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Sample records for myb gene regulates

  1. MYB31/MYB42 Syntelogs Exhibit Divergent Regulation of Phenylpropanoid Genes in Maize, Sorghum and Rice

    PubMed Central

    Agarwal, Tina; Grotewold, Erich; Doseff, Andrea I.; Gray, John

    2016-01-01

    ZmMYB31 and ZmMYB42 are R2R3-MYB transcription factors implicated in the regulation of phenylpropanoid genes in maize. Here, we tested the hypothesis that the regulatory function of MYB31 and MYB42 is conserved in other monocots, specifically in sorghum and rice. We demonstrate that syntelogs of MYB31 and MYB42 do bind to phenylpropanoid genes that function in all stages of the pathway and in different tissues along the developmental gradient of seedling leaves. We found that caffeic acid O-methyltransferase (COMT1) is a common target of MYB31 and MYB42 in the mature leaf tissues of maize, sorghum and rice, as evidenced by Chromatin immunoprecipitation (ChIP) experiments. In contrast, 4-coumarate-CoA ligase (4CL2), ferulate-5-hydroxylase (F5H), and caffeoyl shikimate esterase (CSE), were targeted by MYB31 or MYB42, but in a more species-specific fashion. Our results revealed MYB31 and MYB42 participation in auto- and cross-regulation in all three species. Apart from a limited conservation of regulatory modules, MYB31 and MYB42 syntelogs appear to have undergone subfunctionalization following gene duplication and divergence of maize, sorghum, and rice. Elucidating the different regulatory roles of these syntelogs in the context of positive transcriptional activators may help guide attempts to alter the flux of intermediates towards lignin production in biofuel grasses. PMID:27328708

  2. Phenylpropanoids Accumulation in Eggplant Fruit: Characterization of Biosynthetic Genes and Regulation by a MYB Transcription Factor

    PubMed Central

    Docimo, Teresa; Francese, Gianluca; Ruggiero, Alessandra; Batelli, Giorgia; De Palma, Monica; Bassolino, Laura; Toppino, Laura; Rotino, Giuseppe L.; Mennella, Giuseppe; Tucci, Marina

    2016-01-01

    Phenylpropanoids are major secondary metabolites in eggplant (Solanum melongena) fruits. Chlorogenic acid (CGA) accounts for 70–90% of total phenolics in flesh tissues, while anthocyanins are mainly present in the fruit skin. As a contribution to the understanding of the peculiar accumulation of these health-promoting metabolites in eggplant, we report on metabolite abundance, regulation of CGA and anthocyanin biosynthesis, and characterization of candidate CGA biosynthetic genes in S. melongena. Higher contents of CGA, Delphinidin 3-rutinoside, and rutin were found in eggplant fruits compared to other tissues, associated to an elevated transcript abundance of structural genes such as PAL, HQT, DFR, and ANS, suggesting that active in situ biosynthesis contributes to anthocyanin and CGA accumulation in fruit tissues. Putative orthologs of the two CGA biosynthetic genes PAL and HQT, as well as a variant of a MYB1 transcription factor showing identity with group six MYBs, were isolated from an Occidental S. melongena traditional variety and demonstrated to differ from published sequences from Asiatic varieties. In silico analysis of the isolated SmPAL1, SmHQT1, SmANS, and SmMyb1 promoters revealed the presence of several Myb regulatory elements for the biosynthetic genes and unique elements for the TF, suggesting its involvement in other physiological roles beside phenylpropanoid biosynthesis regulation. Transient overexpression in Nicotiana benthamiana leaves of SmMyb1 and of a C-terminal SmMyb1 truncated form (SmMyb1Δ9) resulted in anthocyanin accumulation only of SmMyb1 agro-infiltrated leaves. A yeast two-hybrid assay confirmed the interaction of both SmMyb1 and SmMyb1Δ9 with an anthocyanin-related potato bHLH1 TF. Interestingly, a doubled amount of CGA was detected in both SmMyb1 and SmMyb1Δ9 agro-infiltrated leaves, thus suggesting that the N-terminal region of SmMyb1 is sufficient to activate its synthesis. These data suggest that a deletion of the C

  3. Phenylpropanoids Accumulation in Eggplant Fruit: Characterization of Biosynthetic Genes and Regulation by a MYB Transcription Factor.

    PubMed

    Docimo, Teresa; Francese, Gianluca; Ruggiero, Alessandra; Batelli, Giorgia; De Palma, Monica; Bassolino, Laura; Toppino, Laura; Rotino, Giuseppe L; Mennella, Giuseppe; Tucci, Marina

    2015-01-01

    Phenylpropanoids are major secondary metabolites in eggplant (Solanum melongena) fruits. Chlorogenic acid (CGA) accounts for 70-90% of total phenolics in flesh tissues, while anthocyanins are mainly present in the fruit skin. As a contribution to the understanding of the peculiar accumulation of these health-promoting metabolites in eggplant, we report on metabolite abundance, regulation of CGA and anthocyanin biosynthesis, and characterization of candidate CGA biosynthetic genes in S. melongena. Higher contents of CGA, Delphinidin 3-rutinoside, and rutin were found in eggplant fruits compared to other tissues, associated to an elevated transcript abundance of structural genes such as PAL, HQT, DFR, and ANS, suggesting that active in situ biosynthesis contributes to anthocyanin and CGA accumulation in fruit tissues. Putative orthologs of the two CGA biosynthetic genes PAL and HQT, as well as a variant of a MYB1 transcription factor showing identity with group six MYBs, were isolated from an Occidental S. melongena traditional variety and demonstrated to differ from published sequences from Asiatic varieties. In silico analysis of the isolated SmPAL1, SmHQT1, SmANS, and SmMyb1 promoters revealed the presence of several Myb regulatory elements for the biosynthetic genes and unique elements for the TF, suggesting its involvement in other physiological roles beside phenylpropanoid biosynthesis regulation. Transient overexpression in Nicotiana benthamiana leaves of SmMyb1 and of a C-terminal SmMyb1 truncated form (SmMyb1Δ9) resulted in anthocyanin accumulation only of SmMyb1 agro-infiltrated leaves. A yeast two-hybrid assay confirmed the interaction of both SmMyb1 and SmMyb1Δ9 with an anthocyanin-related potato bHLH1 TF. Interestingly, a doubled amount of CGA was detected in both SmMyb1 and SmMyb1Δ9 agro-infiltrated leaves, thus suggesting that the N-terminal region of SmMyb1 is sufficient to activate its synthesis. These data suggest that a deletion of the C

  4. Light-Induced Expression of a MYB Gene Regulates Anthocyanin Biosynthesis in Red Apples1

    PubMed Central

    Takos, Adam M.; Jaffé, Felix W.; Jacob, Steele R.; Bogs, Jochen; Robinson, Simon P.; Walker, Amanda R.

    2006-01-01

    Anthocyanins are secondary metabolites found in higher plants that contribute to the colors of flowers and fruits. In apples (Malus domestica Borkh.), several steps of the anthocyanin pathway are coordinately regulated, suggesting control by common transcription factors. A gene encoding an R2R3 MYB transcription factor was isolated from apple (cv Cripps' Pink) and designated MdMYB1. Analysis of the deduced amino acid sequence suggests that this gene encodes an ortholog of anthocyanin regulators in other plants. The expression of MdMYB1 in both Arabidopsis (Arabidopsis thaliana) plants and cultured grape cells induced the ectopic synthesis of anthocyanin. In the grape (Vitis vinifera) cells MdMYB1 stimulated transcription from the promoters of two apple genes encoding anthocyanin biosynthetic enzymes. In ripening apple fruit the transcription of MdMYB1 was correlated with anthocyanin synthesis in red skin sectors of fruit. When dark-grown fruit were exposed to sunlight, MdMYB1 transcript levels increased over several days, correlating with anthocyanin synthesis in the skin. MdMYB1 gene transcripts were more abundant in red skin apple cultivars compared to non-red skin cultivars. Several polymorphisms were identified in the promoter of MdMYB1. A derived cleaved amplified polymorphic sequence marker designed to one of these polymorphisms segregated with the inheritance of skin color in progeny from a cross of an unnamed red skin selection (a sibling of Cripps' Pink) and the non-red skin cultivar Golden Delicious. We conclude that MdMYB1 coordinately regulates genes in the anthocyanin pathway and the expression level of this regulator is the genetic basis for apple skin color. PMID:17012405

  5. A Myb transcription factor regulates genes of the phenylalanine pathway in maritime pine.

    PubMed

    Craven-Bartle, Blanca; Pascual, M Belen; Cánovas, Francisco M; Avila, Concepción

    2013-06-01

    During the life cycles of conifer trees, such as maritime pine (Pinus pinaster Ait.), large quantities of carbon skeletons are irreversibly immobilized in the wood. In energetic terms this is an expensive process, in which carbon from photosynthesis is channelled through the shikimate pathway for the biosynthesis of phenylpropanoids. This crucial metabolic pathway is finely regulated, primarily through transcriptional control, and because phenylalanine is the precursor for phenylpropanoid biosynthesis, the precise regulation of phenylalanine synthesis and use should occur simultaneously. The promoters of three genes encoding the enzymes prephenate aminotransferase (PAT), phenylalanine ammonia lyase (PAL) and glutamine synthetase (GS1b) contain AC elements involved in the transcriptional activation mediated by R2R3-Myb factors. We have examined the capacity of the R2R3-Myb transcription factors Myb1, Myb4 and Myb8 to co-regulate the expression of PAT, PAL and GS1b. Only Myb8 was able to activate the transcription of the three genes. Moreover, the expression of this transcription factor is higher in lignified tissues, in which a high demand for phenylpropanoids exits. In a gain-of-function experiment, we have shown that Myb8 can specifically bind a well-conserved eight-nucleotide-long AC-II element in the promoter regions of PAT, PAL and GS1b, thereby activating their expression. Our results show that Myb8 regulates the expression of these genes involved in phenylalanine metabolism, which is required for channelling photosynthetic carbon to promote wood formation. The co-localization of PAT, PAL, GS1b and MYB8 transcripts in vascular cells further supports this conclusion.

  6. Deep sequencing and in silico analyses identify MYB-regulated gene networks and signaling pathways in pancreatic cancer

    PubMed Central

    Azim, Shafquat; Zubair, Haseeb; Srivastava, Sanjeev K.; Bhardwaj, Arun; Zubair, Asif; Ahmad, Aamir; Singh, Seema; Khushman, Moh’d.; Singh, Ajay P.

    2016-01-01

    We have recently demonstrated that the transcription factor MYB can modulate several cancer-associated phenotypes in pancreatic cancer. In order to understand the molecular basis of these MYB-associated changes, we conducted deep-sequencing of transcriptome of MYB-overexpressing and -silenced pancreatic cancer cells, followed by in silico pathway analysis. We identified significant modulation of 774 genes upon MYB-silencing (p < 0.05) that were assigned to 25 gene networks by in silico analysis. Further analyses placed genes in our RNA sequencing-generated dataset to several canonical signalling pathways, such as cell-cycle control, DNA-damage and -repair responses, p53 and HIF1α. Importantly, we observed downregulation of the pancreatic adenocarcinoma signaling pathway in MYB-silenced pancreatic cancer cells exhibiting suppression of EGFR and NF-κB. Decreased expression of EGFR and RELA was validated by both qPCR and immunoblotting and they were both shown to be under direct transcriptional control of MYB. These observations were further confirmed in a converse approach wherein MYB was overexpressed ectopically in a MYB-null pancreatic cancer cell line. Our findings thus suggest that MYB potentially regulates growth and genomic stability of pancreatic cancer cells via targeting complex gene networks and signaling pathways. Further in-depth functional studies are warranted to fully understand MYB signaling in pancreatic cancer. PMID:27354262

  7. Deep sequencing and in silico analyses identify MYB-regulated gene networks and signaling pathways in pancreatic cancer.

