboratories has shown that low R/FR provides the signal for shade avoidance response during which the elongation of stem-like organs occurs at the expense of leaf development. However, the mechanism by which the low R/FR signal is transduced to attenuate leaf development has remained largely unknown. In the August issue of Genes and Development, we have shown that low R/FR rapidly and transiently arrests the growth of the leaf primordium. By exploiting mutant analysis in combination with genome wide expression profiling, we have identified a novel regulatory circuit underlying plant response to canopy shade. Together, the data demonstrate that the growth arrest induced by low R/FR depends on auxin-induced cytokinin breakdown in pre-procambial cells of developing primordia. In this addendum, we discuss open questions to be addressed in the future.
Carabelli
Monica
M
Institute of Molecular Biology and Pathology; National Research Council; Rome, Italy.
Possenti
Marco
M
Sessa
Giovanna
G
Ciolfi
Andrea
A
Sassi
Massimiliano
M
Morelli
Giorgio
G
Ruberti
Ida
I
Plant Cell. 1997 Nov;9(11):1963-71
9401121
Plant J. 2003 Jul;35(1):57-70
12834402
Plant Cell. 2006 Jan;18(1):40-54
16361392
Ann Bot. 2005 Aug;96(2):169-75
15894550
Plant Cell. 2004 Jun;16(6):1365-77
15155880
Nature. 2000 Oct 5;407(6804):585-91
11034200
Plant Physiol. 2000 Mar;122(3):621-6
10712524
Nature. 2005 May 26;435(7041):446-51
15917798
Nature. 2005 May 26;435(7041):441-5
15917797
Genes Dev. 2005 Dec 1;19(23):2811-5
16322556
Plant Cell. 2003 Nov;15(11):2532-50
14555694
Trends Plant Sci. 1999 Mar;4(3):97-102
10322540
Development. 1999 Oct;126(19):4235-45
10477292
Trends Plant Sci. 2002 Sep;7(9):399-404
12234731
Plant Cell. 1997 May;9(5):745-57
9165751