First published online April 9, 2002; 10.1104/pp.010785
Plant Physiol, April 2002, Vol. 128, pp. 1264-1270
The -Amylase Induction in Endosperm during Rice Seed
Germination Is Caused by Gibberellin Synthesized in
Epithelium1
Miyuki
Kaneko,
Hironori
Itoh,
Miyako
Ueguchi-Tanaka,
Motoyuki
Ashikari, and
Makoto
Matsuoka*
BioScience Center, Nagoya University, Chikusa, Nagoya 464-8601,
Japan
We recently isolated two genes (OsGA3ox1 and
OsGA3ox2) from rice (Oryza sativa)
encoding 3 -hydroxylase, which catalyzes the final step of active
gibberellin (GA) biosynthesis (H. Itoh, M. Ueguchi-Tanaka, N. Sentoku,
H. Kitano, M. Matsuoka, M. Kobayashi [2001] Proc Natl Acad Sci USA
98: 8909-8914). Using these cloned cDNAs, we analyzed the temporal and
spatial expression patterns of the 3 -hydroxylase genes and also an
-amylase gene (RAmy1A) during rice seed germination
to investigate the relationship between GA biosynthesis and -amylase
expression. Northern-blot analyses revealed that RAmy1A
expression in the embryo occurs before the induction of
3 -hydroxylase expression, whereas in the endosperm, a high level of
RAmy1A expression occurs 1 to 2 d after the peak of
OsGA3ox2 expression and only in the absence of
uniconazol. Based on the analysis of an OsGA3ox2 null
mutant (d18-Akibare dwarf), we determined that
3 -hydroxylase produced by OsGA3ox2 is important for
the induction of RAmy1A expression and that the OsGA3ox1
product is not essential for -amylase induction. The expression of
OsGA3ox2 was localized to the shoot region and
epithelium of the embryo, strongly suggesting that active GA
biosynthesis occurs in these two regions. The synthesis of active GA in
the epithelium is important for -amylase expression in the
endosperm, because an embryonic mutant defective in shoot formation,
but which developed epithelium cells, induced -amylase expression in
the endosperm, whereas a mutant defective in epithelium development did not.
1
This work was supported in part by a
grant-in-aid from the Program for Promotion of Basic Research
Activities for Innovative Biosciences and by the Special Coordination
Fund of the Science and Technology Agency (to M.M.).
*
Corresponding author; e-mail makoto{at}nuagr1.agr.nagoya-u.ac.jp.; fax
81-52-789-5226.
© 2002 American Society of Plant Physiologists
This article has been cited by other articles:

|
 |

|
 |
 
A. M. Ismail, E. S. Ella, G. V. Vergara, and D. J. Mackill
Mechanisms associated with tolerance to flooding during germination and early seedling growth in rice (Oryza sativa)
Ann. Bot.,
January 1, 2009;
103(2):
197 - 209.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
N. E. J. Appleford, M. D. Wilkinson, Q. Ma, D. J. Evans, M. C. Stone, S. P. Pearce, S. J. Powers, S. G. Thomas, H. D. Jones, A. L. Phillips, et al.
Decreased shoot stature and grain {alpha}-amylase activity following ectopic expression of a gibberellin 2-oxidase gene in transgenic wheat.
J. Exp. Bot.,
October 4, 2007;
(2007)
erm166v1.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. Nakamura, S. Fujioka, H. Sunohara, N. Kamiya, Z. Hong, Y. Inukai, K. Miura, S. Takatsuto, S. Yoshida, M. Ueguchi-Tanaka, et al.
The Role of OsBRI1 and Its Homologous Genes, OsBRL1 and OsBRL3, in Rice
Plant Physiology,
February 1, 2006;
140(2):
580 - 590.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Y.-C. Kim, M. Nakajima, A. Nakayama, and I. Yamaguchi
Contribution of Gibberellins to the Formation of Arabidopsis Seed Coat Through Starch Degradation
Plant Cell Physiol.,
August 1, 2005;
46(8):
1317 - 1325.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. Washio
Functional Dissections between GAMYB and Dof Transcription Factors Suggest a Role for Protein-Protein Associations in the Gibberellin-Mediated Expression of the RAmy1A Gene in the Rice Aleurone
Plant Physiology,
October 1, 2003;
133(2):
850 - 863.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. Ogawa, A. Hanada, Y. Yamauchi, A. Kuwahara, Y. Kamiya, and S. Yamaguchi
Gibberellin Biosynthesis and Response during Arabidopsis Seed Germination
PLANT CELL,
July 1, 2003;
15(7):
1591 - 1604.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|
|