    PubMed

    Azim, Shafquat; Zubair, Haseeb; Srivastava, Sanjeev K; Bhardwaj, Arun; Zubair, Asif; Ahmad, Aamir; Singh, Seema; Khushman, Moh'd; Singh, Ajay P

    2016-06-29

    We have recently demonstrated that the transcription factor MYB can modulate several cancer-associated phenotypes in pancreatic cancer. In order to understand the molecular basis of these MYB-associated changes, we conducted deep-sequencing of transcriptome of MYB-overexpressing and -silenced pancreatic cancer cells, followed by in silico pathway analysis. We identified significant modulation of 774 genes upon MYB-silencing (p < 0.05) that were assigned to 25 gene networks by in silico analysis. Further analyses placed genes in our RNA sequencing-generated dataset to several canonical signalling pathways, such as cell-cycle control, DNA-damage and -repair responses, p53 and HIF1α. Importantly, we observed downregulation of the pancreatic adenocarcinoma signaling pathway in MYB-silenced pancreatic cancer cells exhibiting suppression of EGFR and NF-κB. Decreased expression of EGFR and RELA was validated by both qPCR and immunoblotting and they were both shown to be under direct transcriptional control of MYB. These observations were further confirmed in a converse approach wherein MYB was overexpressed ectopically in a MYB-null pancreatic cancer cell line. Our findings thus suggest that MYB potentially regulates growth and genomic stability of pancreatic cancer cells via targeting complex gene networks and signaling pathways. Further in-depth functional studies are warranted to fully understand MYB signaling in pancreatic cancer.

  8. The MYB182 Protein Down-Regulates Proanthocyanidin and Anthocyanin Biosynthesis in Poplar by Repressing Both Structural and Regulatory Flavonoid Genes1[OPEN

    PubMed Central

    Yoshida, Kazuko; Ma, Dawei; Constabel, C. Peter

    2015-01-01

    Trees in the genus Populus (poplar) contain phenolic secondary metabolites including the proanthocyanidins (PAs), which help to adapt these widespread trees to diverse environments. The transcriptional activation of PA biosynthesis in response to herbivory and ultraviolet light stress has been documented in poplar leaves, and a regulator of this process, the R2R3-MYB transcription factor MYB134, has been identified. MYB134-overexpressing transgenic plants show a strong high-PA phenotype. Analysis of these transgenic plants suggested the involvement of additional MYB transcription factors, including repressor-like MYB factors. Here, MYB182, a subgroup 4 MYB factor, was found to act as a negative regulator of the flavonoid pathway. Overexpression of MYB182 in hairy root culture and whole poplar plants led to reduced PA and anthocyanin levels as well as a reduction in the expression of key flavonoid genes. Similarly, a reduced accumulation of transcripts of a MYB PA activator and a basic helix-loop-helix cofactor was observed in MYB182-overexpressing hairy roots. Transient promoter activation assays in poplar cell culture demonstrated that MYB182 can disrupt transcriptional activation by MYB134 and that the basic helix-loop-helix-binding motif of MYB182 was essential for repression. Microarray analysis of transgenic plants demonstrated that down-regulated targets of MYB182 also include shikimate pathway genes. This work shows that MYB182 plays an important role in the fine-tuning of MYB134-mediated flavonoid metabolism. PMID:25624398

  9. Epigenetic regulation of olfactory receptor gene expression by the Myb-MuvB/dREAM complex.

    PubMed

    Sim, Choon Kiat; Perry, Sarah; Tharadra, Sana Khalid; Lipsick, Joseph S; Ray, Anandasankar

    2012-11-15

    In both mammals and insects, an olfactory neuron will usually select a single olfactory receptor and repress remaining members of large receptor families. Here we show that a conserved multiprotein complex, Myb-MuvB (MMB)/dREAM, plays an important role in mediating neuron-specific expression of the carbon dioxide (CO(2)) receptor genes (Gr63a/Gr21a) in Drosophila. Activity of Myb in the complex is required for expression of Gr63a/Gr21a and acts in opposition to the histone methyltransferase Su(var)3-9. Consistent with this, we observed repressive dimethylated H3K9 modifications at the receptor gene loci, suggesting a mechanism for silencing receptor gene expression. Conversely, other complex members, Mip120 (Myb-interacting protein 120) and E2F2, are required for repression of Gr63a in inappropriate neurons. Misexpression in mutants is accompanied by an increase in the H3K4me3 mark of active chromatin at the receptor gene locus. Nuclei of CO(2) receptor-expressing neurons contain reduced levels of the repressive subunit Mip120 compared with surrounding neurons and increased levels of Myb, suggesting that activity of the complex can be regulated in a cell-specific manner. Our evidence suggests a model in which olfactory receptors are regulated epigenetically and the MMB/dREAM complex plays a critical role in specifying, maintaining, and modulating the receptor-to-neuron map.

  10. Ectopic Expression of the Coleus R2R3 MYB-Type Proanthocyanidin Regulator Gene SsMYB3 Alters the Flower Color in Transgenic Tobacco.

    PubMed

    Zhu, Qinlong; Sui, Shunzhao; Lei, Xinghua; Yang, Zhongfang; Lu, Kun; Liu, Guangde; Liu, Yao-Guang; Li, Mingyang

    2015-01-01

    Proanthocyanidins (PAs) play an important role in plant disease defense and have beneficial effects on human health. We isolated and characterized a novel R2R3 MYB-type PA-regulator SsMYB3 from a well-known ornamental plant, coleus (Solenostemon scutellarioides), to study the molecular regulation of PAs and to engineer PAs biosynthesis. The expression level of SsMYB3 was correlated with condensed tannins contents in various coleus tissues and was induced by wounding and light. A complementation test in the Arabidopsis tt2 mutant showed that SsMYB3 could restore the PA-deficient seed coat phenotype and activated expression of the PA-specific gene ANR and two related genes, DFR and ANS. In yeast two-hybrid assays, SsMYB3 interacted with the Arabidopsis AtTT8 and AtTTG1 to reform the ternary transcriptional complex, and also interacted with two tobacco bHLH proteins (NtAn1a and NtJAF13-1) and a WD40 protein, NtAn11-1. Ectopic overexpression of SsMYB3 in transgenic tobacco led to almost-white flowers by greatly reducing anthocyanin levels and enhancing accumulation of condensed tannins. This overexpression of SsMYB3 upregulated the key PA genes (NtLAR and NtANR) and late anthocyanin structural genes (NtDFR and NtANS), but downregulated the expression of the final anthocyanin gene NtUFGT. The formative SsMYB3-complex represses anthocyanin accumulation by directly suppressing the expression of the final anthocyanin structural gene NtUFGT, through competitive inhibition or destabilization of the endogenous NtAn2-complex formation. These results suggested that SsMYB3 may form a transcription activation complex to regulate PA biosynthesis in the Arabidopsis tt2 mutant and transgenic tobacco. Our findings suggest that SsMYB3 is involved in the regulation of PA biosynthesis in coleus and has the potential as a molecular tool for manipulating biosynthesis of PAs in fruits and other crops using metabolic engineering. PMID:26448466

  11. Ectopic Expression of the Coleus R2R3 MYB-Type Proanthocyanidin Regulator Gene SsMYB3 Alters the Flower Color in Transgenic Tobacco

    PubMed Central

    Zhu, Qinlong; Sui, Shunzhao; Lei, Xinghua; Yang, Zhongfang; Lu, Kun; Liu, Guangde; Liu, Yao-Guang; Li, Mingyang

    2015-01-01

    Proanthocyanidins (PAs) play an important role in plant disease defense and have beneficial effects on human health. We isolated and characterized a novel R2R3 MYB-type PA-regulator SsMYB3 from a well-known ornamental plant, coleus (Solenostemon scutellarioides), to study the molecular regulation of PAs and to engineer PAs biosynthesis. The expression level of SsMYB3 was correlated with condensed tannins contents in various coleus tissues and was induced by wounding and light. A complementation test in the Arabidopsis tt2 mutant showed that SsMYB3 could restore the PA-deficient seed coat phenotype and activated expression of the PA-specific gene ANR and two related genes, DFR and ANS. In yeast two-hybrid assays, SsMYB3 interacted with the Arabidopsis AtTT8 and AtTTG1 to reform the ternary transcriptional complex, and also interacted with two tobacco bHLH proteins (NtAn1a and NtJAF13-1) and a WD40 protein, NtAn11-1. Ectopic overexpression of SsMYB3 in transgenic tobacco led to almost-white flowers by greatly reducing anthocyanin levels and enhancing accumulation of condensed tannins. This overexpression of SsMYB3 upregulated the key PA genes (NtLAR and NtANR) and late anthocyanin structural genes (NtDFR and NtANS), but downregulated the expression of the final anthocyanin gene NtUFGT. The formative SsMYB3-complex represses anthocyanin accumulation by directly suppressing the expression of the final anthocyanin structural gene NtUFGT, through competitive inhibition or destabilization of the endogenous NtAn2-complex formation. These results suggested that SsMYB3 may form a transcription activation complex to regulate PA biosynthesis in the Arabidopsis tt2 mutant and transgenic tobacco. Our findings suggest that SsMYB3 is involved in the regulation of PA biosynthesis in coleus and has the potential as a molecular tool for manipulating biosynthesis of PAs in fruits and other crops using metabolic engineering. PMID:26448466

  12. Mutations in MYB3R1 and MYB3R4 cause pleiotropic developmental defects and preferential down-regulation of multiple G2/M-specific genes in Arabidopsis.

    PubMed

    Haga, Nozomi; Kobayashi, Kosuke; Suzuki, Takamasa; Maeo, Kenichiro; Kubo, Minoru; Ohtani, Misato; Mitsuda, Nobutaka; Demura, Taku; Nakamura, Kenzo; Jürgens, Gerd; Ito, Masaki

    2011-10-01

    R1R2R3-Myb proteins represent an evolutionarily conserved class of Myb family proteins important for cell cycle regulation and differentiation in eukaryotic cells. In plants, this class of Myb proteins are believed to regulate the transcription of G2/M phase-specific genes by binding to common cis-elements, called mitosis-specific activator (MSA) elements. In Arabidopsis (Arabidopsis thaliana), MYB3R1 and MYB3R4 act as transcriptional activators and positively regulate cytokinesis by activating the transcription of KNOLLE, which encodes a cytokinesis-specific syntaxin. Here, we show that the double mutation myb3r1 myb3r4 causes pleiotropic developmental defects, some of which are due to deficiency of KNOLLE whereas other are not, suggesting that multiple target genes are involved. Consistently, microarray analysis of the double mutant revealed altered expression of many genes, among which G2/M-specific genes showed significant overrepresentation of the MSA motif and a strong tendency to be down-regulated by the double mutation. Our results demonstrate, on a genome-wide level, the importance of the MYB3R-MSA pathway for regulating G2/M-specific transcription. In addition, MYB3R1 and MYB3R4 may have diverse roles during plant development by regulating G2/M-specific genes with various functions as well as genes possibly unrelated to the cell cycle.

  13. A Novel R2R3-MYB Transcription Factor BpMYB106 of Birch (Betula platyphylla) Confers Increased Photosynthesis and Growth Rate through Up-regulating Photosynthetic Gene Expression

    PubMed Central

    Zhou, Chenguang; Li, Chenghao

    2016-01-01

    We isolated a R2R3-MYB transcription factor BpMYB106, which regulates photosynthesis in birch (Betula platyphylla Suk.). BpMYB106 mainly expresses in the leaf and shoot tip of birch, and its protein is localized in the nucleus. We further fused isolated a 1588 bp promoter of BpMYB106 and analyzed it by PLACE, which showed some cis-acting elements related to photosynthesis. BpMYB106 promoter β-glucuronidase (GUS) reporter fusion studies gene, the result, showed the GUS reporter gene in transgenic birch with BpMYB106 promoter showed strong activities in shoot tip, cotyledon margins, and mature leaf trichomes. The overexpression of BpMYB106 in birch resulted in significantly increased trichome density, net photosynthetic rate, and growth rate as compared with the wild-type birch. RNA-Seq profiling revealed the upregulation of several photosynthesis-related genes in the photosynthesis and oxidative phosphorylation pathways in the leaves of transgenic plants. Yeast one-hybrid analysis, coupled with transient assay in tobacco, revealed that BpMYB106 binds a MYB binding site MYB2 in differentially expressed gene promoters. Thus, BpMYB106 may directly activate the expression of a range of photosynthesis related genes through interacting with the MYB2 element in their promoters. Our study demonstrating the overexpression of BpMYB106—a R2R3-MYB transcription factor—upregulates the genes of the photosynthesis and oxidative phosphorylation pathways to improve photosynthesis. PMID:27047502

  14. A Novel R2R3-MYB Transcription Factor BpMYB106 of Birch (Betula platyphylla) Confers Increased Photosynthesis and Growth Rate through Up-regulating Photosynthetic Gene Expression.

