PJB-2011-273
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.
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