ISSN 10214437, Russian Journal of Plant Physiology, 2010, Vol. 57, No. 1, pp. 74–78. © Pleiades Publishing, Ltd., 2010.
Published in Russian in Fiziologiya Rastenii, 2010, Vol. 57, No. 1, pp. 81–85.
In wheat (
L.), starch is a major
component of grain yield, accounting for 65 to 75% of
the final dry weight of the grain , and an important
factor affecting the processing quality of wheat. Many
studies have indicated that both the appearance and
nutritional quality of the food are obviously affected by
starch content of the flour, starch components and
properties. Both physical and chemical properties of
starch are directly influenced by the ratio of amylose to
amylopectin . The higher amylose content in the
flour is linked with the smaller volume and less elastic
ity of steam bread and the worse cooking quality of
noodle, while the medium or lower amylose content in
the flour resulted in the improvement of the elasticity
and nutritional quality of steam bread or noodle .
Hence, a better understanding of the mechanism for
starch accumulation and its component variation
would be helpful both to improve process quality and
to promote grain yield of wheat.
Many researchers probed into the mechanism of
starch synthesis by investigating activities of the
enzymes involved in sucrose metabolism and starch
This text was submitted by the authors in English.
synthesis, because the process of sucrose transforming
into starch is controlled by a series of enzymes after pho
tosynthate transport to the grain. It has been reported
that the enzymes involved in starch synthesis, including
sucrose synthase (SuSy; EC 126.96.36.199), ADPglucose
pyrophosphorylase (AGPase; EC 188.8.131.52), starch syn
thases (SSS and GBSS; EC 184.108.40.206), and starch branch
ing enzyme (SBE; EC 220.127.116.11), play key roles in starch
synthesis and accumulation in wheat grains [4–7].
However, little is known about the differences in activ
ities of the enzymes involved in sucrose metabolism,
starch synthesis, and starch accumulation characteris
tics between wheat cultivars differing in starch con
tent. The objective of this study was to investigate any
differences that may be found in starch accumulation
of wheat cultivars differing in starch content. The
activities of SuSy, AGPase, SSS, GBSS, and SBE in
relation to starch accumulation in two wheat cultivars
contrasting in starch content were investigated.
MATERIALS AND METHODS
Plant materials and experiment description.
winter wheat (
L.) cultivars, BY535
(starch content of 69.5%) and JM20 (starch content of
63.5%), were used in the experiment. The experiment
was carried out at Tai’an (36
E) and Dezhou
E), P.R. China, respectively, in the
2005–2006 growing season. In Tai’an, the 0–20cm
soil layer contained 71.5 mg/kg available nitrogen,
12.5 mg/kg available phosphate, and 80.5 mg/kg
Activities of Enzymes Involved in Starch Synthesis
in Wheat Grains Differing in Starch Content
Biology Department, Dezhou University, Dezhou, Shandong, 253023 P.R. China;
Received August 21, 2008
—This work was carried out to characterize starch accumulation and activities of key enzymes dur
ing grain filling in two wheat cultivars differing in starch content. The results showed that the starch accumu
lation rate (SAR) and activities of sucrose synthase, ADPglucose pyrophosphorylase, soluble starch syn
thase, granulebound starch synthase, and starch branching enzyme in the cultivar with a high starch content
were significantly higher than those in the cultivar with a low starch content. The simulation with Richards'
equation showed that it was average starch accumulation rate but not active starch accumulation duration that
determined starch accumulation. As compared with the cultivar with a low starch content, plants of the cul
tivar with a high starch content maintained the higher SAR and greater activities of related enzymes during
mid and late grain filling stages. Consequently, the cultivar with a high starch content had advantages over that
with a low starch content in terms of the amount of starch accumulation at mid and late grain filling stages.
Key words: Triticum aestivum starch synthesis enzyme activities
: AGPase—ADPglucose pyrophosphorylase;
days post anthesis; GBSS—granulebound starch syn
polyvinylpyrrolidone30; SAR—starch accumula
tion rate; SBE—starch branching enzyme; SSS—soluble starch
synthase; SuSy—sucrose synthase.