ISSN 10214437, Russian Journal of Plant Physiology, 2015, Vol. 62, No. 1, pp. 109–115. © Pleiades Publishing, Ltd., 2015.
Sweet potato is one of important food and eco
nomic crops all over the world. With wide planting
areas, it can grow in barren land and have high yield.
In China, sweet potato is extensively cultivated, and
varieties are different from the South to the North.
Sweet potato possesses high nourishment value
because it is rich in protein, starch, vitamin, and many
minerals. As food, sweet potato is acclaimed as one of
the best vegetables; it can fight against cancer, improve
immunity, and also have an antiaging effect. In addi
tion, sweet potato can be used for ethanol production
to decrease our dependence on fossil fuel .
As a vital environmental factor, light has profound
effects on the growth and development of plants.
Besides providing an energy source by photosynthesis,
it also supplies informational cues to regulate the
developmental patterns of the higher plants . Dur
ing higher plant evolution, several photoreceptors
have developed, such as phytochromes, crypto
chromes, and phototropins. These photoreceptors
This text was submitted by the authors in English.
have specific absorption spectra and play various roles
in the plant life cycle.
Phytochrome, a soluble chromoprotein of about
120 kD, is a crucial photoreceptor, which can perceive
red/farred light (RLFRL) and regulate various phys
iological as well as developmental processes in the
plants . The distribution of phytochromes varies
among different species. For instance, there are five
kinds of phytochrome genes
; however, there
are only three types
[5, 6]. In addition to plant phytochromes, phy
tochromerelated proteins are also present in many
bacterial species and fungi . Different phytochrome
members were characterized by distinct and overlap
ping functions. A multigene family encodes phyto
chromes in higher plants , and phytochromes exist in
two spectrally distinct forms, the inactive RLabsorbing
form (Pr) and the active FRLabsorbing form (Pfr).
Previous results revealed that Pr and Pfr forms pos
sessing the characteristics of kinase can be phosphory
lated and regulated by light. RL can activate phyto
chrome by transforming Pr into Pfr, and Pfr is trans
formed back into Pr via FRL absorption . The
analysis of structure showed that all of the higher plant
phytochromes had the similar primary structure. Phy
Cloning, Expression, and Characterization of
J. X. Wang
, Y. S. Jiang
, Y. Yan
, X. Tao
, and Y. Z. Zhang
College of Life Science, Sichuan University, Key Laboratory of Resource Biology & Ecoenvironment, Ministry of Education,
Sichuan Key Laboratory of Molecular Biology & Biotechnology, Chengdu, Sichuan 610064,
College of Life Science & Forestry, Chongqing University of Art & Science, Chongqing, 402160, China
fax: +8602885412738; email: firstname.lastname@example.org
Received December 2, 2013
—Phytochrome A (phyA), as a photoreceptor, has a profound influence on plant growth and devel
opment and participates in many important physiological processes, such as seed germination, seeding de
etiolation, and flowering. On the basis of transcriptome database of sweet potato (
gene was cloned and sequenced. The gene has an open reading frame (ORF) of 3384 bp, encodes a pro
tein with 1127 amino acid residues and a mol wt of 125.03 kD. More interestingly, it was found that there were
three highly homologous
cDNA isoforms in sweet potato. In addition, when the genomic sequence of
gene was obtained by PCR using sweet potato genomic DNA as a template, it contained 4 exons and
3 introns with a total size of 4957 bp. The cDNA of
gene was inserted into the vector pET32a(+) and
successfully expressed in
BL21(DE3). The results of quantitative realtime PCR indicated
that the expression level of
gene was higher in stem, followed by leaf, and the lowest in tuberous root.
Besides, the expression of
mRNA in the mature leaf showed an obvious circadian rhythm in a day:
mRNA accumulation gradually increased in darkness and decreased in the daylight.
Keywords: Ipomoea batatas
, gene cloning, gene expression, realtime PCR
: FRL—farred light; HIR—high irradiance
response; phyA—phytochrome A; RL—red light; VLFR—very
low fluence response.