The continuous growth of the plant embryo is interrupted during the seed maturation processes which results in a dormant seed. The embryo continues development after germination when it grows into a seedling. The embryo growth phase starts after morphogenesis and ends when the embryo fills the seed sac. Very little is known about the processes regulating this phase. We describe mutants that affect embryo growth in two sequential developmental stages. Firstly, embryo growth arrest is regulated by the FUS3/LEC type genes, as mutations in these genes cause a continuation of growth in immature embryos. Secondly, a later stage of embryo dormancy is regulated by ABI3 and abscisic acid; abi3 and aba1 mutants exhibit premature germination only after embryos mature. Mutations affecting both developmental stages result in an additive phenotype and double mutants are highly viviparous. Embryo growth arrest is regulated by cell division activities in both the embryo and the endosperm, which are gradually switched off at the mature embryo stage. In the fus3/lec mutants, however, cell division in both the embryo and endosperm is not arrested, but rather is prolonged throughout seed maturation. Furthermore ectopic cell division occurs in seedlings. Our results indicate that seed dormancy is secured via at least two sequential developmental processes: embryo growth arrest, which is regulated by cell division and embryo dormancy.

Reference

Aarts
M. G.
,
Corzaan
P.
,
Stiekema
W. J.
,
Pereira
A.
(
1995
)
A two-element Enhancer-Inhibitor transposon system in Arabidopsis thaliana.
Mol. Gen. Genet
247
,
555
564
Baumlein
H.
,
Misera
S.
,
Luerssen
H.
,
Kolle
K.
,
Horstmann
C.
,
Wobus
U.
,
Muller
A. J.
(
1994
)
The FUS3 gene of Arabidopsis thaliana is a regulator of gene expression during late embryogenesis.
Plant J
6
,
379
387
Colon-Carmona
A.
,
You
R.
,
Haimovitch-Gal
T.
,
Doerner
P.
(
1999
)
Spatio-temporal analysis of mitotic activity with a labile cyclin-GUS fusion protein.
Plant J
20
,
503
8
de Castro
R. D.
,
Zheng
X.
,
Bergervoet
J. H. W.
,
de Vos
R. C. H.
,
Bino
R. J.
(
1995
)
-tubulin accumulation and DNA replication in imbibing tomato seeds.
Plant Physiol
109
,
499
504
Debeaujon
I.
,
Koornneef
M.
(
2000
)
Gibberellin requirement for Arabidopsis seed germination is determined both by testa characteristics and embryonic abscisic acid.
Plant Physiol
122
,
415
24
Debeaujon
I.
,
Leon-Kloosterziel
K. M.
,
Koornneef
M.
(
2000
)
Influence of the testa on seed dormancy, germination, and longevity in Arabidopsis.
Plant Physiol
122
,
403
14
Focks
N.
,
Benning
C.
(
1998
)
wrinkled1: A novel, low-seed-oil mutant of Arabidopsis with a deficiency in the seed-specific regulation of carbohydrate metabolism.
Plant Physiol
118
,
91
101
Goldberg
R. B.
,
de Paiva
G.
,
Yadegari
R.
(
1994
)
Plant embryogenesis: Zygote to seed.
Science
266
,
605
614
Karssen
C. M.
,
Brinkhorst-van der Swan
D. C. L.
,
Breekland
A. E.
,
Koornneef
M.
(
1983
).
Induction of dormancy during seed development by endogenous abscisic acid deficient genotypes of Arabidopsis thaliana (L.) Heynh.
Planta
157
,
158
165
Keith
K.
,
Karnl
M.
,
Dengler
N. G.
,
McCourt
P.
(
1994
)
fusca 3: A heterochronic mutation affecting late embryo development in Arabidopsis.
Plant Cell
6
,
589
600
Kerstetter
R. A.
,
Poethig
R. S.
(
1998
)
The specification of leaf identity during shoot development.
Annu. Rev. Cell Dev. Biol
14
,
373
398
Koornneef
M.
,
van der Veen
J. H.
(
1980
).
Induction and analysis ofgibberellin sensitive mutants in Arabidopsis thaliana (L.)
Heynh. Theor. Appl. Genet
58
,
257
263
Lauber
M. H.
,
Waizenegger
I.
,
Steinmann
T.
,
Schwarz
H.
,
Mayer
U.
,
Hwang
I.
,
Lukowitz
W.
,
Jurgens
G.
(
1997
)
The Arabidopsis KNOLLE protein is a cytokinesis-specific syntaxin.
J. Cell Biol
139
,
1485
1493
Leon-Kloosterziel
K. M.
,
van de Bunt
G. A.
,
Zeevaart
J. A. D.
,
Koornneef
M.
(
1996
)
Arabidopsis mutants with a reduced seed dormancy.
Plant Physiol
110
,
233
240
Lotan
T.
,
Ohto
M.