    PubMed

    Zhou, Chenguang; Li, Chenghao

    2016-01-01

    We isolated a R2R3-MYB transcription factor BpMYB106, which regulates photosynthesis in birch (Betula platyphylla Suk.). BpMYB106 mainly expresses in the leaf and shoot tip of birch, and its protein is localized in the nucleus. We further fused isolated a 1588 bp promoter of BpMYB106 and analyzed it by PLACE, which showed some cis-acting elements related to photosynthesis. BpMYB106 promoter β-glucuronidase (GUS) reporter fusion studies gene, the result, showed the GUS reporter gene in transgenic birch with BpMYB106 promoter showed strong activities in shoot tip, cotyledon margins, and mature leaf trichomes. The overexpression of BpMYB106 in birch resulted in significantly increased trichome density, net photosynthetic rate, and growth rate as compared with the wild-type birch. RNA-Seq profiling revealed the upregulation of several photosynthesis-related genes in the photosynthesis and oxidative phosphorylation pathways in the leaves of transgenic plants. Yeast one-hybrid analysis, coupled with transient assay in tobacco, revealed that BpMYB106 binds a MYB binding site MYB2 in differentially expressed gene promoters. Thus, BpMYB106 may directly activate the expression of a range of photosynthesis related genes through interacting with the MYB2 element in their promoters. Our study demonstrating the overexpression of BpMYB106-a R2R3-MYB transcription factor-upregulates the genes of the photosynthesis and oxidative phosphorylation pathways to improve photosynthesis. PMID:27047502

  15. A MYB/ZML Complex Regulates Wound-Induced Lignin Genes in Maize.

    PubMed

    Vélez-Bermúdez, Isabel-Cristina; Salazar-Henao, Jorge E; Fornalé, Silvia; López-Vidriero, Irene; Franco-Zorrilla, José-Manuel; Grotewold, Erich; Gray, John; Solano, Roberto; Schmidt, Wolfgang; Pagés, Montserrat; Riera, Marta; Caparros-Ruiz, David

    2015-11-01

    Lignin is an essential polymer in vascular plants that plays key structural roles in vessels and fibers. Lignification is induced by external inputs such as wounding, but the molecular mechanisms that link this stress to lignification remain largely unknown. In this work, we provide evidence that three maize (Zea mays) lignin repressors, MYB11, MYB31, and MYB42, participate in wound-induced lignification by interacting with ZML2, a protein belonging to the TIFY family. We determined that the three R2R3-MYB factors and ZML2 bind in vivo to AC-rich and GAT(A/C) cis-elements, respectively, present in a set of lignin genes. In particular, we show that MYB11 and ZML2 bind simultaneously to the AC-rich and GAT(A/C) cis-elements present in the promoter of the caffeic acid O-methyl transferase (comt) gene. We show that, like the R2R3-MYB factors, ZML2 also acts as a transcriptional repressor. We found that upon wounding and methyl jasmonate treatments, MYB11 and ZML2 proteins are degraded and comt transcription is induced. Based on these results, we propose a molecular regulatory mechanism involving a MYB/ZML complex in which wound-induced lignification can be achieved by the derepression of a set of lignin genes. PMID:26566917

  16. Transcriptional regulation of PIN genes by FOUR LIPS and MYB88 during Arabidopsis root gravitropism.

    PubMed

    Wang, Hong-Zhe; Yang, Ke-Zhen; Zou, Jun-Jie; Zhu, Ling-Ling; Xie, Zi Dian; Morita, Miyo Terao; Tasaka, Masao; Friml, Jiří; Grotewold, Erich; Beeckman, Tom; Vanneste, Steffen; Sack, Fred; Le, Jie

    2015-01-01

    PIN proteins are auxin export carriers that direct intercellular auxin flow and in turn regulate many aspects of plant growth and development including responses to environmental changes. The Arabidopsis R2R3-MYB transcription factor FOUR LIPS (FLP) and its paralogue MYB88 regulate terminal divisions during stomatal development, as well as female reproductive development and stress responses. Here we show that FLP and MYB88 act redundantly but differentially in regulating the transcription of PIN3 and PIN7 in gravity-sensing cells of primary and lateral roots. On the one hand, FLP is involved in responses to gravity stimulation in primary roots, whereas on the other, FLP and MYB88 function complementarily in establishing the gravitropic set-point angles of lateral roots. Our results support a model in which FLP and MYB88 expression specifically determines the temporal-spatial patterns of PIN3 and PIN7 transcription that are closely associated with their preferential functions during root responses to gravity. PMID:26578169

  17. Transcriptional regulation of PIN genes by FOUR LIPS and MYB88 during Arabidopsis root gravitropism

    PubMed Central

    Wang, Hong-Zhe; Yang, Ke-Zhen; Zou, Jun-Jie; Zhu, Ling-Ling; Xie, Zi Dian; Morita, Miyo Terao; Tasaka, Masao; Friml, Jiří; Grotewold, Erich; Beeckman, Tom; Vanneste, Steffen; Sack, Fred; Le, Jie

    2015-01-01

    PIN proteins are auxin export carriers that direct intercellular auxin flow and in turn regulate many aspects of plant growth and development including responses to environmental changes. The Arabidopsis R2R3-MYB transcription factor FOUR LIPS (FLP) and its paralogue MYB88 regulate terminal divisions during stomatal development, as well as female reproductive development and stress responses. Here we show that FLP and MYB88 act redundantly but differentially in regulating the transcription of PIN3 and PIN7 in gravity-sensing cells of primary and lateral roots. On the one hand, FLP is involved in responses to gravity stimulation in primary roots, whereas on the other, FLP and MYB88 function complementarily in establishing the gravitropic set-point angles of lateral roots. Our results support a model in which FLP and MYB88 expression specifically determines the temporal-spatial patterns of PIN3 and PIN7 transcription that are closely associated with their preferential functions during root responses to gravity. PMID:26578169

  18. A cotton gene encoding MYB-like transcription factor is specifically expressed in pollen and is involved in regulation of late anther/pollen development.

    PubMed

    Li, Yang; Jiang, Jia; Du, Man-Li; Li, Lan; Wang, Xiu-Lan; Li, Xue-Bao

    2013-06-01

    In flowering plants, pollen development is a highly programmed process, in which a lot of genes are involved. In this study, a gene, designated as GhMYB24, encoding R2R3-MYB-like protein was isolated from cotton. GhMYB24 protein is localized in the cell nucleus and acts as a transcriptional activator. Northern blot analysis revealed that GhMYB24 transcripts were predominantly detected in anthers. It was further found that strong expression of GhMYB24 was mainly detected in pollen and was regulated during anther development by in situ hybridization. Overexpression of GhMYB24 in Arabidopsis caused flower malformation, shorter filaments, non-dehiscent anthers and fewer viable pollen grains. Further analysis revealed that the septum and stomium cells of anthers were not broken, and fewer fibrous bands were found in the endothecium cells in transgenic plants. A complementation test demonstrated that GhMYB24 was able to recover partially the male fertility of the myb21 myb24 double mutant. Expression levels of the genes involved in the phenylpropanoid biosynthetic pathway and reactive oxygen species homeostasis were altered in GhMYB24-overexpressing transgenic plants. Furthermore, the genes involved in jasmonate biosynthesis and its signaling pathway were up-regulated in the transgenic plants. Yeast two-hybrid assay indicated that GhMYB24 interacted with GhJAZ1/2 in cells. Taking the data together, our results suggest that GhMYB24 may play an important role in normal anther/pollen development.

  19. Four genes encoding MYB28, a major transcriptional regulator of the aliphatic glucosinolate pathway, are differentially expressed in the allopolyploid Brassica juncea.

    PubMed

    Augustine, Rehna; Majee, Manoj; Gershenzon, Jonathan; Bisht, Naveen C

    2013-11-01

    Glucosinolates are Capparales-specific secondary metabolites that have immense potential in human health and agriculture. Unlike Arabidopsis thaliana, our knowledge about glucosinolate regulators in the Brassica crops is sparse. In the current study, four MYB28 homologues were identified (BjuMYB28-1,-2,-3,-4) from the polyploid Brassica juncea, and the effects of allopolyploidization on the divergence of gene sequence, structure, function, and expression were assessed. The deduced protein sequences of the four BjuMYB28 genes showed 76.1-83.1% identity with the Arabidopsis MYB28. Phylogenetic analysis revealed that the four BjuMYB28 proteins have evolved via the hybridization and duplication processes forming the B. juncea genome (AABB) from B. rapa (AA) and B. nigra (BB), while retaining high levels of sequence conservation. Mutant complementation and over-expression studies in A. thaliana showed that all four BjuMYB28 genes encode functional MYB28 proteins and resulted in similar aliphatic glucosinolate composition and content. Detailed expression analysis using qRT-PCR assays and promoter-GUS lines revealed that the BjuMYB28 genes have both tissue- and cell-specific expression partitioning in B. juncea. The two B-genome origin BjuMYB28 genes had more abundant transcripts during the early stages of plant development than the A-genome origin genes. However, with the onset of the reproductive phase, expression levels of all four BjuMYB28 increased significantly, which may be necessary for producing and maintaining high amounts of aliphatic glucosinolates during the later stages of plant development. Taken together, our results suggest that the four MYB28 genes are differentially expressed and regulated in B. juncea to play discrete though overlapping roles in controlling aliphatic glucosinolate biosynthesis.

  20. Four genes encoding MYB28, a major transcriptional regulator of the aliphatic glucosinolate pathway, are differentially expressed in the allopolyploid Brassica juncea.

