Publications of NIPGR Scientists
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Item Cloning and characterization of two new Class III peroxidase genes from Catharanthus roseus(Elsevier, 2011) Kumar, Santosh; Jaggi, Monika; Taneja, Jyoti; Sinha, Alok KrishnaWe report here the cloning and characterization of two new class III peroxidase genes, CrPrx3 and CrPrx4 from Catharanthus roseus. The full length cDNA of CrPrx3 is 1233 bp long encoding 330 amino acid residues. The CrPrx4 cDNA contains an ORF of 1055 bp, and encodes for 318 amino acids. Hypothetical 3-D structure model of CrPrx3 and CrPrx4 detected the presence of two Ca(2+) ion binding sites at proximal and distal end, and a heme group coordinate at central position. CrPrx3 and CrPrx4 are present in single copy number in C. roseus. Confocal scanning microscopy and phylogenetic analysis showed that CrPrx3 and CrPrx4 are apoplastic in nature. Phylogenetic analysis revealed that both genes have diverse expression patterns in a variety of plant tissues. Quantitative real-time PCR confirmed their maximum expression in stem tissues followed by flower tissue. The expression levels of CrPrx3 and CrPrx4 were down-regulated under salt and dehydration stress, respectively.Item Overexpression of an apoplastic peroxidase gene CrPrx in transgenic hairy root lines of Catharanthus roseus(Springer Science, 2011) Jaggi, Monika; Kumar, Santosh; Sinha, Alok KrishnaPeroxidases are a family of isoenzymes found in all higher plants and are known to be involved in a broad range of physiological processes. However, very little information is available concerning their role in Catharanthus roseus. The present study describes the impact of both overexpression and suppression of a peroxidase gene, CrPrx in C. roseus transgenic hairy root lines. Real-time PCR analysis in 35S-CrPrx and CrPrx-RNAi transgenic lines indicated differential transcript profile for peroxidases as well as for genes and regulators involved in MIA (monoterpenoid indole alkaloid) pathway of C. roseus. Comparative analysis revealed that MIA pathway genes showing elevated levels of expression in 35S-CrPrx transgenic lines showed a significant reduction in their transcript level in CrPrx-RNAi transgenic lines. Metabolite analysis detected higher levels of ajmalicine and serpentine accumulation in overexpressed lines. It was observed that all overexpressed transgenic lines produced more amount of H(2)O(2). These results indicate a role of CrPrx gene in the regulation of MIA pathway genes and regulators, thus affecting the production of specific alkaloids.
