TY - JOUR
T1 - The localization and expression of the class II starch synthases of wheat
AU - Li, Zhongyi
AU - Chu, Xiusheng
AU - Mouille, Gregory
AU - Yan, Liuling
AU - Kosar-Hashemi, Behjat
AU - Hey, Sandra
AU - Napier, Johnathan
AU - Shewry, Peter
AU - Clarke, Bryan
AU - Appels, Rudi
AU - Morell, Matthew K.
AU - Rahman, Sadequr
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1999/8
Y1 - 1999/8
N2 - The starch granules of hexaploid wheat (Triticum aestivum) contain a group of three proteins known as SGP-1 (starch granule protein-1) proteins, which have apparent molecular masses of 100, 108, and 115 kD. The nature and role of these proteins has not been defined previously. We demonstrate that these polypeptides are starch synthases that are present in both the starch granule and the soluble fraction at the early stages of wheat endosperm development, but that are exclusively granule bound at mid and late endosperm development. A partial cDNA clone encoding a fragment of the 100-kD protein was obtained by screening a wheat endosperm cDNA expression library using monoclonal antibodies. Three classes of cDNA were subsequently isolated from a wheat endosperm cDNA library by nucleic acid hybridization and were shown to encode the 100-, 108-, and 115-kD proteins. The cDNA sequences are highly homologous to class II starch synthases and have the highest homology with the maize SSIIa (starch synthase IIa) gene. mRNA for the SGP-1 proteins was detected in the leaf, pre-anthesis florets, and endosperm of wheat and is highly expressed in the leaf and in the grain during the early to mid stages of development. We discuss the roles of the SGP-1 proteins in starch biosynthesis in wheat.
AB - The starch granules of hexaploid wheat (Triticum aestivum) contain a group of three proteins known as SGP-1 (starch granule protein-1) proteins, which have apparent molecular masses of 100, 108, and 115 kD. The nature and role of these proteins has not been defined previously. We demonstrate that these polypeptides are starch synthases that are present in both the starch granule and the soluble fraction at the early stages of wheat endosperm development, but that are exclusively granule bound at mid and late endosperm development. A partial cDNA clone encoding a fragment of the 100-kD protein was obtained by screening a wheat endosperm cDNA expression library using monoclonal antibodies. Three classes of cDNA were subsequently isolated from a wheat endosperm cDNA library by nucleic acid hybridization and were shown to encode the 100-, 108-, and 115-kD proteins. The cDNA sequences are highly homologous to class II starch synthases and have the highest homology with the maize SSIIa (starch synthase IIa) gene. mRNA for the SGP-1 proteins was detected in the leaf, pre-anthesis florets, and endosperm of wheat and is highly expressed in the leaf and in the grain during the early to mid stages of development. We discuss the roles of the SGP-1 proteins in starch biosynthesis in wheat.
UR - http://www.scopus.com/inward/record.url?scp=13044272910&partnerID=8YFLogxK
U2 - 10.1104/pp.120.4.1147
DO - 10.1104/pp.120.4.1147
M3 - Article
C2 - 10444098
AN - SCOPUS:13044272910
SN - 0032-0889
VL - 120
SP - 1147
EP - 1155
JO - Plant Physiology
JF - Plant Physiology
IS - 4
ER -