Basic HTML Version
Molecular Plant Breeding 2011, Vol.2, No.9, 60
-
67
http://mpb.sophiapublisher.com
60
Research Letter Open Access
Evolution of the Genes Encoding Starch Synthase in Sorghum and Come Wheat
Xiaoxue Pan
1,3
, Hongbo Yan
2
, Meiru Li
1
, Guojiang Wu
1
, Huawu Jiang
1
1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou
510650;
2 Bioscience and Bioengineering School, Hebei University of Economics and Business, Shijiazhuang, 050061;
3 Graduate University of the Chinese Academy of Sciences, Beijing, 100049
Corresponding author email:
hwjiang@scbg.ac.cn;
Author
Molecular Plant Breeding, 2011, Vol.2 No.9 doi: 10.5376/mpb.2011.02.0009
Received: 16, Mar., 2011
Accepted: 03, May, 2011
Published: 21, Jun., 2011
This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Pan et al., 2011, Evolution of the Genes Encoding Starch Synthase in Sorghum and Come Wheat, Molecular Plant Breeding Vol.2 No.9 (doi:
10.5376/mpb.2011.02.0009)
Abstract
Starch synthases (SSs) play important roles in plant starch synthesis. Five enzymetic isoforms of starch synthases have
been found in plant, some of isoforms have further diverged possibly via whole genome duplication events, which might result in two
or three subclasses of the sequences in rice and maize. In this study, we found the retention of GBSS, SS
Ⅱ
, and SS
Ⅲ
duplicator
except for the SS
Ⅳ
duplicator in genomes of sorghum and come wheat. The SS
Ⅳ
a gene might have been lost in maize and sorghum
genomes based on the synteny relationship among rice maize and sorghum. Expression analyses indicated that the SS duplicators
were also diverged from the duplicators of
SbGBSS
Ⅰ
,
SbSS
Ⅲ
a
in expression pattern, and
SbSS
Ⅱ
a
were expressed mainly in
endosperm in sorghum, whereas
SbGBSS
Ⅱ
,
SbSS
Ⅱ
b
, and
SbSS
Ⅲ
b
of sorghum,
TaSS
Ⅱ
b
and
TaSS
Ⅲ
b
of common wheat, were
expressed mainly in leaves. Our observations together with previous studies, indicate that the SS
Ⅳ
duplicator should be not
remained in all Gramineae species, while the expression of duplicated
SS
genes diverged similarly in the studied species.
Keywords
Starch synthesis; gene duplication; gene divergence; sorghum; come wheat
Background
Whole genome duplication (WGD) or polyploidy
event is a prominent process in Gramineae plants and
has been significant in the evolution and separation
history (Wendel, 2000). Interdisciplinary approaches
combining phylogenetic and structural genomic data
suggest that the Gramineae genes have undergo a
WGD about 70 million years ago (Mya) before the
divergence of the Gramineae (Paterson et al., 2004).
In addition, it also found that the maize genome is the
product of a genomic allotetraploid event approximately
12 Mya ago (Gaut and Doebley, 1997). Subsequently,
the maize genome ‘diploidized’ by deleting most of
the duplicated centromere regions and deleting or
tolerating the degeneration of one number of most of
its paired genes (Song and Messing, 2003; Brunner et
al., 2005).
Starch is the main storage carbohydrate in plants and
also by far the major carbon source in Gramineae
seeds and is used as a primary store of energy for
metabolism and biosynthesis. Starch is composed of
glucose (Glc) polymer that occurs in two main forms:
amylose and amylopectin. Both type starches are
synthesized inside plastids in higher plants, and are
achieved through the coordinated interactions of
several of starch biosynthetic enzymes, including
ADP glucose pyrophosphorylase (AGPase), starch
synthase (SS), starch branching enzyme (BE), and
starch debranching enzyme (DBE) (Ball and Morell,
2003). The duplicate sets of some genes which
involved in the core pathway of starch biosynthesis
were retained in rice, maize, and wheat following the
ancient WGD event in Gramineae (Harn et al., 1998;
Vrinten and Nakamura, 2000; Hirose and Terao, 2004;
Dian et al., 2005).
The starch synthase (SS, EC 2.4.1.21) catalyzes the
synthesis of the glucan polymers by transfering the
glucosyl moiety from ADP-Glc to the nonreducing
end of a preexisting α
-
1,4 linked glucan primer.
Multiple isoforms of SSs are found in plants (Smith et