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Legume Genomics and Genetics (online), 2010, Vol. 1, No.5, 24-29
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Research Article Open Access
Identification of
AhAQ1
Encoding a Putative Aquaporin whose Expression is Regu-
lated by Salt Stress In Peanut (
Arachis hypogaea
L.)
Lijuan Pan , Qingli Yang , Zhong Zhao , Da Luo , Xiaohe Hu
Shandong Peanut Research Institute, Qingdao 266100
corresponding author email: rice407@163.com;
Authors
Legume Genomics and Genetics 2010, Vol.1 No.5 DOI:10.5376/lgg.2010.01.0005
Received: 21 Jul., 2010
Accepted: 11 Aug., 2010
Published: 18 Oct., 2010
This article was first published in the Molecular Plant Breeding (Regular Print Version), and here was authorized to redistribute 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 as:
Pan et al., 2009, Identification of
AhAQ1
Encoding a Putative Aquaporin whose Expression is Regulated by Salt Stress In Peanut (
Arachis hypogaea
L.),
Molecular Plant Breeding, 7(5): 867-872 (DOI: 10.3969/mpb.007.000867)
Abstract
The primary role of aquaporins is to control water transport in plants, which might function in plant response against
salt stress. In this research, we obtained the full-length cDNA of an aquaporin gene
AhAQ1
by RT-PCR approach from salt-stressed
peanut leaves.
AhAQ1
encodes a protein consisting of 287 amino acids with the calculated molecular mass of 30.57 kD and the
isoelectric point of 9.04. Sequence analysis indicated that AhAQ1 contained six transmembrane domains and two NPA-boxes and
phylogenetic analysis showed that the
AhAQ1
clusters were the same with the PIP1 family. The expression pattern of
AhAQ1
in
peanut tissues under high-salt treatment was examined by semi-quantitative RT-PCR, The results showed that the accumulation of
AhAQ1
transcripts was induced by salt stress. The combination of these results illustrate that
AhAQ1
may play a role in peanut in
response to salt stress.
Keywords
Peanut; Aquaporin; Gene cloning; Expression analysis; Salt stress
Background
Soil salinity is one of the major stresses in the world
that affects plant growth and causes a significant loss
of crop productivity (Wang et al., 2003; Zhu, 2003).
The high concentration of sodium ions induceion toxi-
city and osmotic stress by limiting absorption of water
from soil. Aquaporins represent a large family with
highly conserved sequence in plants (Johanson et al.,
2001; Chaumont et al., 2001; Sakurai et al., 2005). Pre-
vious studies confirmed that aquaporins play impor-
tant roles in plant water transport by heterologous
expression in
Xenopus laevis
oocytes (Preston et al.,
1992; van Hoek and Verkman et al., 1992; Maurel et
al., 1993). They form proteinaceous pores that facili-
tate the passive diffusion of water across membranes
of living cell by increasing the osmotic hydraulic con-
ductivity of the membrane (Preston et al., 1992; Sie-
fritz et al., 2002). Based on their sequence similarities
or structural features, plant aquaporins may be divided
into four groups: plasma membrane intrinsic proteins
(PIPs), tonoplast intrinsic proteins (TIPs), nodulin26-
like intrinsic proteins (NIPs) and small basic intrinsic
proteins (SIPs) (Johanson et al., 2001; Johanson and
Gustavsson 2002; Chaumont et al., 2005; Murata et al.,
2000), Among the four categories, the plasma mem-
brane intrinsic proteins (PIPs) ,which are further classi-
fied into two subfamilies, PIP1s and PIP2s (Luu and
Maurel, 2005), according to the amino acid residues at
the N- and C-terminals and the conserved NPA box.
Since the first plant aquaporin γ-TIP was isolated
from Arabidopsis
(Maurel et al., 1993), many other
aquaporins have been identified from plants involving
Arabidopsis, maize, tobacco and rice, and so on (Jo-
hanson et al., 2001; Chaumont et al., 2001; Mahdieh et
al., 2008; Sakurai et al., 2005). Numerous studies con-
firmed that many plant aquaporin genes are involved
in the response to water stresses such as drought and
salt. For example, the amount of rice water channel
protein RWC3 increased in upland rice under drought
stress, whereas decreased in lowland rice, and over-
expression of
RWC3
in lowland rice could result in an
enhanced tolerance to drought stress (Lian et al.,
2004). Another instance is that transgenic tobacco
plants expressing sense
BnPIP1
gene showed an
increased tolerance to water stress (Yu et al., 2005).
Three genes named
NeMip1
,
NeMip2
and
NeMip3
have been isolated from tobacco, and their mRNA
were accumulated by salt and drought stress (Yamada
et al., 1997). Besides, the expression of barley
HvPIP2
;
1
was downregulated after high salt treatment, and
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