    PubMed

    Augustine, Rehna; Majee, Manoj; Gershenzon, Jonathan; Bisht, Naveen C

    2013-11-01

    Glucosinolates are Capparales-specific secondary metabolites that have immense potential in human health and agriculture. Unlike Arabidopsis thaliana, our knowledge about glucosinolate regulators in the Brassica crops is sparse. In the current study, four MYB28 homologues were identified (BjuMYB28-1,-2,-3,-4) from the polyploid Brassica juncea, and the effects of allopolyploidization on the divergence of gene sequence, structure, function, and expression were assessed. The deduced protein sequences of the four BjuMYB28 genes showed 76.1-83.1% identity with the Arabidopsis MYB28. Phylogenetic analysis revealed that the four BjuMYB28 proteins have evolved via the hybridization and duplication processes forming the B. juncea genome (AABB) from B. rapa (AA) and B. nigra (BB), while retaining high levels of sequence conservation. Mutant complementation and over-expression studies in A. thaliana showed that all four BjuMYB28 genes encode functional MYB28 proteins and resulted in similar aliphatic glucosinolate composition and content. Detailed expression analysis using qRT-PCR assays and promoter-GUS lines revealed that the BjuMYB28 genes have both tissue- and cell-specific expression partitioning in B. juncea. The two B-genome origin BjuMYB28 genes had more abundant transcripts during the early stages of plant development than the A-genome origin genes. However, with the onset of the reproductive phase, expression levels of all four BjuMYB28 increased significantly, which may be necessary for producing and maintaining high amounts of aliphatic glucosinolates during the later stages of plant development. Taken together, our results suggest that the four MYB28 genes are differentially expressed and regulated in B. juncea to play discrete though overlapping roles in controlling aliphatic glucosinolate biosynthesis. PMID:24043856

  1. The R3-MYB Gene GhCPC Negatively Regulates Cotton Fiber Elongation

    PubMed Central

    Liu, Bingliang; Zhu, Yichao; Zhang, Tianzhen

    2015-01-01

    Cotton (Gossypium spp.) fibers are single-cell trichomes that arise from the outer epidermal layer of seed coat. Here, we isolated a R3-MYB gene GhCPC, identified by cDNA microarray analysis. The only conserved R3 motif and different expression between TM-1 and fuzzless-lintless mutants suggested that it might be a negative regulator in fiber development. Transgenic evidence showed that GhCPC overexpression not only delayed fiber initiation but also led to significant decreases in fiber length. Interestingly, Yeast two-hybrid analysis revealed an interaction complex, in which GhCPC and GhTTG1/4 separately interacted with GhMYC1. In transgenic plants, Q-PCR analysis showed that GhHOX3 (GL2) and GhRDL1 were significantly down regulated in −1–5 DPA ovules and fibers. In addition, Yeast one-hybrid analysis demonstrated that GhMYC1 could bind to the E-box cis-elements and the promoter of GhHOX3. These results suggested that GhHOX3 (GL2) might be downstream gene of the regulatory complex. Also, overexpression of GhCPC in tobacco led to differential loss of pigmentation. Taken together, the results suggested that GhCPC might negatively regulate cotton fiber initiation and early elongation by a potential CPC-MYC1-TTG1/4 complex. Although the fibers were shorter in transgenic cotton lines than in the wild type, no significant difference was detected in stem or leaf trichomes, even in cotton mutants (five naked seed or fuzzless), suggesting that fiber and trichome development might be regulated by two sets of genes sharing a similar model. PMID:25646816

  2. The wheat R2R3-MYB transcription factor TaRIM1 participates in resistance response against the pathogen Rhizoctonia cerealis infection through regulating defense genes

    PubMed Central

    Shan, Tianlei; Rong, Wei; Xu, Huijun; Du, Lipu; Liu, Xin; Zhang, Zengyan

    2016-01-01

    The necrotrophic fungus Rhizoctonia cerealis is a major pathogen of sharp eyespot that is a devastating disease of wheat (Triticum aestivum). Little is known about roles of MYB genes in wheat defense response to R. cerealis. In this study, TaRIM1, a R. cerealis-induced wheat MYB gene, was identified by transcriptome analysis, then cloned from resistant wheat CI12633, and its function and preliminary mechanism were studied. Sequence analysis showed that TaRIM1 encodes a R2R3-MYB transcription factor with transcription-activation activity. The molecular-biological assays revealed that the TaRIM1 protein localizes to nuclear and can bind to five MYB-binding site cis-elements. Functional dissection results showed that following R. cerealis inoculation, TaRIM1 silencing impaired the resistance of wheat CI12633, whereas TaRIM1 overexpression significantly increased resistance of transgenic wheat compared with susceptible recipient. TaRIM1 positively regulated the expression of five defense genes (Defensin, PR10, PR17c, nsLTP1, and chitinase1) possibly through binding to MYB-binding sites in their promoters. These results suggest that the R2R3-MYB transcription factor TaRIM1 positively regulates resistance response to R. cerealis infection through modulating the expression of a range of defense genes, and that TaRIM1 is a candidate gene to improve sharp eyespot resistance in wheat. PMID:27364458

  3. Subspecialization of R2R3-MYB Repressors for Anthocyanin and Proanthocyanidin Regulation in Forage Legumes

    PubMed Central

    Albert, Nick W.

    2015-01-01

    The synthesis of anthocyanin pigments and proanthocyanidins (condensed tannins) is regulated by MYB-bHLH-WDR (MBW) transcription factor complexes in all angiosperms studied to date. Tr-MYB133 and Tr-MYB134 were isolated from Trifolium repens and encode R2R3-MYBs that antagonize the activity of MBW activation complexes. These two genes are conserved in other legume species, and form two sub-clades within the larger anthocyanin/proanthocyanidin clade of MYB repressors. However, unlike petunia and Arabidopsis, these R2R3-MYB repressors do not prevent ectopic accumulation of anthocyanins or proanthocyanidins. Instead, they are expressed when anthocyanins or proanthocyanidins are being synthesized, and provide feedback regulation to MBW complexes. This feedback occurs because Tr-MYB133 and Tr-MYB134 are themselves regulated by MBW complexes. Tr-MYB133 is regulated by MBW complexes containing anthocyanin-related R2R3-MYB proteins (Tr-RED LEAF), while Tr-MYB134 is regulated by complexes containing the proanthocyanidin R2R3-MYBs (Tr-MYB14). Other features of the MBW gene regulation networks are also conserved within legumes, including the ability for the anthocyanin MBW complexes to activate the expression of the AN1/TT8 clade bHLH factor. The regulation of Tr-MYB133 and Tr-MYB134 by distinct, pathway-specific MBW complexes has resulted in subspecialization for controlling anthocyanin or proanthocyanidin synthesis. PMID:26779194

  4. MYB3Rs, plant homologs of Myb oncoproteins, control cell cycle-regulated transcription and form DREAM-like complexes.

    PubMed

    Kobayashi, Kosuke; Suzuki, Toshiya; Iwata, Eriko; Magyar, Zoltán; Bögre, László; Ito, Masaki

    2015-01-01

    Plant MYB3R transcription factors, homologous to Myb oncoproteins, regulate the genes expressed at G2 and M phases in the cell cycle. Recent studies showed that MYB3Rs constitute multiprotein complexes that may correspond to animal complexes known as DREAM or dREAM. Discovery of the putative homologous complex in plants uncovered their significant varieties in structure, function, dynamics, and heterogeneity, providing insight into conserved and diversified aspects of cell cycle-regulated gene transcription.

  5. Transcriptional regulation of an iron-inducible gene by differential and alternate promoter entries of multiple Myb proteins in the protozoan parasite Trichomonas vaginalis.

    PubMed

    Hsu, Hong-Ming; Ong, Shiou-Jeng; Lee, Ming-Chun; Tai, Jung-Hsiang

    2009-03-01

    Iron-inducible transcription of a malic enzyme gene (also reputed to be ap65-1) in Trichomonas vaginalis was previously shown to involve a Myb1 repressor and a Myb2 activator, each of which may preferentially select two closely spaced promoter sites, MRE-1/MRE-2r, which comprises overlapping promoter elements, and MRE-2f. In the present study, an iron-inducible approximately 32-kDa Myb3 nuclear protein was demonstrated to bind only the MRE-1 element. Changes in the iron supply, which produced antagonistic effects on the levels of Myb2 and Myb3 expression, also resulted in temporal and alternate entries of Myb2 and Myb3 into the ap65-1 promoter. Repression or activation of basal and iron-inducible ap65-1 transcription was detected in transfected cells when Myb3 was, respectively, substantially knocked down or overexpressed. In the latter case, increased Myb3 promoter entry was detected with concomitant decrease in Myb2 promoter entry under specific conditions, while Myb3 promoter entry was inhibited under all test conditions in cells overexpressing Myb2. In contrast, concomitant promoter entries by Myb2 and Myb3 diminished in cells overexpressing Myb1, except that Myb3 promoter entry was slightly affected under prolonged iron depletion. Together, these results suggest that Myb2 and Myb3 may coactivate basal and iron-inducible ap65-1 transcription against Myb1 through conditional and competitive promoter entries. PMID:19151329

  6. Two LcbHLH Transcription Factors Interacting with LcMYB1 in Regulating Late Structural Genes of Anthocyanin Biosynthesis in Nicotiana and Litchi chinensis During Anthocyanin Accumulation

    PubMed Central

    Lai, Biao; Du, Li-Na; Liu, Rui; Hu, Bing; Su, Wen-Bing; Qin, Yong-Hua; Zhao, Jie-Tang; Wang, Hui-Cong; Hu, Gui-Bing

    2016-01-01

    Anthocyanin biosynthesis requires the MYB-bHLH-WD40 protein complex to activate the late biosynthetic genes. LcMYB1 was thought to act as key regulator in anthocyanin biosynthesis of litchi. However, basic helix-loop-helix proteins (bHLHs) as partners have not been identified yet. The present study describes the functional characterization of three litchi bHLH candidate anthocyanin regulators, LcbHLH1, LcbHLH2, and LcbHLH3. Although these three litchi bHLHs phylogenetically clustered with bHLH proteins involved in anthcoyanin biosynthesis in other plant, only LcbHLH1 and LcbHLH3 were found to localize in the nucleus and physically interact with LcMYB1. The transcription levels of all these bHLHs were not coordinated with anthocyanin accumulation in different tissues and during development. However, when co-infiltrated with LcMYB1, both LcbHLH1 and LcbHLH3 enhanced anthocyanin accumulation in tobacco leaves with LcbHLH3 being the best inducer. Significant accumulation of anthocyanins in leaves transformed with the combination of LcMYB1 and LcbHLH3 were noticed, and this was associated with the up-regulation of two tobacco endogenous bHLH regulators, NtAn1a and NtAn1b, and late structural genes, like NtDFR and NtANS. Significant activity of the ANS promoter was observed in transient expression assays either with LcMYB1-LcbHLH1 or LcMYB1-LcbHLH3, while only minute activity was detected after transformation with only LcMYB1. In contrast, no activity was measured after induction with the combination of LcbHLH2 and LcMYB1. Higher DFR expression was also oberseved in paralleling with higher anthocyanins in co-transformed lines. LcbHLH1 and LcbHLH3 are essential partner of LcMYB1 in regulating the anthocyanin production in tobacco and probably also in litchi. The LcMYB1-LcbHLH complex enhanced anthocyanin accumulation may associate with activating the transcription of DFR and ANS. PMID:26925082

  7. Two LcbHLH Transcription Factors Interacting with LcMYB1 in Regulating Late Structural Genes of Anthocyanin Biosynthesis in Nicotiana and Litchi chinensis During Anthocyanin Accumulation.