,
Yee
K. M.
,
West
M. A.
,
Lo
R.
,
Kwong
R. W.
,
Yamagishi
K.
,
Fischer
R. L.
,
Goldberg
R. B.
,
Harada
J. J.
(
1998
)
ArabidopsisLEAFYCOTYLEDON1 is sufficient to induce embryo development in vegetative cells.
Cell
93
,
1195
1205
Luerssen
H.
,
Kirik
V.
,
Herrmann
P.
,
Misera
S.
(
1998
)
FUSCA3 encodes a protein with a conserved VP1/AB13-like B3 domain which is of functional importance for the regulation of seed maturation in Arabidopsis thaliana.
Plant J
15
,
755
764
Mayer
U.
,
Torres Ruiz
R. A.
,
Berleth
T.
,
Misera
S.
,
Jurgens
G.
(
1991
)
Mutations affecting body organization in the Arabidopsis embryo.
Nature
353
,
402
407
Meinke
D. W.
,
L.H. F.
,
Nickle
T. C.
,
Yeung
E. C.
(
1994
)
Leafy cotyledon mutants of Arabidopsis.
Plant Cell
6
,
1049
1064
Nambara
E.
,
Keith
K.
,
McCourt
P.
,
Naito
S.
(
1995
)
A regulatory role for the ABI3 gene in the establishment of embryo maturation in Arabidopsis.
Development
121
,
629
686
Nambara
E.
,
Hayama.
R.
,
Tsuchiya
Y.
,
Nishimura
,
Kawaide
H.
,
Kamiya
Y.
,
Naito
S.
(
2000
)
The role of ABI3 and FUS3 loci in Arabidopsis thaliana on phase transition from late embryo development to germination.
Dev. Biol
220
,
412
423
Opsahl-Ferstad
H.-G.
,
Le Deunff
E.
,
Dumas
C.
,
Rogowsky
P. M.
(
1997
)
ZmEsr, a novel endosperm-specific gene expressed in a restricted region around the maize embryo.
Plant J
12
,
235
246
Parcy
F.
,
Valon
C.
,
Kohara
A.
,
Misera
S.
,
Giraudat
J.
(
1997
)
The ABSCISIC ACID-INSENSITIVE3, FUSCA3, and LEAFY COTYLEDON1 loci act in concert to control multiple aspects of Arabidopsis seed development.
Plant Cell
9
,
1265
1277
Raz
V.
,
Ecker
J. R.
(
1999
)
Regulation of differential growth in the apical hook of Arabidopsis.
Development
126
,
3661
3668
Robertson
D. S.
(
1955
)
The genetics of vivipary in maize.
Genetics
40
,
745
760
Rohde
A.
,
De Rycke
R.
,
Beeckman
T.
,
Engler
G.
,
Van Montagu
M.
,
Boerjan
W.
(
2000
)
ABI3 affects plastid differentiation in dark-grown Arabidopsis seedlings.
Plant Cell
12
,
35
52
Russell
L.
,
Larner
V.
,
Kurup
S.
,
Bougourd
S.
,
Holdsworth
M.
(
2000
)
The Arabidopsis COMATOSE locus regulates germination potential.
Development
127
,
3759
3767
Shirley
B. W.
,
Kubasek
W. L.
,
Storz
G.
,
Bruggemann
E.
,
Koornneef
M.
,
Ausubel
F. M.
,
Goodman
H. M.
(
1995
)
Analysis of Arabidopsis mutants deficient in flavonoid biosynthesis.
Plant J
8
,
659
671
Siddiqi
I.
,
Ganesh
G.
,
Grossniklaus
U.
,
Subbiah
V.
(
1999
)
The dyad gene is required for progression through female meiosis in Arabidopsis.
Development
127
,
197
207
Steber
C. M.
,
Cooney
S. E.
,
McCourt
P.
(
1998
)
Isolation of the GA-response mutant sly1 as a suppressor of ABI1-1 in Arabidopsis thaliana.
Genetics
149
,
509
521
Walker
J. D.
,
Oppenheimer
D. G.
,
Concienne
J.
,
Larkin
J. C.
(
2000
)
SIAMESE, a gene controlling the endoreduplication cell cycle in Arabidopsis thaliana trichomes.
Development
127
,
3931
3940
West
M. A. L.
,
Matsudaira Yee
K.
,
Danao
J.
,
Zimmerman
J. L.
,
Fischer
R. L.
,
Goldberg
R. B.
,
Harada
J. J.
(
1994
)
Leafy cotyledon1 is an essential regulator of late embryogenesis and cotylrdon identity in Arabidopsis.
Plant Cell
6
,
1731
1745
White
C. N.
,
Rivin
C. J.
(
2000
)
Gibberellins and seed development in maize. II. Gibberellin synthesis inhibition enhances abscisic acid signaling in cultured embryos.
Plant Physiol
122
,
1089
1097
This content is only available via PDF.