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CLONING AND
CHARACTERIZATION OF PEROXIDASE GENE IN PHALAENOPSIS
XU CHUANJUN1,2,
SUN XUZHUO1, CHEN DONGYIN1, LAI YANYAN1
AND LI LING1*
Abstract: Plant peroxidases oxidize phenolic substrates at the expense of H2O2
perform a significant function in responses to environmental stresses
via the regulation of H2O2 in plants. In this
study, a full-length cDNA encoding a peroxidase was cloned and sequenced
from leaf explants of Phalaenopsis by RT-PCR and RACE methods.
The cDNA designated as PhPOD (GenBank accession No. FJ161978 ),
is 1251 bp and contains a 1041 bp open reading frame (ORF), which
encodes a 347 amino acid peroxidase precursor, with a 24 aa N-terminal
signal peptide targeting to ndoplasmic reticulum. The putative protein
has a calculated molecular weight of 37.22 kDa and a calculated pI of
7.55. Sequence analysis showed that the deduced amino acid sequence of
PhPOD shares high identity with the reported POD protein
sequences in database and is a typical Class III of POD family in
plants. PhPOD possesses all active residues and two Ca2+
-binging sites present in peroxidase isoenzymes C, as well as six
N-glycosylation sites. Semi-quantitative RT-PCR revealed that the
expression of PhPOD was increased just before explant browning,
and decreased with the aggravating of explants browning. These results
indicate a possible function of PhPOD and provide an alternative way for
controlling explant browning in tissue culture.
1Guangdong
Provincial Key Lab of Biotechnology for Plant Development, College of
Life Science, South China Normal
University, Guangzhou, 510631, P.R. China
2Fujian
Provincial Key Lab of Subtropic Plant Physiology and Biochemisty, Fujian Institute of
Subtropic Botany, Xiamen, 361006, P.R. China.
*E-mail address:
liling@scnu.edu.cn
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