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Genomics and Applied Biology, 2011, Vol.2 No.1
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Figure 5 Evolutionary tress analysis of
PutAPx
Figure 6 Prediction of
PutAPx
transmembrane domain
Figure 7 pYES2
-
PutAPx confirmed by enzyme digestion and
PCR detection of transformant of yeast
Note: M: Marker
-λ/
Hin
d
Ⅲ
; A: 1,2: pYES2
-
PutAPx fusion
plasmid confirmed byenzyme (
BamH
Ⅰ
/
Xba
Ⅰ
); B: 1~4: PCR
detection of transformant of yeast with pYES2
-
PutAPx
ear stem > anther > sheath > stem > leaf > root >
female flower in order (Figure 9). Therefore, the
expression of
PutA Px
gene is universal in different
tissues, its expression of ear is highest, ear stem,
anther and sheath are higher, female flower, however,
is lowest.
2 Disscussion
Stress, such as drought, saline-alkali, hypothermy and
hyperthemy, will destroy the active oxygen detoxifi-
cation system, accumulated the active oxygen, damaged
the cytomembrane, prevected H
2
O
2
reducing to H
2
O
by ascorbate peroxidase (APX, EC1.11.1.11, active-
oxygen-eliminated enzymes) which were of high
specificity and affinity to ascorbic acid. The reaction
consumed H
2
O
2
and produced dehydroascorbic acid
Figure 8 Hyper-resistance of
PutAPx
overexpression cells to
H
2
O
2
stresses
Note: SD is Ura supplement media; A:
PutAPx
over expressing
cells pYES2-PutAPx and the pYES2 cellswere grown on SD
media (two repeat); B:
PutAPx
over expressing cells
pYES2-PutAPx and the pYES2 cells were grown on SD media
with 8 mmol/L H
2
O
2
(two repeats)
Figure 9
PutAPx
gene expression in different organ
Note: 1~8:
PutAPx
gene and Actin gene expression in leaf,
roots, stem, ear, ear stem, sheath, anther and flower; Actin:
Constitutive gene (control)
which could be reduced to ascorbic acid through
many different pathways (Lu et al., 1998). Northern
blot analysis showed the expression of APX gene of
suaeda salsa increased under salt stress (400 mmol/L
NaCl) and the enzyme activity also increased
remarkably. It demonstrated that this gene was
induced by salt. Therefore APX might play a certain
role in protecting suaeda salsa from oxidative damage