The overall aerial architecture of flowering plants depends on a group of meristematic cells in the shoot apex. We demonstrate that the Arabidopsis TERMINAL FLOWER 1 gene has a unified effect on the rate of progression of the shoot apex through different developmental phases. In transgenic Arabidopsis plants which ectopically express TERMINAL FLOWER 1, both the vegetative and reproductive phases are greatly extended. As a consequence, these plants exhibit dramatic changes in their overall morphology, producing an enlarged vegetative rosette of leaves, followed by a highly branched inflorescence which eventually forms normal flowers. Activity of the floral meristem identity genes LEAFY and APETALA 1 is not directly inhibited by TERMINAL FLOWER 1, but their upregulation is markedly delayed compared to wild-type controls. These phenotypic and molecular effects complement those observed in the tfl1 mutant, where all phases are shortened. The results suggest that TERMINAL FLOWER 1 participates in a common mechanism underlying major shoot apical phase transitions, rather than there being unrelated mechanisms which regulate each specific transition during the life cycle.

Alvarez
J.
,
Guli
C. L.
,
Yu
X.-H.
,
Smyth
D. R.
(
1992
)
TERMINAL FLOWER: a gene affecting inflorescence development in Arabidopsis thaliana.
Plant J
2
,
103
116
Bowman
J. L.
,
Alvarez
J.
,
Weigel
D.
,
Meyerowitz
E. M.
,
Smyth
D. R.
(
1993
)
Control of flower development in Arabidopsis thaliana by APETALA1 and interacting genes.
Development
119
,
721
743
Bradley
D.
,
Carpenter
R.
,
Copsey
L.
,
Vincent
C.
,
Rothstein
S.
,
Coen
E.
(
1996
)
Control of inflorescence architecture in Antirrhinum.
Nature
379
,
791
797
Bradley
D.
,
Ratcliffe
O.
,
Vincent
C.
,
Carpenter
R.
,
Coen
E.
(
1997
)
Inflorescence commitment and architecture in Arabidopsis.
Science
275
,
80
83
Coen
E. S.
,
Romero
J. M.
,
Doyle
S.
,
Elliot
R.
,
Murphy
G.
,
Carpenter
R.
(
1990
)
Floricaula: a homeotic gene required for flower development in Antirrhinum majus.
Cell
63
,
1311
1322
Forsburg
S.
,
Nurse
P.
(
1991
)
Cell cycle regulation in yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe.
Annu. Rev. Cell Biol
7
,
227
256
Green
P. B.
,
Linstead
P.
(
1990
)
A procedure for SEM analysis of complex shoot structures applied to the inflorescence of snapdragon (Antirrhinum).
Protoplasma
158
,
33
38
Gustafson-Brown
C.
,
Savidge
B.
,
Yanofsky
M. F.
(
1994
)
Regulation of the floral homeotic gene APETALA1.
Cell
76
,
131
143
Hempel
F. D.
,
Feldman
L. J.
(
1994
)
Bidirectional inflorescence development in Arabidopsis thaliana: Acropetal initiation of flowers and basipetal initiation of paraclades.
Planta
192
,
276
286
Hempel
F. D.
,
Weigel
D.
,
Mandel
M. A.
,
Ditta
G.
,
Zambryski
P. C.
,
Feldman
L. J.
,
Yanofsky
M. F.
(
1997
)
Floral determination and expression of floral regulatory genes in Arabidopis.
Development
124
,
3845
3853
Jones
J. D. G.
,
Shlumukov
L.
,
Harland
F.
,
English
J.
,
Scofield
S. R.
,
Bishop
G. J.
,
Harrison
K.
(
1992
)
Effective vectors for transformation, expression of heterologous genes, and assaying transposon excision in transgenic plants.
Transgenic Research
1
,
285
297
Koornneef
M.
,
Hanhart
C. J.
,
van der Veen
J. H.
(
1991
)
A genetic and physiological analysis of late flowering mutants in Arabidopsis thaliana.
Mol. Gen. Genet
229
,
57
66
Mandel
M. A.
,
Gustafson-Brown
C.
,
Savidge
B.
,
Yanofsky
M. F.
(
1992
)
Molecular characterization of the Arabidopsis floral homeotic gene APETALA1.
Nature
360
,
273
277
Mandel
M. A.
,
Yanofsky
M. F.
(
1995
)
A gene triggering flower development in Arabidopsis.
Nature
377
,
522
524
Odell
J. T.
,
Nagy
F.
,
Chua
N.-H.
(
1985
)
Identification of DNA sequences required for the activity of the cauliflower mosaic virus 35S promoter.
Nature
313
,
810
812
Ohshima
S.
,
Murata
M.
,
Sakamoto
W.
,
Ogura
Y.
,
Motoyoshi
F.
(
1997
)
Cloning and analysis of the Arabidopsis gene TERMINAL FLOWER 1.
Mol. Gen. Genet
254
,
186
194
Poethig
R. S.
(
1990
)
Phase change and the regulation of shoot morphogenesis in plants.
Science
250
,
923
929
Putterill
J.
,
Robson
F.
,
Lee
K.
,
Simon
R.
,
Coupland
G.
(
1995
)
The CONSTANS gene of Arabidopsis promotes flowering and encodes aprotein showing similarites to zinc finger transcription factors.
Cell
80
,
847
857
Ray
A.
,
Lang
J. D.
,
Golden
T.
,
Ray
S.
(
1996
)
SHORT INTEGUMENT (SIN1), a gene required for ovule development in Arabidopsis also controls flowering time.
Development
122
,
2631
2638
Ruiz-Garcia
L.
,
Madueno
F.
,
Wilkinson
M.
,
Haughn
G.
,
Salinas
J.
,
Martinez-Zapater
J. M.
(
1997
)
Different roles of flowering time genes in the activation of floral initiation genes in Arabidopsis.
Plant Cell
9
,
1921
1934
Schultz
E. A.
,
Haughn
G.W.
(
1991
)
LEAFY, a homeotic gene that regulates inflorescence development in Arabidopsis.
Plant Cell
3
,
771
781
Shannon
S.
,
Meeks-Wagner
D. R.
(
1991
)
A mutation in the Arabidopsis TFL1 gene affects inflorescence meristem development.
Plant Cell
3
,
877
892
Shannon
S.
,
Meeks-Wagner
D. R.
(
1993
)
Genetic interactions that regulate inflorescence development in Arabidopsis.
Plant Cell
5
,
639
655
Simon
R.
,
Igeno
M. I.
,
Coupland
G.
(
1996
)
Activation of floral meristem identity genes in Arabidopsis.
Nature
384
,
59
62
Telfer
A.
,
Bollman
M.
,
Poethig
R. S.
(
1997
)
Phase change and the regulation of trichome distribution in Arabidopsis thaliana.
Development
124
,
645
654
Valvekans
D.
,
van Montagu
M.
,
Van Lijebettens
M.
(
1988
)
Agrobacteriumtumifaciens mediated transformation of Arabidopsis thaliana root explants by kanamycin selection.
Proc. Natn. Acad. Sci.USA
85
,
5536
5540
Weigel
D.
,
Alvarez
J.
,
Smyth
D. R.
,
Yanofsky
M. F.
,
Meyerowitz
E. M.
(
1992
)
LEAFY controls floral meristem identity in Arabidopsis.
Cell
69
,
843
859
Weigel
D.
,
Nilsson
O.
(
1995
)
A developmental switch sufficient for flower initiation in diverse plants.
Nature
377
,
495
500
This content is only available via PDF.