    PubMed

    Lai, Biao; Du, Li-Na; Liu, Rui; Hu, Bing; Su, Wen-Bing; Qin, Yong-Hua; Zhao, Jie-Tang; Wang, Hui-Cong; Hu, Gui-Bing

    2016-01-01

    Anthocyanin biosynthesis requires the MYB-bHLH-WD40 protein complex to activate the late biosynthetic genes. LcMYB1 was thought to act as key regulator in anthocyanin biosynthesis of litchi. However, basic helix-loop-helix proteins (bHLHs) as partners have not been identified yet. The present study describes the functional characterization of three litchi bHLH candidate anthocyanin regulators, LcbHLH1, LcbHLH2, and LcbHLH3. Although these three litchi bHLHs phylogenetically clustered with bHLH proteins involved in anthcoyanin biosynthesis in other plant, only LcbHLH1 and LcbHLH3 were found to localize in the nucleus and physically interact with LcMYB1. The transcription levels of all these bHLHs were not coordinated with anthocyanin accumulation in different tissues and during development. However, when co-infiltrated with LcMYB1, both LcbHLH1 and LcbHLH3 enhanced anthocyanin accumulation in tobacco leaves with LcbHLH3 being the best inducer. Significant accumulation of anthocyanins in leaves transformed with the combination of LcMYB1 and LcbHLH3 were noticed, and this was associated with the up-regulation of two tobacco endogenous bHLH regulators, NtAn1a and NtAn1b, and late structural genes, like NtDFR and NtANS. Significant activity of the ANS promoter was observed in transient expression assays either with LcMYB1-LcbHLH1 or LcMYB1-LcbHLH3, while only minute activity was detected after transformation with only LcMYB1. In contrast, no activity was measured after induction with the combination of LcbHLH2 and LcMYB1. Higher DFR expression was also oberseved in paralleling with higher anthocyanins in co-transformed lines. LcbHLH1 and LcbHLH3 are essential partner of LcMYB1 in regulating the anthocyanin production in tobacco and probably also in litchi. The LcMYB1-LcbHLH complex enhanced anthocyanin accumulation may associate with activating the transcription of DFR and ANS. PMID:26925082

  8. The soybean R2R3 MYB transcription factor GmMYB100 negatively regulates plant flavonoid biosynthesis.

    PubMed

    Yan, Junhui; Wang, Biao; Zhong, Yunpeng; Yao, Luming; Cheng, Linjing; Wu, Tianlong

    2015-09-01

    Soybean flavonoids, a group of important signaling molecules in plant-environment interaction, ubiquitously exist in soybean and are tightly regulated by many genes. Here we reported that GmMYB100, a gene encoding a R2R3 MYB transcription factor, is involved in soybean flavonoid biosynthesis. GmMYB100 is mainly expressed in flowers, leaves and immature embryo, and its level is decreased after pod ripening. Subcellular localization assay indicates that GmMYB100 is a nuclear protein. GmMYB100 has transactivation ability revealed by a yeast functional assay; whereas bioinformatic analysis suggests that GmMYB100 has a negative function in flavonoid biosynthesis. GmMYB100-overexpression represses the transcript levels of flavonoid-related genes in transgenic soybean hairy roots and Arabidopsis, and inhibits isoflavonoid (soybean) and flavonol (Arabidopsis) production in transgenic plants. Furthermore, the transcript levels of six flavonoid-related genes and flavonoid (isoflavonoid and flavone aglycones) accumulation are elevated in the GmMYB100-RNAi transgenic hairy roots. We also demonstrate that GmMYB100 protein depresses the promoter activities of soybean chalcone synthase and chalcone isomerase. These findings indicate that GmMYB100 is a negative regulator in soybean flavonoid biosynthesis pathway.

  9. Multiple R2R3-MYB Transcription Factors Involved in the Regulation of Anthocyanin Accumulation in Peach Flower

    PubMed Central

    Zhou, Hui; Peng, Qian; Zhao, Jianbo; Owiti, Albert; Ren, Fei; Liao, Liao; Wang, Lu; Deng, Xianbao; Jiang, Quan; Han, Yuepeng

    2016-01-01

    Anthocyanin accumulation is responsible for flower coloration in peach. Here, we report the identification and functional characterization of eight flavonoid-related R2R3-MYB transcription factors, designated PpMYB10.2, PpMYB9, PpMYBPA1, Peace, PpMYB17, PpMYB18, PpMYB19, and PpMYB20, respectively, in peach flower transcriptome. PpMYB10.2 and PpMYB9 are able to activate transcription of anthocyanin biosynthetic genes, whilst PpMYBPA1 and Peace have a strong activation on the promoters of proanthocyanin (PA) biosynthetic genes. PpMYB17-20 show a strong repressive effect on transcription of flavonoid pathway genes such as dihydroflavonol 4-reductase. These results indicate that anthocyanin accumulation in peach flower is coordinately regulated by a set of R2R3-MYB genes. In addition, PpMYB9 and PpMYB10.2 are closely related but separated into two groups, designated MYB9 and MYB10, respectively. PpMYB9 shows a strong activation on the PpUGT78A2 promoter, but with no effect on the promoter of PpUGT78B (commonly called PpUFGT in previous studies). In contrast, PpMYB10.2 is able to activate the PpUFGT promoter, but not for the PpUGT78A2 promoter. Unlike the MYB10 gene that is universally present in plants, the MYB9 gene is lost in most dicot species. Therefore, the PpMYB9 gene represents a novel group of anthocyanin-related MYB activators, which may have diverged in function from the MYB10 genes. Our study will aid in understanding the complex mechanism regulating floral pigmentation in peach and functional divergence of the R2R3-MYB gene family in plants.

  10. Identification of a R2R3-MYB gene regulating anthocyanin biosynthesis and relationships between its variation and flower color difference in lotus (Nelumbo Adans.).

    PubMed

    Sun, Shan-Shan; Gugger, Paul F; Wang, Qing-Feng; Chen, Jin-Ming

    2016-01-01

    The lotus (Nelumbonaceae: Nelumbo Adans.) is a highly desired ornamental plant, comprising only two extant species, the sacred lotus (N. nucifera Gaerten.) with red flowers and the American lotus (N. lutea Willd.) with yellow flowers. Flower color is the most obvious difference of two species. To better understand the mechanism of flower color differentiation, the content of anthocyanins and the expression levels of four key structural genes (e.g., DFR, ANS, UFGT and GST) were analyzed in two species. Our results revealed that anthocyanins were detected in red flowers, not yellow flowers. Expression analysis showed that no transcripts of GST gene and low expression level of three UFGT genes were detected in yellow flowers. In addition, three regulatory genes (NnMYB5, NnbHLH1 and NnTTG1) were isolated from red flowers and showed a high similarity to corresponding regulatory genes of other species. Sequence analysis of MYB5, bHLH1 and TTG1 in two species revealed striking differences in coding region and promoter region of MYB5 gene. Population analysis identified three MYB5 variants in Nelumbo: a functional allele existed in red flowers and two inactive forms existed in yellow flowers. This result revealed that there was an association between allelic variation in MYB5 gene and flower color difference. Yeast two-hybrid experiments showed that NnMYB5 interacts with NnbHLH1, NlbHLH1 and NnTTG1, and NnTTG1 also interacts with NnbHLH1 and NlbHLH1. The over-expression of NnMYB5 led to anthocyanin accumulation in immature seeds and flower stalks and up-regulation of expression of TT19 in Arabidopsis. Therefore, NnMYB5 is a transcription activator of anthocyanin synthesis. This study helps to elucidate the function of NnMYB5 and will contribute to clarify the mechanism of flower coloration and genetic engineering of flower color in lotus.

  11. Identification of a R2R3-MYB gene regulating anthocyanin biosynthesis and relationships between its variation and flower color difference in lotus (Nelumbo Adans.)

    PubMed Central

    Sun, Shan-Shan

    2016-01-01

    The lotus (Nelumbonaceae: Nelumbo Adans.) is a highly desired ornamental plant, comprising only two extant species, the sacred lotus (N. nucifera Gaerten.) with red flowers and the American lotus (N. lutea Willd.) with yellow flowers. Flower color is the most obvious difference of two species. To better understand the mechanism of flower color differentiation, the content of anthocyanins and the expression levels of four key structural genes (e.g., DFR, ANS, UFGT and GST) were analyzed in two species. Our results revealed that anthocyanins were detected in red flowers, not yellow flowers. Expression analysis showed that no transcripts of GST gene and low expression level of three UFGT genes were detected in yellow flowers. In addition, three regulatory genes (NnMYB5, NnbHLH1 and NnTTG1) were isolated from red flowers and showed a high similarity to corresponding regulatory genes of other species. Sequence analysis of MYB5, bHLH1 and TTG1 in two species revealed striking differences in coding region and promoter region of MYB5 gene. Population analysis identified three MYB5 variants in Nelumbo: a functional allele existed in red flowers and two inactive forms existed in yellow flowers. This result revealed that there was an association between allelic variation in MYB5 gene and flower color difference. Yeast two-hybrid experiments showed that NnMYB5 interacts with NnbHLH1, NlbHLH1 and NnTTG1, and NnTTG1 also interacts with NnbHLH1 and NlbHLH1. The over-expression of NnMYB5 led to anthocyanin accumulation in immature seeds and flower stalks and up-regulation of expression of TT19 in Arabidopsis. Therefore, NnMYB5 is a transcription activator of anthocyanin synthesis. This study helps to elucidate the function of NnMYB5 and will contribute to clarify the mechanism of flower coloration and genetic engineering of flower color in lotus. PMID:27635336

  12. Identification of a R2R3-MYB gene regulating anthocyanin biosynthesis and relationships between its variation and flower color difference in lotus (Nelumbo Adans.)

    PubMed Central

    Sun, Shan-Shan

    2016-01-01

    The lotus (Nelumbonaceae: Nelumbo Adans.) is a highly desired ornamental plant, comprising only two extant species, the sacred lotus (N. nucifera Gaerten.) with red flowers and the American lotus (N. lutea Willd.) with yellow flowers. Flower color is the most obvious difference of two species. To better understand the mechanism of flower color differentiation, the content of anthocyanins and the expression levels of four key structural genes (e.g., DFR, ANS, UFGT and GST) were analyzed in two species. Our results revealed that anthocyanins were detected in red flowers, not yellow flowers. Expression analysis showed that no transcripts of GST gene and low expression level of three UFGT genes were detected in yellow flowers. In addition, three regulatory genes (NnMYB5, NnbHLH1 and NnTTG1) were isolated from red flowers and showed a high similarity to corresponding regulatory genes of other species. Sequence analysis of MYB5, bHLH1 and TTG1 in two species revealed striking differences in coding region and promoter region of MYB5 gene. Population analysis identified three MYB5 variants in Nelumbo: a functional allele existed in red flowers and two inactive forms existed in yellow flowers. This result revealed that there was an association between allelic variation in MYB5 gene and flower color difference. Yeast two-hybrid experiments showed that NnMYB5 interacts with NnbHLH1, NlbHLH1 and NnTTG1, and NnTTG1 also interacts with NnbHLH1 and NlbHLH1. The over-expression of NnMYB5 led to anthocyanin accumulation in immature seeds and flower stalks and up-regulation of expression of TT19 in Arabidopsis. Therefore, NnMYB5 is a transcription activator of anthocyanin synthesis. This study helps to elucidate the function of NnMYB5 and will contribute to clarify the mechanism of flower coloration and genetic engineering of flower color in lotus.

  13. Identification of a R2R3-MYB gene regulating anthocyanin biosynthesis and relationships between its variation and flower color difference in lotus (Nelumbo Adans.).

    PubMed

    Sun, Shan-Shan; Gugger, Paul F; Wang, Qing-Feng; Chen, Jin-Ming

    2016-01-01

    The lotus (Nelumbonaceae: Nelumbo Adans.) is a highly desired ornamental plant, comprising only two extant species, the sacred lotus (N. nucifera Gaerten.) with red flowers and the American lotus (N. lutea Willd.) with yellow flowers. Flower color is the most obvious difference of two species. To better understand the mechanism of flower color differentiation, the content of anthocyanins and the expression levels of four key structural genes (e.g., DFR, ANS, UFGT and GST) were analyzed in two species. Our results revealed that anthocyanins were detected in red flowers, not yellow flowers. Expression analysis showed that no transcripts of GST gene and low expression level of three UFGT genes were detected in yellow flowers. In addition, three regulatory genes (NnMYB5, NnbHLH1 and NnTTG1) were isolated from red flowers and showed a high similarity to corresponding regulatory genes of other species. Sequence analysis of MYB5, bHLH1 and TTG1 in two species revealed striking differences in coding region and promoter region of MYB5 gene. Population analysis identified three MYB5 variants in Nelumbo: a functional allele existed in red flowers and two inactive forms existed in yellow flowers. This result revealed that there was an association between allelic variation in MYB5 gene and flower color difference. Yeast two-hybrid experiments showed that NnMYB5 interacts with NnbHLH1, NlbHLH1 and NnTTG1, and NnTTG1 also interacts with NnbHLH1 and NlbHLH1. The over-expression of NnMYB5 led to anthocyanin accumulation in immature seeds and flower stalks and up-regulation of expression of TT19 in Arabidopsis. Therefore, NnMYB5 is a transcription activator of anthocyanin synthesis. This study helps to elucidate the function of NnMYB5 and will contribute to clarify the mechanism of flower coloration and genetic engineering of flower color in lotus. PMID:27635336

  14. Molecular characterization of BrMYB28 and BrMYB29 paralogous transcription factors involved in the regulation of aliphatic glucosinolate profiles in Brassica rapa ssp. pekinensis.

    PubMed

    Baskar, Venkidasamy; Park, Se Won

    2015-07-01

    Glucosinolates (GSL) are one of the major secondary metabolites of the Brassicaceae family. In the present study, we aim at characterizing the multiple paralogs of aliphatic GSL regulators, such as BrMYB28 and BrMYB29 genes in Brassica rapa ssp. pekinensis, by quantitative real-time PCR (qRT-PCR) analysis in different tissues and at various developmental stages. An overlapping gene expression pattern between the BrMYBs as well as their downstream genes (DSGs) was found at different developmental stages. Among the BrMYB28 and BrMYB29 paralogous genes, the BrMYB28.3 and BrMYB29.1 genes were dominantly expressed in most of the developmental stages, compared to the other paralogs of the BrMYB genes. Furthermore, the differential expression pattern of the BrMYBs was observed under various stress treatments. Interestingly, BrMYB28.2 showed the least expression in most developmental stages, while its expression was remarkably high in different stress conditions. More specifically, the BrMYB28.2, BrMYB28.3, and BrMYB29.1 genes were highly responsive to various abiotic and biotic stresses, further indicating their possible role in stress tolerance. Moreover, the in silico cis motif analysis in the upstream regulatory regions of BrMYBs showed the presence of various putative stress-specific motifs, which further indicated their responsiveness to biotic and abiotic stresses. These observations suggest that the dominantly expressed BrMYBs, both in different developmental stages and under various stress treatments (BrMYB28.3 and BrMYB29.1), may be potential candidate genes for altering the GSL level through genetic modification studies in B. rapa ssp. pekinensis.

  15. Molecular characterization of BrMYB28 and BrMYB29 paralogous transcription factors involved in the regulation of aliphatic glucosinolate profiles in Brassica rapa ssp. pekinensis.

    PubMed

    Baskar, Venkidasamy; Park, Se Won

    2015-07-01

    Glucosinolates (GSL) are one of the major secondary metabolites of the Brassicaceae family. In the present study, we aim at characterizing the multiple paralogs of aliphatic GSL regulators, such as BrMYB28 and BrMYB29 genes in Brassica rapa ssp. pekinensis, by quantitative real-time PCR (qRT-PCR) analysis in different tissues and at various developmental stages. An overlapping gene expression pattern between the BrMYBs as well as their downstream genes (DSGs) was found at different developmental stages. Among the BrMYB28 and BrMYB29 paralogous genes, the BrMYB28.3 and BrMYB29.1 genes were dominantly expressed in most of the developmental stages, compared to the other paralogs of the BrMYB genes. Furthermore, the differential expression pattern of the BrMYBs was observed under various stress treatments. Interestingly, BrMYB28.2 showed the least expression in most developmental stages, while its expression was remarkably high in different stress conditions. More specifically, the BrMYB28.2, BrMYB28.3, and BrMYB29.1 genes were highly responsive to various abiotic and biotic stresses, further indicating their possible role in stress tolerance. Moreover, the in silico cis motif analysis in the upstream regulatory regions of BrMYBs showed the presence of various putative stress-specific motifs, which further indicated their responsiveness to biotic and abiotic stresses. These observations suggest that the dominantly expressed BrMYBs, both in different developmental stages and under various stress treatments (BrMYB28.3 and BrMYB29.1), may be potential candidate genes for altering the GSL level through genetic modification studies in B. rapa ssp. pekinensis. PMID:26043798

  16. EjMYB8 Transcriptionally Regulates Flesh Lignification in Loquat Fruit.

    PubMed

    Wang, Wen-Qiu; Zhang, Jing; Ge, Hang; Li, Shao-Jia; Li, Xian; Yin, Xue-Ren; Grierson, Donald; Chen, Kun-Song

    2016-01-01

    Transcriptional regulatory mechanisms underlying lignin metabolism have been widely studied in model plants and woody trees, but seldom in fruits such as loquat, which undergo lignification. Here, twelve EjMYB genes, designed as EjMYB3-14, were isolated based on RNA-seq. Gene expression indicated that EjMYB8 and EjMYB9 were significantly induced in fruit with higher lignin content resulting from storage at low temperature (0°C), while two treatments (low temperature conditioning, LTC; heat treatment, HT) both alleviated fruit lignification and inhibited EjMYB8 and EjMYB9 expression. Dual-luciferase assays indicated that EjMYB8, but not EjMYB9, could trans-activate promoters of lignin-related genes EjPAL1, Ej4CL1 and Ej4CL5. Yeast one-hybrid assay indicated that EjMYB8 physically bind to Ej4CL1 promoter. Furthermore, the putative functions of EjMYB8 were verified using transient over-expression in both N. tabacum and loquat leaves, which increased lignin content. Moreover, combination of EjMYB8 and previously isolated EjMYB1 generated strong trans-activation effects on the Ej4CL1 promoter, indicating that EjMYB8 is a novel regulator of loquat fruit lignification. PMID:27111303

  17. EjMYB8 Transcriptionally Regulates Flesh Lignification in Loquat Fruit

    PubMed Central

    Ge, Hang; Li, Shao-jia; Li, Xian; Yin, Xue-ren; Grierson, Donald; Chen, Kun-song

    2016-01-01

    Transcriptional regulatory mechanisms underlying lignin metabolism have been widely studied in model plants and woody trees, but seldom in fruits such as loquat, which undergo lignification. Here, twelve EjMYB genes, designed as EjMYB3-14, were isolated based on RNA-seq. Gene expression indicated that EjMYB8 and EjMYB9 were significantly induced in fruit with higher lignin content resulting from storage at low temperature (0°C), while two treatments (low temperature conditioning, LTC; heat treatment, HT) both alleviated fruit lignification and inhibited EjMYB8 and EjMYB9 expression. Dual-luciferase assays indicated that EjMYB8, but not EjMYB9, could trans-activate promoters of lignin-related genes EjPAL1, Ej4CL1 and Ej4CL5. Yeast one-hybrid assay indicated that EjMYB8 physically bind to Ej4CL1 promoter. Furthermore, the putative functions of EjMYB8 were verified using transient over-expression in both N. tabacum and loquat leaves, which increased lignin content. Moreover, combination of EjMYB8 and previously isolated EjMYB1 generated strong trans-activation effects on the Ej4CL1 promoter, indicating that EjMYB8 is a novel regulator of loquat fruit lignification. PMID:27111303

  18. Control of plant trichome development by a cotton fiber MYB gene.

    PubMed

    Wang, Shui; Wang, Jia-Wei; Yu, Nan; Li, Chun-Hong; Luo, Bin; Gou, Jin-Ying; Wang, Ling-Jian; Chen, Xiao-Ya

    2004-09-01

    Cotton (Gossypium spp) plants produce seed trichomes (cotton fibers) that are an important commodity worldwide; however, genes controlling cotton fiber development have not been characterized. In Arabidopsis thaliana the MYB gene GLABRA1 (GL1) is a central regulator of trichome development. Here, we show that promoter of a cotton fiber gene, RD22-like1 (RDL1), contains a homeodomain binding L1 box and a MYB binding motif that confer trichome-specific expression in Arabidopsis. A cotton MYB protein GaMYB2/Fiber Factor 1 transactivated the RDL1 promoter both in yeast and in planta. Real-time PCR and in situ analysis showed that GaMYB2 is predominantly expressed early in developing cotton fibers. After transferring into Arabidopsis, GL1::GaMYB2 rescued trichome formation of a gl1 mutant, and interestingly, 35S::GaMYB2 induced seed-trichome production. We further demonstrate that the first intron of both GL1 and GaMYB2 plays a role in patterning trichomes: it acts as an enhancer in trichome and a repressor in nontrichome cells, generating a trichome-specific pattern of MYB gene expression. Disruption of a MYB motif conserved in intron 1 of GL1, WEREWOLF, and GaMYB2 genes affected trichome production. These results suggest that cotton and Arabidopsis use similar transcription factors for regulating trichomes and that GaMYB2 may be a key regulator of cotton fiber development.

  19. MYB transcription factors regulate glucosinolate biosynthesis in different organs of Chinese cabbage (Brassica rapa ssp. pekinensis).

    PubMed

    Kim, Yeon Bok; Li, Xiaohua; Kim, Sun-Ju; Kim, Haeng Hoon; Lee, Jeongyeo; Kim, HyeRan; Park, Sang Un

    2013-07-22

    In this study, we investigated the expression of seven MYB transcription factors (a total of 17 genes that included Dof1.1, IQD1-1, MYB28, MYB29, MYB34, MYB51, and MYB122 and their isoforms) involved in aliphatic and indolic glucosinolate (GSL) biosynthesis and analyzed the aliphatic and indolic GSL content in different organs of Chinese cabbage (Brassica rapassp. Pekinensis). MYB28 and MYB29 expression in the stem was dramatically different when compared with the levels in the other organs. MYB34, MYB122, MYB51, Dof1.1, and IQD1-1 showed very low transcript levels among different organs. HPLC analysis showed that the glucosinolates (GSLs) consisted of five aliphatic GSLs (progoitrin, sinigrin, glucoalyssin, gluconapin, and glucobrassicanapin) and four indolic GSLs (4-hydroxyglucobrassicin, glucobrassicin, 4-methoxygluco-brassicin, and neoglucobrassicin). Aliphatic GSLs exhibited 63.3% of the total GSLs content, followed by aromatic GSL (19.0%), indolic GSLs (10%), and unknown GSLs (7.7%) in different organs of Chinese cabbage. The total GSL content of different parts (ranked in descending order) was as follows: seed > flower > young leaves > stem > root > old leaves. The relationship between GSLs accumulation and expression of GSLs biosynthesis MYB TFs genes in different organs may be helpful to understand the mechanism of MYB TFs regulating GSL biosynthesis in Chinese cabbage.

  20. The Woody-Preferential Gene EgMYB88 Regulates the Biosynthesis of Phenylpropanoid-Derived Compounds in Wood

    PubMed Central

    Soler, Marçal; Plasencia, Anna; Lepikson-Neto, Jorge; Camargo, Eduardo L. O.; Dupas, Annabelle; Ladouce, Nathalie; Pesquet, Edouard; Mounet, Fabien; Larbat, Romain; Grima-Pettenati, Jacqueline

    2016-01-01

    Comparative phylogenetic analyses of the R2R3-MYB transcription factor family revealed that five subgroups were preferentially found in woody species and were totally absent from Brassicaceae and monocots (Soler et al., 2015). Here, we analyzed one of these subgroups (WPS-I) for which no gene had been yet characterized. Most Eucalyptus members of WPS-I are preferentially expressed in the vascular cambium, the secondary meristem responsible for tree radial growth. We focused on EgMYB88, which is the most specifically and highly expressed in vascular tissues, and showed that it behaves as a transcriptional activator in yeast. Then, we functionally characterized EgMYB88 in both transgenic Arabidopsis and poplar plants overexpressing either the native or the dominant repression form (fused to the Ethylene-responsive element binding factor-associated Amphiphilic Repression motif, EAR). The transgenic Arabidopsis lines had no phenotype whereas the poplar lines overexpressing EgMYB88 exhibited a substantial increase in the levels of the flavonoid catechin and of some salicinoid phenolic glycosides (salicortin, salireposide, and tremulacin), in agreement with the increase of the transcript levels of landmark biosynthetic genes. A change in the lignin structure (increase in the syringyl vs. guaiacyl, S/G ratio) was also observed. Poplar lines overexpressing the EgMYB88 dominant repression form did not show a strict opposite phenotype. The level of catechin was reduced, but the levels of the salicinoid phenolic glycosides and the S/G ratio remained unchanged. In addition, they showed a reduction in soluble oligolignols containing sinapyl p-hydroxybenzoate accompanied by a mild reduction of the insoluble lignin content. Altogether, these results suggest that EgMYB88, and more largely members of the WPS-I group, could control in cambium and in the first layers of differentiating xylem the biosynthesis of some phenylpropanoid-derived secondary metabolites including lignin. PMID

  1. The R2R3-MYB Transcription Factors MYB14 and MYB15 Regulate Stilbene Biosynthesis in Vitis vinifera[W

    PubMed Central

    Höll, Janine; Vannozzi, Alessandro; Czemmel, Stefan; D'Onofrio, Claudio; Walker, Amanda R.; Rausch, Thomas; Lucchin, Margherita; Boss, Paul K.; Dry, Ian B.; Bogs, Jochen

    2013-01-01

    Plant stilbenes are phytoalexins that accumulate in a small number of plant species, including grapevine (Vitis vinifera), in response to biotic and abiotic stresses and have been implicated in many beneficial effects on human health. In particular, resveratrol, the basic unit of all other complex stilbenes, has received widespread attention because of its cardio-protective, anticarcinogenic, and antioxidant properties. Although stilbene synthases (STSs), the key enzymes responsible for resveratrol biosynthesis, have been isolated and characterized from several plant species, the transcriptional regulation underlying stilbene biosynthesis is unknown. Here, we report the identification and functional characterization of two R2R3-MYB–type transcription factors (TFs) from grapevine, which regulate the stilbene biosynthetic pathway. These TFs, designated MYB14 and MYB15, strongly coexpress with STS genes, both in leaf tissues under biotic and abiotic stress and in the skin and seed of healthy developing berries during maturation. In transient gene reporter assays, MYB14 and MYB15 were demonstrated to specifically activate the promoters of STS genes, and the ectopic expression of MYB15 in grapevine hairy roots resulted in increased STS expression and in the accumulation of glycosylated stilbenes in planta. These results demonstrate the involvement of MYB14 and MYB15 in the transcriptional regulation of stilbene biosynthesis in grapevine. PMID:24151295

  2. MYB80, a regulator of tapetal and pollen development, is functionally conserved in crops.

    PubMed

    Phan, Huy A; Li, Song F; Parish, Roger W

    2012-01-01

    The Arabidopsis AtMYB80 transcription factor (formerly AtMYB103) regulate genes essential for tapetal and pollen development. One of these genes, coding for an aspartic protease (UNDEAD), may control the timing of tapetal programmed cell death (PCD). In crop plants such as rice and wheat, abiotic stresses lead to abnormal tapetal development resulting in delayed PCD. Manipulation of AtMYB80 function has been used to develop a reversible male sterility system applicable to hybrid crop production. MYB80 homologs were cloned from wheat, rice, canola and cotton. The promoters of the homologs drove temporal and spatial expression patterns of the GUS reporter gene in the tapetum and microspores of Arabidopsis anthers identical to the AtMYB80 promoter. A short region is conserved in all five MYB80 promoters. The MYB80 homolog genes, driven by the AtMYB80 or their respective promoters, rescued the atmyb80 mutant, completely restoring male fertility. The canola MYB80 was fused to the EAR (ERF-associated amphiphilic repression) repressor and canola plants transgenic for the construct exhibited premature tapetal degradation and subsequent pollen abortion. The five MYB80 homologs all shared a 44 amino acid sequence immediately adjacent to the R2R3 domain which appears to be necessary for MYB80 function.

  3. Three R2R3-MYB transcription factors regulate distinct floral pigmentation patterning in Phalaenopsis spp.

    PubMed

    Hsu, Chia-Chi; Chen, You-Yi; Tsai, Wen-Chieh; Chen, Wen-Huei; Chen, Hong-Hwa

    2015-05-01

    Orchidaceae are well known for their fascinating floral morphologic features, specialized pollination, and distinctive ecological strategies. With their long-lasting flowers of various colors and pigmentation patterning, Phalaenopsis spp. have become important ornamental plants worldwide. In this study, we identified three R2R3-MYB transcription factors PeMYB2, PeMYB11, and PeMYB12. Their expression profiles were concomitant with red color formation in Phalaenopsis spp. flowers. Transient assay of overexpression of three PeMYBs verified that PeMYB2 resulted in anthocyanin accumulation, and these PeMYBs could activate the expression of three downstream structural genes Phalaenopsis spp. Flavanone 3-hydroxylase5, Phalaenopsis spp. Dihydroflavonol 4-reductase1, and Phalaenopsis spp. Anthocyanidin synthase3. In addition, these three PeMYBs participated in the distinct pigmentation patterning in a single flower, which was revealed by virus-induced gene silencing. In the sepals/petals, silencing of PeMYB2, PeMYB11, and PeMYB12 resulted in the loss of the full-red pigmentation, red spots, and venation patterns, respectively. Moreover, different pigmentation patterning was regulated by PeMYBs in the sepals/petals and lip. PeMYB11 was responsive to the red spots in the callus of the lip, and PeMYB12 participated in the full pigmentation in the central lobe of the lip. The differential pigmentation patterning was validated by RNA in situ hybridization. Additional assessment was performed in six Phalaenopsis spp. cultivars with different color patterns. The combined expression of these three PeMYBs in different ratios leads to a wealth of complicated floral pigmentation patterning in Phalaenopsis spp.

  4. BrMYB4, a suppressor of genes for phenylpropanoid and anthocyanin biosynthesis, is down-regulated by UV-B but not by pigment-inducing sunlight in turnip cv. Tsuda.

    PubMed

    Zhang, Lili; Wang, Yu; Sun, Mei; Wang, Jing; Kawabata, Saneyuki; Li, Yuhua

    2014-12-01

    The regulation of light-dependent anthocyanin biosynthesis in Brassica rapa subsp. rapa cv. Tsuda turnip was investigated using an ethyl methanesulfonate (EMS)-induced mutant R30 with light-independent pigmentation. TILLING (targeting induced local lesions in genomes) and subsequent analysis showed that a stop codon was inserted in the R2R3-MYB transcription factor gene BrMYB4 and that the encoded protein (BrMYB4mu) had lost its C-terminal region. In R30, anthocyanin accumulated in the below-ground portion of the storage root of 2-month-old plants. In 4-day-old seedlings and 2-month-old plants, expression of BrMYB4 was similar between R30 and the wild type (WT), but the expression of the cinnamate 4-hydroxylase gene (BrC4H) was markedly enhanced in R30 in the dark. In turnip seedlings, BrMYB4 expression was suppressed by UV-B irradiation in the WT, but this negative regulation was absent in R30. Concomitantly, BrC4H was repressed by UV-B irradiation in the WT, but stayed at high levels in R30. A gel-shift assay revealed that BrMYB4 could directly bind to the promoter region of BrC4H, but BrMYB4mu could not. The BrMYB4-enhanced green fluorescent protein (eGFP) protein could enter the nucleus in the presence of BrSAD2 (an importin β-like protein) nuclear transporter, but BrMYB4mu-eGFP could not. These results showed that BrMYB4 functions as a negative transcriptional regulator of BrC4H and mediates UV-B-dependent phenylpropanoid biosynthesis, while BrMYB4mu has lost this function. In the storage roots, the expression of anthocyanin biosynthesis genes was enhanced in R30 in the dark and in sunlight in both the WT and R30. However, in the WT, anthocyanin-inducing sunlight did not suppress BrMYB4 expression. Therefore, sunlight-induced anthocyanin biosynthesis does not seem to be regulated by BrMYB4.

  5. BrMYB4, a suppressor of genes for phenylpropanoid and anthocyanin biosynthesis, is down-regulated by UV-B but not by pigment-inducing sunlight in turnip cv. Tsuda.

    PubMed

    Zhang, Lili; Wang, Yu; Sun, Mei; Wang, Jing; Kawabata, Saneyuki; Li, Yuhua

    2014-12-01

    The regulation of light-dependent anthocyanin biosynthesis in Brassica rapa subsp. rapa cv. Tsuda turnip was investigated using an ethyl methanesulfonate (EMS)-induced mutant R30 with light-independent pigmentation. TILLING (targeting induced local lesions in genomes) and subsequent analysis showed that a stop codon was inserted in the R2R3-MYB transcription factor gene BrMYB4 and that the encoded protein (BrMYB4mu) had lost its C-terminal region. In R30, anthocyanin accumulated in the below-ground portion of the storage root of 2-month-old plants. In 4-day-old seedlings and 2-month-old plants, expression of BrMYB4 was similar between R30 and the wild type (WT), but the expression of the cinnamate 4-hydroxylase gene (BrC4H) was markedly enhanced in R30 in the dark. In turnip seedlings, BrMYB4 expression was suppressed by UV-B irradiation in the WT, but this negative regulation was absent in R30. Concomitantly, BrC4H was repressed by UV-B irradiation in the WT, but stayed at high levels in R30. A gel-shift assay revealed that BrMYB4 could directly bind to the promoter region of BrC4H, but BrMYB4mu could not. The BrMYB4-enhanced green fluorescent protein (eGFP) protein could enter the nucleus in the presence of BrSAD2 (an importin β-like protein) nuclear transporter, but BrMYB4mu-eGFP could not. These results showed that BrMYB4 functions as a negative transcriptional regulator of BrC4H and mediates UV-B-dependent phenylpropanoid biosynthesis, while BrMYB4mu has lost this function. In the storage roots, the expression of anthocyanin biosynthesis genes was enhanced in R30 in the dark and in sunlight in both the WT and R30. However, in the WT, anthocyanin-inducing sunlight did not suppress BrMYB4 expression. Therefore, sunlight-induced anthocyanin biosynthesis does not seem to be regulated by BrMYB4. PMID:25305244

  6. MybA1 gene diversity across the Vitis genus.

    PubMed

    Péros, Jean-Pierre; Launay, Amandine; Berger, Gilles; Lacombe, Thierry; This, Patrice

    2015-06-01

    The MybA1 gene in the genus Vitis encodes a transcription factor, belonging to the R2R3 Myb family, that controls the last steps in the anthocyanins biosynthesis pathway. Polymorphism within MybA1 has been associated with color variation in berries of V. vinifera and other Vitis species. In this work, we analyzed the sequence variation in MybA1 both in the subg. Muscadinia and in an extended set of Asian, American and European genotypes of subg. Vitis. Our aims were to infer the evolution of this gene during the speciation process and to identify polymorphisms that could potentially generate changes in gene regulation. The results show that MybA1 experienced many insertions and deletions in non-coding regions but also in the third exon sequence. Owing to the larger set of Vitis species compared here, new indels were identified and the origin of previously described indels was reconsidered. A large number of single nucleotide polymorphisms were found in non-coding regions but also in the sequence coding for the R2R3 domain and the C terminal part of the protein. Some of these changes led to amino acid substitutions and therefore could have modified MybA1 protein activity. Bayesian phylogenetic analysis of all polymorphisms did not provide a consensus tree depicting the geographical partitioning of the species but allowed highlighting several species relationships within subgenus Vitis. Finally, the evolutionary events described could be useful to gain more insight into the role of MybA1 for anthocyanin biosynthesis in grapevine.

  7. Two MYB transcription factors regulate flavonoid biosynthesis in pear fruit (Pyrus bretschneideri Rehd.).

    PubMed

    Zhai, Rui; Wang, Zhimin; Zhang, Shiwei; Meng, Geng; Song, Linyan; Wang, Zhigang; Li, Pengmin; Ma, Fengwang; Xu, Lingfei

    2016-03-01

    Flavonoid compounds play important roles in the modern diet, and pear fruits are an excellent dietary source of these metabolites. However, information on the regulatory network of flavonoid biosynthesis in pear fruits is rare. In this work, 18 putative flavonoid-related MYB transcription factors (TFs) were screened by phylogenetic analysis and four of them were correlated with flavonoid biosynthesis patterns in pear fruits. Among these MYB-like genes, the specific functions of two novel MYB TFs, designated as PbMYB10b and PbMYB9, were further verified by both overexpression and RNAi transient assays. PbMYB10b, a PAP-type MYB TF with atypical motifs in its conserved region, regulated the anthocyanin and proanthocyanidin pathways by inducing the expression of PbDFR, but its function could be complemented by other MYB TFs. PbMYB9, a TT2-type MYB, not only acted as the specific activator of the proanthocyanidin pathway by activating the PbANR promoter, but also induced the synthesis of anthocyanins and flavonols by binding the PbUFGT1 promoter in pear fruits. The MYBCORE-like element has been identified in both the PbUFGT1 promoter and ANR promoters in most species, but it was not found in UFGT promoters isolated from other species. This finding was also supported by a yeast one-hybrid assay and thus enhanced the likelihood of the interaction between PbMYB9 and the PbUFGT1 promoter.

