title: An inducible NADPH-cytochrome P450 reductase from Picrorhiza kurrooa - an imperative redox partner of cytochrome P450 enzymes.
abstract: Picrorhiza kurrooa synthesizes a large array of pharmacologically important monoterpenoid iridoid glycosides called picrosides. Although chemical profile and pharmacological activities of P. kurrooa have been extensively studied, limited attempts have been made to decipher the biosynthetic route and to identify the key regulatory genes involved in picroside biosynthesis. In the present study, NADPH-cytochrome P450 reductase, a key enzyme involved in electron transfer to cytochrome P450s was identified from P. kurrooa. The full length cDNA (2679 bp) contained an open reading frame of 2133 bp, corresponding to 710 amino acids. PkCPR was heterologously expressed in Escherichia coli and the kinetic parameters of the recombinant enzyme were determined. Specific activity, V max and K m of PkCPR were found to be 5.8 ± 0.05 μmol min(-1) mg(-1), 8.1 ± 0.12 μmol min(-1) mg(-1) and 7.8 μM, respectively. PkCPR was found to be spatially regulated at transcript level, being maximally expressed in leaf tissues. Altitude was found to have a positive effect on the picroside concentration and the picroside content positively correlated with the PkCPR transcript levels in samples collected at varied altitudes. Further, transcript profiling under methyl jasmonate, salicylic acid, 2,4-dicholorophenoxy acetic acid and UV-B elicitations displayed differential transcriptional regulation of PkCPR that fully corroborated with the identified cis-elements within the PkCPR promoter. Expression of PkCPR was inducible by UV-B and phytohormone elicitation, indicating that the PkCPR is possibly related to defence reactions, including biosynthesis of secondary metabolites. Present study is so far the only report of identification and functional characterization of CPR ortholog from P. kurrooa.
authors: Plant Biotechnology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi-180001, India.
authors: Wajid Waheed
authors: WW
authors: Bhat
authors: Satiander
authors: S
authors: Rana
authors: Niha
authors: N
authors: Dhar
authors: Sumeer
authors: S
authors: Razdan
authors: Shahzad A
authors: SA
authors: Pandith
authors: Ram
authors: R
authors: Vishwakarma
authors: Surrinder K
authors: SK
authors: Lattoo
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D000085:Acetates / Q000494:pharmacology; D000531:Altitude; D003517:Cyclopentanes / Q000494:pharmacology; D004789:Enzyme Activation; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D057888:Iridoid Glucosides / Q000378:metabolism; D007700:Kinetics; D053858:Metabolic Networks and Pathways; D009251:NADPH-Ferrihemoprotein Reductase / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D054883:Oxylipins / Q000494:pharmacology; D032261:Picrorhiza / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D057888:Iridoid Glucosides; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011994:Recombinant Proteins; D015084:2,4-Dichlorophenoxyacetic Acid; C072239:methyl jasmonate; D009251:NADPH-Ferrihemoprotein Reductase; D020156:Salicylic Acid