Dataset Information

A bHLH transcription factor, DvIVS, is involved in regulation of anthocyanin synthesis in dahlia (Dahlia variabilis).

ABSTRACT: Dahlias (Dahlia variabilis) exhibit a wide range of flower colours because of accumulation of anthocyanin and other flavonoids in their ray florets. Two lateral mutants were used that spontaneously occurred in 'Michael J' (MJW) which has yellow ray florets with orange variegation. MJOr, a bud mutant producing completely orange ray florets, accumulates anthocyanins, flavones, and butein, and MJY, another mutant producing completely yellow ray florets, accumulates flavones and butein. Reverse transcription-PCR analysis showed that expression of chalcone synthase 1 (DvCHS1), flavanone 3-hydroxylase (DvF3H), dihydroflavonol 4-reductase (DvDFR), anthocyanidin synthase (DvANS), and DvIVS encoding a basic helix-loop-helix transcription factor were suppressed, whereas that of chalcone isomerase (DvCHI) and DvCHS2, another CHS with 69% nucleotide identity with DvCHS1, was not suppressed in the yellow ray florets of MJY. A 5.4 kb CACTA superfamily transposable element, transposable element of Dahlia variabilis 1 (Tdv1), was found in the fourth intron of the DvIVS gene of MJW and MJY, and footprints of Tdv1 were detected in the variegated flowers of MJW. It is shown that only one type of DvIVS gene was expressed in MJOr, whereas these plants are likely to have three types of the DvIVS gene. On the basis of these results, the mechanism regulating the formation of orange and yellow ray florets in dahlia is discussed.

SUBMITTER: Ohno S

PROVIDER: S-EPMC3193017 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A bHLH transcription factor, DvIVS, is involved in regulation of anthocyanin synthesis in dahlia (Dahlia variabilis).

Ohno Sho S Hosokawa Munetaka M Hoshino Atsushi A Kitamura Yoshikuni Y Morita Yasumasa Y Park Kyeung-Ii KI Nakashima Akiko A Deguchi Ayumi A Tatsuzawa Fumi F Doi Motoaki M Iida Shigeru S Yazawa Susumu S

Journal of experimental botany 20110716 14

Dahlias (Dahlia variabilis) exhibit a wide range of flower colours because of accumulation of anthocyanin and other flavonoids in their ray florets. Two lateral mutants were used that spontaneously occurred in 'Michael J' (MJW) which has yellow ray florets with orange variegation. MJOr, a bud mutant producing completely orange ray florets, accumulates anthocyanins, flavones, and butein, and MJY, another mutant producing completely yellow ray florets, accumulates flavones and butein. Reverse tran ...[more]

PMID: 21765172

Similar Datasets

Project description:BACKGROUND: Red coloration of fruit is an important trait in apple, and it is mainly attributed to the accumulation of anthocyanins, a class of plant flavonoid metabolites. Anthocyanin biosynthesis is genetically determined by structural and regulatory genes. Plant tissue pigmentation patterns are mainly controlled by expression profiles of regulatory genes. Among these regulatory genes are MYB transcription factors (TFs), wherein the class of two-repeats (R2R3) is deemed the largest, and these are associated with the anthocyanin biosynthesis pathway. Although three MdMYB genes, almost identical in nucleotide sequences, have been identified in apple, it is likely that there are other R2R3 MYB TFs that are present in the apple genome that are also involved in the regulation of coloration of red color pigmentation of the skin of apple fruits. RESULTS: In this study, a novel R2R3 MYB gene has been isolated and characterized in apple. This MYB gene is closely related to the Arabidopsis thaliana AtMYB3, and has been designated as MdMYB3. This TF belongs to the subgroup 4 R2R3 family of plant MYB transcription factors. This apple MdMYB3 gene is mapped onto linkage group 15 of the integrated apple genetic map. Transcripts of MdMYB3 are detected in all analyzed tissues including leaves, flowers, and fruits. However, transcripts of MdMYB3 are higher in excocarp of red-skinned apple cultivars than that in yellowish-green skinned apple cultivars. When this gene is ectopically expressed in Nicotiana tabacum cv. Petite Havana SR1, flowers of transgenic tobacco lines carrying MdMYB3 have exhibited increased pigmentation and accumulate higher levels of anthocyanins and flavonols than wild-type flowers. Overexpression of MdMYB3 has resulted in transcriptional activation of several flavonoid pathway genes, including CHS, CHI, UFGT, and FLS. Moreover, peduncles of flowers and styles of pistils of transgenic plants overexpressing MdMYB3 are longer than those of wild-type plants, thus suggesting that this TF is involved in regulation of flower development. CONCLUSIONS: This study has identified a novel MYB transcription factor in the apple genome. This TF, designated as MdMYB3, is involved in transcriptional activation of several flavonoid pathway genes. Moreover, this TF not only regulates the accumulation of anthocyanin in the skin of apple fruits, but it is also involved in the regulation of flower development, particularly that of pistil development.

Project description:BackgroundMore than 20,000 cultivars of garden dahlia (Dahlia variabilis hort.) are available showing flower colour from white, yellow and orange to every imaginable hue of red and purple tones. Thereof, only a handful of cultivars are so-called black dahlias showing distinct black-red tints. Flower colour in dahlia is a result of the accumulation of red anthocyanins, yellow anthochlors (6'-deoxychalcones and 4-deoxyaurones) and colourless flavones and flavonols, which act as copigments. White and yellow coloration occurs only if the pathway leading to anthocyanins is incomplete. Not in all cultivars the same step of the anthocyanin pathway is affected, but the lack of dihydroflavonol 4-reductase activity is frequently observed and this seems to be based on the suppression of the transcription factor DvIVS. The hitherto unknown molecular background for black colour in dahlia is here presented.ResultsBlack cultivars accumulate high amounts of anthocyanins, but show drastically reduced flavone contents. High activities were observed for all enzymes from the anthocyanin pathway whereas FNS II activity could not be detected or only to a low extent in 13 of 14 cultivars. cDNA clones and genomic clones of FNS II were isolated. Independently from the colour type, heterologous expression of the cDNA clones resulted in functionally active enzymes. FNS II possesses one intron of varying length. Quantitative Real-time PCR showed that FNS II expression in black cultivars is low compared to other cultivars. No differences between black and red cultivars were observed in the expression of transcription factors IVS and possible regulatory genes WDR1, WDR2, MYB1, MYB2, 3RMYB and DEL or the structural genes of the flavonoid pathway. Despite the suppression of FHT expression, flavanone 3-hydroxylase (FHT, synonym F3H) enzyme activity was clearly present in the yellow and white cultivars.ConclusionsAn increased accumulation of anthocyanins establishes the black flowering phenotypes. In the majority of black cultivars this is due to decreased flavone accumulation and thus a lack of competition for flavanones as the common precursors of flavone formation and the anthocyanin pathway. The low FNS II activity is reflected by decreased FNS II expression.

Dataset Information

A bHLH transcription factor, DvIVS, is involved in regulation of anthocyanin synthesis in dahlia (Dahlia variabilis).

Publications

A bHLH transcription factor, DvIVS, is involved in regulation of anthocyanin synthesis in dahlia (Dahlia variabilis).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets