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Sornkanok Vimolmangkang

Bio: Sornkanok Vimolmangkang is an academic researcher from Chulalongkorn University. The author has contributed to research in topics: Medicine & Chemistry. The author has an hindex of 17, co-authored 33 publications receiving 941 citations. Previous affiliations of Sornkanok Vimolmangkang include Chinese Academy of Sciences & University of Illinois at Urbana–Champaign.
Topics: Medicine, Chemistry, Isoflavonoid, Lotus, Genistein


Papers
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Journal ArticleDOI
TL;DR: Progress has been made in ELISA with the recent advances in recombinant DNA technology, leading to increase in the range of antibodies, probes, and even systems.
Abstract: Immunoassays are antibody-based analytical methods for quantitative/qualitative analysis. Since the principle of immunoassays is based on specific antigen–antibody reaction, the assays have been utilized worldwide for diagnosis, pharmacokinetic studies by drug monitoring, and the quality control of commercially available products. Berson and Yalow were the first to develop an immunoassay, known as radioimmunoassay (RIA), for detecting endogenous plasma insulin [1], a development for which Yalow was awarded the Nobel Prize in Physiology or Medicine in 1977. Even today, after half a century, immunoassays are widely utilized with some modifications from the originally proposed system, e.g., radioisotopes have been replaced with enzymes because of safety concerns regarding the use of radioactivity, which is referred to as enzyme immunoassay/enzyme-linked immunosorbent assay (ELISA). In addition, progress has been made in ELISA with the recent advances in recombinant DNA technology, leading to increase in the range of antibodies, probes, and even systems. This review article describes ELISA and its applications for the detection of plant secondary metabolites.

314 citations

Journal ArticleDOI
TL;DR: This study has identified a novel MYB transcription factor involved in transcriptional activation of several flavonoid pathway genes in the apple genome, designated as MdMYB3, which 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.
Abstract: 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. 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. 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.

153 citations

Journal ArticleDOI
TL;DR: Findings suggest that MdF3′H genes are coordinately expressed with other genes in the anthocyanin biosynthetic pathway in apple.
Abstract: Three genes encoding flavonoid 3′-hydroxylase (F3′H) in apple (Malus × domestica), designated MdF3′HI, MdF3′HIIa, and MdF3′HIIb, have been identified. MdF3′HIIa and MdF3′HIIb are almost identical in amino acid sequences, and they are allelic, whereas MdF3′HI has 91% nucleotide sequence identity in the coding region to both MdF3′HIIa and MdF3′HIIb. MdF3′HI and MdF3′HII genes are mapped onto linkage groups 14 and 6, respectively, of the apple genome. Throughout the development of apple fruit, transcriptional levels of MdF3′H genes along with other anthocyanin biosynthesis genes are higher in the red-skinned cv Red Delicious than that in the yellow-skinned cv Golden Delicious. Moreover, patterns of MdF3′H gene expression correspond to accumulation patterns of flavonoids in apple fruit. These findings suggest that MdF3′H genes are coordinately expressed with other genes in the anthocyanin biosynthetic pathway in apple. The functionality of these apple F3′H genes has been demonstrated via their ectopic expression in both the Arabidopsis (Arabidopsis thaliana) transparent testa7-1 (tt7) mutant and tobacco (Nicotiana tabacum). When grown under nitrogen-deficient conditions, transgenic Arabidopsis tt7 seedlings expressing apple F3′H regained red color pigmentation and significantly accumulated both 4′-hydrylated pelargonidin and 3′,4′-hydrylated cyanidin. When compared with wild-type plants, flowers of transgenic tobacco lines overexpressing apple F3′H genes exhibited enhanced red color pigmentation. This suggests that the F3′H enzyme may coordinately interact with other flavonoid enzymes in the anthocyanin biosynthesis pathway.

112 citations

Journal ArticleDOI
TL;DR: Interestingly, several transgenic lines show no detectable transcripts of the gene encoding leucoanthocyanidin reductase (LAR) in flowers, but accumulate higher levels of catechin in flowers of transgenic plants than those of wild-type plants, which suggests that the ANR gene may be capable of generating cATEchin via an alternative route, although this mechanism is yet to be further elucidated.
Abstract: Three genes encoding anthocyanidin reductase (ANR) in apple (Malus×domestica Borkh.), designated MdANR1, MdANR2a, and MdANR2b, have been cloned and characterized. MdANR1 shows 91% identity in coding DNA sequences with MdANR2a and MdANR2b, while MdANR2a and MdANR2b are allelic and share 99% nucleotide sequence identity in the coding region. MdANR1 and MdANR2 genes are located on linkage groups 10 and 5, respectively. Expression levels of both MdANR1 and MdANR2 genes are generally higher in yellow-skinned cv. Golden Delicious than in red-skinned cv. Red Delicious. Transcript accumulation of MdANR1 and MdANR2 genes in fruits gradually decreased throughout fruit development. Ectopic expression of apple MdANR genes in tobacco positively and negatively regulates the biosynthesis of proanthocyanidins (PAs) and anthocyanin, respectively, resulting in white, pale pink-coloured, and white/red variegated flowers. The accumulation of anthocyanin is significantly reduced in all tobacco transgenic flowers, while catechin and epicatechin contents in transgenic flowers are significantly higher than those in flowers of wild-type plants. The inhibition of anthocyanin synthesis in tobacco transgenic flowers overexpressing MdANR genes is probably attributed to down-regulation of CHALCONE ISOMERASE (CHI) and DIHYDROFLAVONOL-4-REDUCTASE (DFR) genes involved in the anthocyanin pathway. Interestingly, several transgenic lines show no detectable transcripts of the gene encoding leucoanthocyanidin reductase (LAR) in flowers, but accumulate higher levels of catechin in flowers of transgenic plants than those of wild-type plants. This finding suggests that the ANR gene may be capable of generating catechin via an alternative route, although this mechanism is yet to be further elucidated.

107 citations

Journal ArticleDOI
TL;DR: Activation of an ancient duplicated MYB gene PpMYB10.4 in the Gr interval on LG 6, which represents a novel branch of anthocyanin-activating MYB genes in Rosaceae, is able to activate leaf red coloration in peach.
Abstract: Leaf red coloration is an important characteristic in many plant species, including cultivars of ornamental peach (Prunus persica). Peach leaf color is controlled by a single Gr gene on linkage group 6, with a red allele dominant over the green allele. Here, we report the identification of a candidate gene of Gr in peach. The red coloration of peach leaves is due to accumulation of anthocyanin pigments, which is regulated at the transcriptional level. Based on transcriptome comparison between red- and green-colored leaves, an MYB transcription regulator PpMYB10.4 in the Gr interval was identified to regulate anthocyanin pigmentation in peach leaf. Transient expression of PpMYB10.4 in tobacco and peach leaves can induce anthocyain accumulation. Moreover, a functional MYB gene PpMYB10.2 on linkage group 3, which is homologous to PpMYB10.4, is also expressed in both red- and green-colored leaves, but plays no role in leaf red coloration. This suggests a complex mechanism underlying anthocyanin accumulation in peach leaf. In addition, PpMYB10.4 and other anthocyanin-activating MYB genes in Rosaceae responsible for anthocyanin accumulation in fruit are dated to a common ancestor about 70 million years ago (MYA). However, PpMYB10.4 has diverged from these anthocyanin-activating MYBs to generate a new gene family, which regulates anthocyanin accumulation in vegetative organs such as leaves. Activation of an ancient duplicated MYB gene PpMYB10.4 in the Gr interval on LG 6, which represents a novel branch of anthocyanin-activating MYB genes in Rosaceae, is able to activate leaf red coloration in peach.

78 citations


Cited by
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Journal ArticleDOI
TL;DR: A simplified model for the different regulatory networks involved with anthocyanin production in fruit is proposed and shows clear links between the developmental regulatory network and the specific regulators of anthcyanin biosynthesis during fruit ripening.

789 citations

Journal ArticleDOI
TL;DR: This review summarizes the current understanding of V-myb myeloblastosis viral oncogene homolog (MYB) proteins and their roles in the regulation of phenylpropanoid metabolism in plants.

