Singh, K and Kumar, Sanjay and Yadav, S K and Ahuja, Paramvir Singh (2009) Characterization of dihydroflavonol 4-reductase cDNA in tea [Camellia sinensis (L.) O. Kuntze]. Plant Biotechnology Reports, 3 (1). pp. 95-101. ISSN 1863-5466

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Abstract

Tea leaves are major source of catechins-antioxidant flavonoids. Dihydroflavonol 4-reductase (DFR, EC 1.1.1.219) is one of the important enzymes that catalyzes the reduction of dihydroflavonols to leucoanthocyanins, a key "late" step in the biosynthesis of catechins. This manuscript reports characterization of DFR from tea (CsDFR) that comprised 1,413 bp full-length cDNA with ORF of 1,044 bp (115-1,158) and encoding a protein of 347 amino acids. Sequence comparison of CsDFR with earlier reported DFR sequences in a database indicated conservation of 69-87% among amino acid residues. In silico analysis revealed CsDFR to be a membrane-localized protein with a domain (between 16 and 218 amino acids) resembling the NAD-dependent epimerase/dehydratase family. The theoretical molecular weight and isoelectric point of the deduced amino sequence of CsDFR were 38.67 kDa and 6.22, respectively. Upon expression of CsDFR in E. coli, recombinant protein was found to be functional and showed specific activity of 42.85 nmol min(-1) mg protein(-1). Expression of CsDFR was maximum in younger rather than older leaves. Expression was down-regulated in response to drought stress and abscisic acid, unaffected by gibberellic acid treatment, but up-regulated in response to wounding, with concomitant modulation of catechins content. This is the first report of functionality of recombinant CsDFR and its expression in tea.

Item Type:	Article
Uncontrolled Keywords:	Dihydroflavonol 4-reductase; Gene expression; Tea; Catechins; In-vitro activity
Subjects:	Nutraceuticals Plant Biotechnology
Divisions:	UNSPECIFIED
Depositing User:	Dr. Aparna Maitra Pati
Date Deposited:	28 Dec 2011 09:36
Last Modified:	06 Feb 2012 07:29
URI:	http://ihbt.csircentral.net/id/eprint/316

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