Molecular Characterization of the Gene for Dihydroflavonol 4-Reductase of Japonica Rice Varieties.

Nakai, K.; Inagaki, Yoshishige; Nagata, Hisanori; Miykzaki, Chikara; Iida, Shigeru

doi:10.5511/plantbiotechnology.15.221

Cited by 17 publications

(17 citation statements)

References 11 publications

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“…The DFR gene consists of three exons and two introns in rice (Chen et al. , 1998; Nakai et al. , 1998).…”

Section: Resultsmentioning

confidence: 99%

“…, 1998). In the DFR genes of Japonica varieties, either the GAG sequence (codon position: third amino acid from Met) at exon 1 in the Koshihikari variety or the TCG sequence (codon position: 55th amino acid from Met) at exon 2 in the Toride variety, is replaced by the stop codon TAG (Nakai et al. , 1998).…”

Section: Resultsmentioning

confidence: 99%

“…Because these cultivars have the stop codon at exon 1 and 2 in the DFR gene, the gene may not be functional. Transcription of the DFR gene from several rice varieties has been confirmed by Nakai et al. (1998); however, translation into the DFR protein has not been examined.…”

Section: Resultsmentioning

confidence: 99%

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The Rc and Rd genes are involved in proanthocyanidin synthesis in rice pericarp

et al. 2006

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Summary Different colors, such as purple, brown, red and white, occur in the pericarp of rice. Here, two genes affecting proanthocyanidin synthesis in red‐ and brown‐colored rice were elucidated. Genetic segregation analysis suggested that the Rd and A loci are identical, and both encode dihydroflavonol‐4‐reductase (DFR). The introduction of the DFR gene into an Rcrd mutant resulted in red‐colored rice, which was brown in the original mutant, demonstrating that the Rd locus encodes the DFR protein. Accumulation of proanthocyanidins was observed in the transformants by the introduction of the Rd gene into the rice Rcrd line. Protein blot analysis showed that the DFR gene was translated in seeds with alternative translation initiation. A search for the Rc gene, which encodes a transacting regulatory factor, was conducted using available DNA markers and the Rice Genome Automated Annotation System program. Three candidate genes were identified and cloned from a rice RcRd line and subsequently introduced into a rice rcrd line. Brown‐colored seeds were obtained from transgenic plants by the introduction of a gene containing the basic helix–loop–helix (bHLH) motif, demonstrating that the Rc gene encodes a bHLH protein. Comparison of the Rc locus among rice accessions showed that a 14‐bp deletion occurred only in the rc locus.

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“…The DFR gene consists of three exons and two introns in rice (Chen et al. , 1998; Nakai et al. , 1998).…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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The Rc and Rd genes are involved in proanthocyanidin synthesis in rice pericarp

et al. 2006

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“…In many plant species, the expression of a single DFR gene accounts for the observed complex patterns of metabolite accumulation (Gerats et al, 1990;Kristiansen and Rohde, 1991;Winkel-Shirley et al, 1992;Bongue-Bartelsman et al, 1994;Sparvoli et al, 1994;Holton and Cornish, 1995;Chen et al, 1998;Elomaa et al, 1998;Nakai et al, 1998;Hoshino et al, 2001). For the two M. truncatula DFR genes, the patterns of transcript accumulation were remarkably similar in most of the tissues examined, despite the observed differences in in vitro kinetic parameters.…”

Section: Two Dihyroflavonol-4-reductase Cdnas From Medicago Truncatulamentioning

confidence: 99%

Molecular and Biochemical Analysis of Two cDNA Clones Encoding Dihydroflavonol-4-Reductase fromMedicago truncatula

et al. 2004

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Dihydroflavonol-4-reductase (DFR; EC1.1.1.219) catalyzes a key step late in the biosynthesis of anthocyanins, condensed tannins (proanthocyanidins), and other flavonoids important to plant survival and human nutrition. Two DFR cDNA clones (MtDFR1 and MtDFR2) were isolated from the model legume Medicago truncatula cv Jemalong. Both clones were functionally expressed in Escherichia coli, confirming that both encode active DFR proteins that readily reduce taxifolin (dihydroquercetin) to leucocyanidin. M. truncatula leaf anthocyanins were shown to be cyanidin-glucoside derivatives, and the seed coat proanthocyanidins are known catechin and epicatechin derivatives, all biosynthesized from leucocyanidin. Despite high amino acid similarity (79% identical), the recombinant DFR proteins exhibited differing pH and temperature profiles and differing relative substrate preferences. Although no pelargonidin derivatives were identified in M. truncatula, MtDFR1 readily reduced dihydrokaempferol, consistent with the presence of an asparagine residue at a location known to determine substrate specificity in other DFRs, whereas MtDFR2 contained an aspartate residue at the same site and was only marginally active on dihydrokaempferol. Both recombinant DFR proteins very efficiently reduced 5-deoxydihydroflavonol substrates fustin and dihydrorobinetin, substances not previously reported as constituents of M. truncatula. Transcript accumulation for both genes was highest in young seeds and flowers, consistent with accumulation of condensed tannins and leucoanthocyanidins in these tissues. MtDFR1 transcript levels in developing leaves closely paralleled leaf anthocyanin accumulation. Overexpression of MtDFR1 in transgenic tobacco (Nicotiana tabacum) resulted in visible increases in anthocyanin accumulation in flowers, whereas MtDFR2 did not. The data reveal unexpected properties and differences in two DFR proteins from a single species.Flavonoids represent a large group of plant secondary metabolites with diverse biological activities, and the biochemical and genetic investigations of flavonoid biosynthesis have been well documented (Hahlbrock and Grisebach, 1975;Harborne, 1988;Stafford, 1990;Holton and Cornish, 1995;Dixon and Steele, 1999;Winkel-Shirley, 2001). Flavonoids are divided into several structural classes, including anthocyanins, which provide flower and leaf colors, catechins, and condensed tannins (CTs; proanthocyanidins), which contribute to resistance to microbes, and other derivatives with diverse roles in plant development and interactions with the environment (Harborne, 1988;Dixon and Paiva, 1995;Paiva, 2000). Several flavonoids are active ingredients in herbal medicines and appear to confer health benefits to humans when consumed regularly. Particular attention has been placed on the anthocyanins, catechins, and proanthocyanidins because of their antioxidant activities and their interactions with proteins (Tanner et al., 1994;Scalbert and Williamson, 2000;Ross and Kasum, 2002;Hou, 2003).The common precursors in the ...

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“…In Arabidopsis siliques, DFR expression requires the TT8 gene which encodes the R transcription factor containing a helix-loop-helix domain (Nesi et al 2000). Rice and barley have one or two putative P-binding sites in the 5' upstream regions of DFR (Kristiansen et al 1991;Nakai et al 1998).…”

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confidence: 99%

Expression Analysis of Dihydroflavonol 4-Reductase Genes Involved in Anthocyanin Biosynthesis in Purple Grains of Wheat

Liu¹,

Wang²,

Dong³

et al. 2005

J Integrative Plant Biology

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Abstract:The grain color of wheat (Triticum aestivum L.) is an important characteristic in crop production. Dihydroflavonol 4-reductase genes (DFR) encode the key enzyme dihydroflavonol 4-reductase, which is involved in the pigmentation of plant tissues. To investigate the molecular mechanism of anthocyanin deposition in grains of wheat, we determined the expression of the wheat DFR gene in purple grains of cultivar Heimai 76. The results showed that DFR transcripts were localized in the seed coat of purple grains rather than in the pericarp, whereas anthocyanins were accumulated in both tissues of purple grains, suggesting that anthocyanin deposition was mainly regulated at the transcriptional level. Overexpression of the TaDFR-A gene in Arabidopsis showed that TaDFR-A was responsible for the pigmentation of Arabidopsis plant tissues, indicating TaDFR-A gene has the same role in Arabidopsis.

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Molecular Characterization of the Gene for Dihydroflavonol 4-Reductase of Japonica Rice Varieties.

Cited by 17 publications

References 11 publications

The Rc and Rd genes are involved in proanthocyanidin synthesis in rice pericarp

The Rc and Rd genes are involved in proanthocyanidin synthesis in rice pericarp

Molecular and Biochemical Analysis of Two cDNA Clones Encoding Dihydroflavonol-4-Reductase fromMedicago truncatula

Expression Analysis of Dihydroflavonol 4-Reductase Genes Involved in Anthocyanin Biosynthesis in Purple Grains of Wheat

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