569 citations

Journal Article
TL;DR: In this paper, the authors used gene specific primers to show that the three activators of apple anthocyanin (myb10/myb1/myBA) are likely alleles of each other.
Abstract: Background The control of plant anthocyanin accumulation is via transcriptional regulation of the genes encoding the biosynthetic enzymes. A key activator appears to be an R2R3 MYB transcription factor. In apple fruit, skin anthocyanin levels are controlled by a gene called MYBA or MYB1, while the gene determining fruit flesh and foliage anthocyanin has been termed MYB10. In order to further understand tissue-specific anthocyanin regulation we have isolated orthologous MYB genes from all the commercially important rosaceous species. Results We use gene specific primers to show that the three MYB activators of apple anthocyanin (MYB10/MYB1/MYBA) are likely alleles of each other. MYB transcription factors, with high sequence identity to the apple gene were isolated from across the rosaceous family (e.g. apples, pears, plums, cherries, peaches, raspberries, rose, strawberry). Key identifying amino acid residues were found in both the DNA-binding and C-terminal domains of these MYBs. The expression of these MYB10 genes correlates with fruit and flower anthocyanin levels. Their function was tested in tobacco and strawberry. In tobacco, these MYBs were shown to induce the anthocyanin pathway when co-expressed with bHLHs, while over-expression of strawberry and apple genes in the crop of origin elevates anthocyanins. Conclusions This family-wide study of rosaceous R2R3 MYBs provides insight into the evolution of this plant trait. It has implications for the development of new coloured fruit and flowers, as well as aiding the understanding of temporal-spatial colour change.

480 citations

Journal ArticleDOI
TL;DR: The data demonstrate that Cd perturbs the DNA methylation status through the involvement of a specific methyltransferase, linked to nuclear chromatin reconfiguration likely to establish a new balance of expressed/repressed chromatin.
Abstract: In mammals, cadmium is widely considered as a non-genotoxic carcinogen acting through a methylation-dependent epigenetic mechanism. Here, the effects of Cd treatment on the DNA methylation patten are examined together with its effect on chromatin reconfiguration in Posidonia oceanica. DNA methylation level and pattern were analysed in actively growing organs, under short- (6 h) and long- (2 d or 4 d) term and low (10 mM) and high (50 mM) doses of Cd, through a Methylation-Sensitive Amplification Polymorphism technique and an immunocytological approach, respectively. The expression of one member of the CHROMOMETHYLASE (CMT) family, a DNA methyltransferase, was also assessed by qRT-PCR. Nuclear chromatin ultrastructure was investigated by transmission electron microscopy. Cd treatment induced a DNA hypermethylation, as well as an up-regulation of CMT, indicating that de novo methylation did indeed occur. Moreover, a high dose of Cd led to a progressive heterochromatinization of interphase nuclei and apoptotic figures were also observed after long-term treatment. The data demonstrate that Cd perturbs the DNA methylation status through the involvement of a specific methyltransferase. Such changes are linked to nuclear chromatin reconfiguration likely to establish a new balance of expressed/repressed chromatin. Overall, the data show an epigenetic basis to the mechanism underlying Cd toxicity in plants.

450 citations

Journal ArticleDOI
TL;DR: Recent progress on elucidating the contribution of phenylpropanoid metabolism to the coordination of plant development and plant-environment interaction, and metabolic flux redirection among diverse metabolic routes are summarized.
Abstract: Phenylpropanoid metabolism is one of the most important metabolisms in plants, yielding more than 8,000 metabolites contributing to plant development and plant-environment interplay. Phenylpropanoid metabolism materialized during the evolution of early freshwater algae that were initiating terrestrialization and land plants have evolved multiple branches of this pathway, which give rise to metabolites including lignin, flavonoids, lignans, phenylpropanoid esters, hydroxycinnamic acid amides, and sporopollenin. Recent studies have revealed that many factors participate in the regulation of phenylpropanoid metabolism, and modulate phenylpropanoid homeostasis when plants undergo successive developmental processes and are subjected to stressful environments. In this review, we summarize recent progress on elucidating the contribution of phenylpropanoid metabolism to the coordination of plant development and plant-environment interaction, and metabolic flux redirection among diverse metabolic routes. In addition, our review focuses on the regulation of phenylpropanoid metabolism at the transcriptional, post-transcriptional, post-translational, and epigenetic levels, and in response to phytohormones and biotic and abiotic stresses.

345 citations