First published online June 22, 2007; 10.1104/pp.107.102533
Plant Physiology 144:2009-2023 (2007)
© 2007 American Society of Plant Biologists
OPEN ACCESS ARTICLE
SYSTEMS BIOLOGY, MOLECULAR BIOLOGY, AND GENE REGULATION
Characterization of SSIIIa-Deficient Mutants of Rice: The Function of SSIIIa and Pleiotropic Effects by SSIIIa Deficiency in the Rice Endosperm[C],[OA]
Naoko Fujita*,
Mayumi Yoshida,
Tomonori Kondo,
Kaori Saito,
Yoshinori Utsumi,
Takashi Tokunaga,
Aiko Nishi,
Hikaru Satoh,
Jin-Hee Park,
Jay-Lin Jane,
Akio Miyao,
Hirohiko Hirochika and
Yasunori Nakamura
Department of Biological Production, Akita Prefectural University, Akita City, Akita 010–0195, Japan (N.F., M.Y., T.K., K.S., Y.U., Y.N.); Core Research for Evolutional Science and Technology, Japan Science and Technology, Kawaguchi, Saitama 332–0012, Japan (N.F., M.Y., Y.N.); Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, Hakozaki, Fukuoka 812–8581, Japan (T.T., A.N., H.S.); Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa 50011–1120 (J.-H.P., J.-L.J.); and National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305–8602, Japan (A.M., H.H.)
Starch synthase IIIa (SSIIIa)-deficient rice (Oryza sativa) mutants were generated using retrotransposon insertion and chemical mutagenesis. The lowest migrating SS activity bands on glycogen-containing native polyacrylamide gel, which were identified to be those for SSIIIa, were completely absent in these mutants, indicating that they are SSIIIa null mutants. The amylopectin B2 to B4 chains with degree of polymerization (DP) 30 and the Mr of amylopectin in the mutant were reduced to about 60% and 70% of the wild-type values, respectively, suggesting that SSIIIa plays an important part in the elongation of amylopectin B2 to B4 chains. Chains with DP 6 to 9 and DP 16 to 19 decreased while chains with DP 10 to 15 and DP 20 to 25 increased in the mutants amylopectin. These changes in the SSIIIa mutants are almost opposite images of those of SSI-deficient rice mutant and were caused by 1.3- to 1.7-fold increase of the amount of SSI in the mutants endosperm. Furthermore, the amylose content and the extralong chains (DP 500) of amylopectin were increased by 1.3- and 12-fold, respectively. These changes in the composition in the mutants starch were caused by 1.4- to 1.7-fold increase in amounts of granules-bound starch synthase (GBSSI). The starch granules of the mutants were smaller with round shape, and were less crystalline. Thus, deficiency in SSIIIa, the second major SS isozyme in developing rice endosperm affected the structure of amylopectin, amylase content, and physicochemical properties of starch granules in two ways: directly by the SSIIIa deficiency itself and indirectly by the enhancement of both SSI and GBSSI gene transcripts.
The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Naoko Fujita (naokof{at}akita-pu.ac.jp).
[C] Some figures in this article are displayed in color online but in black and white in the print edition.
[OA] Open Access articles can be viewed online without a subscription.
www.plantphysiol.org/cgi/doi/10.1104/pp.107.102533
* Corresponding author; e-mail naokof{at}akita-pu.ac.jp; fax 81–18–872–1681.
Received May 17, 2007;
accepted June 15, 2007;
published June 22, 2007.
This article has been cited by other articles:

|
 |

|
 |
 
H. Satoh, K. Shibahara, T. Tokunaga, A. Nishi, M. Tasaki, S.-K. Hwang, T. W. Okita, N. Kaneko, N. Fujita, M. Yoshida, et al.
Mutation of the Plastidial {alpha}-Glucan Phosphorylase Gene in Rice Affects the Synthesis and Structure of Starch in the Endosperm
PLANT CELL,
July 1, 2008;
20(7):
1833 - 1849.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
I. Hanashiro, K. Itoh, Y. Kuratomi, M. Yamazaki, T. Igarashi, J.-i. Matsugasako, and Y. Takeda
Granule-Bound Starch Synthase I is Responsible for Biosynthesis of Extra-Long Unit Chains of Amylopectin in Rice
Plant Cell Physiol.,
June 1, 2008;
49(6):
925 - 933.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
T. A. Hennen-Bierwagen, F. Liu, R. S. Marsh, S. Kim, Q. Gan, I. J. Tetlow, M. J. Emes, M. G. James, and A. M. Myers
Starch Biosynthetic Enzymes from Developing Maize Endosperm Associate in Multisubunit Complexes
Plant Physiology,
April 1, 2008;
146(4):
1892 - 1908.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|
|