  8. The RB-related gene Rb2/p130 in neuroblastoma differentiation and in B-myb promoter down-regulation.

    PubMed

    Raschellà, G; Tanno, B; Bonetto, F; Negroni, A; Claudio, P P; Baldi, A; Amendola, R; Calabretta, B; Giordano, A; Paggi, M G

    1998-05-01

    The retinoblastoma family of nuclear factors is composed of RB, the prototype of the tumour suppressor genes and of the strictly related genes p107 and Rb2/p130. The three genes code for proteins, namely pRb, p107 and pRb2/p130, that share similar structures and functions. These proteins are expressed, often simultaneously, in many cell types and are involved in the regulation of proliferation and differentiation. We determined the expression and the phosphorylation of the RB family gene products during the DMSO-induced differentiation of the N1E-115 murine neuroblastoma cells. In this system, pRb2/p130 was strongly up-regulated during mid-late differentiation stages, while, on the contrary, pRb and p107 resulted markedly decreased at late stages. Differentiating N1E-115 cells also showed a progressive decrease in B-myb levels, a proliferation-related protein whose constitutive expression inhibits neuronal differentiation. Transfection of each of the RB family genes in these cells was able, at different degrees, to induce neuronal differentiation, to inhibit [3H]thymidine incorporation and to down-regulate the activity of the B-myb promoter.

  9. Functional divergence of MYB-related genes, WEREWOLF and AtMYB23 in Arabidopsis.

    PubMed

    Tominaga-Wada, Rumi; Nukumizu, Yuka; Sato, Shusei; Kato, Tomohiko; Tabata, Satoshi; Wada, Takuji

    2012-01-01

    Epidermal cell differentiation in Arabidopsis is studied as a model system to understand the mechanisms that determine the developmental end state of plant cells. MYB-related transcription factors are involved in cell fate determination. To examine the molecular basis of this process, we analyzed the functional relationship of two R2R3-type MYB genes, AtMYB23 (MYB23) and WEREWOLF (WER). MYB23 is involved in leaf trichome formation. WER represses root-hair formation. Swapping domains between MYB23 and WER, we found that a low homology region of MYB23 might be involved in ectopic trichome initiation on hypocotyls. MYB23 and all MYB23-WER (MW) chimeric transgenes rescued the increased root-hair phenotype of the wer-1 mutant. Although WER did not rescue the gl1-1 no-trichome phenotype, MYB23 and all MW chimeric transgenes rescued gl1-1. These results suggest that MYB23 acquired a specific function for trichome differentiation during evolution.

  10. The MYB23 gene provides a positive feedback loop for cell fate specification in the Arabidopsis root epidermis.

    PubMed

    Kang, Yeon Hee; Kirik, Victor; Hulskamp, Martin; Nam, Kyoung Hee; Hagely, Katherine; Lee, Myeong Min; Schiefelbein, John

    2009-04-01

    The specification of cell fates during development requires precise regulatory mechanisms to ensure robust cell type patterns. Theoretical models of pattern formation suggest that a combination of negative and positive feedback mechanisms are necessary for efficient specification of distinct fates in a field of differentiating cells. Here, we examine the role of the R2R3-MYB transcription factor gene, AtMYB23 (MYB23), in the establishment of the root epidermal cell type pattern in Arabidopsis thaliana. MYB23 is closely related to, and is positively regulated by, the WEREWOLF (WER) MYB gene during root epidermis development. Furthermore, MYB23 is able to substitute for the function of WER and to induce its own expression when controlled by WER regulatory sequences. We also show that the MYB23 protein binds to its own promoter, suggesting a MYB23 positive feedback loop. The localization of MYB23 transcripts and MYB23-green fluorescent protein (GFP) fusion protein, as well as the effect of a chimeric MYB23-SRDX repressor construct, links MYB23 function to the developing non-hair cell type. Using mutational analyses, we find that MYB23 is necessary for precise establishment of the root epidermal pattern, particularly under conditions that compromise the cell specification process. These results suggest that MYB23 participates in a positive feedback loop to reinforce cell fate decisions and ensure robust establishment of the cell type pattern in the Arabidopsis root epidermis.

  11. c-Myb influences HIV type 1 gene expression and virus production.

    PubMed

    Churchill, M J; Ramsay, R G; Rhodes, D I; Deacon, N J

    2001-11-01

    c-Myb is expressed in proliferating T cells. Fifteen c-Myb-binding sites can be identified in the HIV-1 long terminal repeat (LTR), suggesting that c-Myb may regulate HIV-1 gene expression and virus replication. Increasing the cellular levels of c-Myb by transient transfection of CEM cells resulted in a 10- to 20-fold activation of HIV-1 LTR-driven gene expression and mutation of one high-affinity Myb-binding site within the LTR reduced this activation by 60 to 70%. Conversely, inhibition of c-Myb expression in MT-2 cells by treatment with c-myb antisense oligonucleotides decreased HIV-1 replication by 85%, as measured by reverse transcriptase activity and cytopathic effects. The effect of c-myb antisense oligonucleotides on HIV-1 gene expression and virus particle production appeared to be independent of cell proliferation, but dependent on the presence of c-Myb activity mediated through the HIV-1 LTR. These data show that c-myb expression affects HIV-1 replication in CD4(+) T cells.

  12. Molecular characterization of the Jatropha curcas JcR1MYB1 gene encoding a putative R1-MYB transcription factor

    PubMed Central

    Li, Hui-Liang; Guo, Dong; Peng, Shi-Qing

    2014-01-01

    The cDNA encoding the R1-MYB transcription factor, designated as JcR1MYB1, was isolated from Jatropha curcas using rapid amplification of cDNA ends. JcR1MYB1 contains a 951 bp open reading frame that encodes 316 amino acids. The deduced JcR1MYB1 protein was predicted to possess the conserved, 56-amino acid-long DNA-binding domain, which consists of a single helix-turn-helix module and usually occurs in R1-MYBs. JcR1MYB1 is a member of the R1-MYB transcription factor subfamily. A subcellular localization study confirmed the nuclear localization of JcR1MYB1. Expression analysis showed that JcR1MYB1 transcripts accumulated in various examined tissues, with high expression levels in the root and low levels in the stem. JcR1MYB1 transcription was up-regulated by polyethylene glycol, NaCl, and cold treatments, as well as by abscisic acid, jasmonic acid, and ethylene treatment. Analysis of transgenic tobacco plants over-expressing JcR1MYB1 indicates an inportant function for this gene in salt stress. PMID:25249778

  13. Regulation of secondary cell wall biosynthesis by poplar R2R3 MYB transcription factor PtrMYB152 in Arabidopsis

    SciTech Connect

    Wang, Shucai; Li, Eryang; Porth, Ilga; Chen, Jin-Gui; Mansfield, Shawn D.; Douglas, Carl

    2014-05-23

    Poplar has 192 annotated R2R3 MYB genes, of which only three have been shown to play a role in the regulation of secondary cell wall formation. Here we report the characterization of PtrMYB152, a poplar homolog of the Arabidopsis R2R3 MYB transcription factor AtMYB43, in the regulation of secondary cell wall biosynthesis. The expression of PtrMYB152 in secondary xylem is about 18 times of that in phloem. When expressed in Arabidopsis under the control of either 35S or PtrCesA8 promoters, PtrMYB152 increased secondary cell wall thickness, which is likely caused by increased lignification. Accordingly, elevated expression of genes encoding sets of enzymes in secondary wall biosynthesis were observed in transgenic plants expressing PtrMYB152. Arabidopsis protoplast transfection assays suggested that PtrMYB152 functions as a transcriptional activator. Taken together, our results suggest that PtrMYB152 may be part of a regulatory network activating expression of discrete sets of secondary cell wall biosynthesis genes.

  14. Regulation of secondary cell wall biosynthesis by poplar R2R3 MYB transcription factor PtrMYB152 in Arabidopsis

    PubMed Central

    Wang, Shucai; Li, Eryang; Porth, Ilga; Chen, Jin-Gui; Mansfield, Shawn D.; Douglas, Carl J.

    2014-01-01

    Poplar has 192 annotated R2R3 MYB genes, of which only three have been shown to play a role in the regulation of secondary cell wall formation. Here we report the characterization of PtrMYB152, a poplar homolog of the Arabidopsis R2R3 MYB transcription factor AtMYB43, in the regulation of secondary cell wall biosynthesis. The expression of PtrMYB152 in secondary xylem is about 18 times of that in phloem. When expressed in Arabidopsis under the control of either 35S or PtrCesA8 promoters, PtrMYB152 increased secondary cell wall thickness, which is likely caused by increased lignification. Accordingly, elevated expression of genes encoding sets of enzymes in secondary wall biosynthesis were observed in transgenic plants expressing PtrMYB152. Arabidopsis protoplast transfection assays suggested that PtrMYB152 functions as a transcriptional activator. Taken together, our results suggest that PtrMYB152 may be part of a regulatory network activating expression of discrete sets of secondary cell wall biosynthesis genes. PMID:24852237

  15. A MYB transcription factor regulates anthocyanin biosynthesis in mangosteen (Garcinia mangostana L.) fruit during ripening.

    PubMed

    Palapol, Yossapol; Ketsa, Saichol; Lin-Wang, Kui; Ferguson, Ian B; Allan, Andrew C

    2009-05-01

    Mangosteen (Garcinia mangostana L.) fruit undergo rapid red colour development, both on the tree and after harvest, resulting in high anthocyanin production in the pericarp. Here, we report the isolation of three full-length mangosteen MYB transcription factors (GmMYB1, GmMYB7 and GmMYB10) and all the anthocyanin biosynthetic pathway genes (GmPal to GmUFGT). Phylogenetic analysis at the protein level of the R2R3-MYB transcription factor family showed GmMYB10 had a high degree of similarity with production of anthocyanin pigment1 in Arabidopsis and as well as sequences from other plant species related to the elevation of anthocyanin pigmentation. In transient transactivation assays, GmMYB10, co-expressed with AtbHLH2, strongly activated the GmDFR and AtDFR promoters. Transcripts of GmMYB10 and GmUFGT were highly abundant with onset of pigmentation and subsequently during red colouration. Our results suggest that GmMYB10 plays an important role in regulating anthocyanin biosynthesis both on the tree and after harvest, while GmUFGT may be a key biosynthetic gene in mangosteen pigmentation. The expression patterns of GmMYB10 and GmUFGT correlated with ethylene production that increased linearly until stage 5 (dark purple) and decreased thereafter. 1-Methycyclopropene (1-MCP) clearly delayed red colouration with resulting down-regulation of GmMYB10. These results suggest that the effect of ethylene on anthocyanin biosynthesis may be via the regulation of GmMYB10 expression.

  16. Characterization of two tartary buckwheat R2R3-MYB transcription factors and their regulation of proanthocyanidin biosynthesis.

    PubMed

    Bai, Yue-Chen; Li, Cheng-Lei; Zhang, Jin-Wen; Li, Shuang-Jiang; Luo, Xiao-Peng; Yao, Hui-Peng; Chen, Hui; Zhao, Hai-Xia; Park, Sang-Un; Wu, Qi

    2014-11-01

    Tartary buckwheat (Fagopyrum tataricum Gaertn.) contains high concentrations of flavonoids. The flavonoids are mainly represented by rutin, anthocyanins and proanthocyanins in tartary buckwheat. R2R3-type MYB transcription factors (TFs) play key roles in the transcriptional regulation of the flavonoid biosynthetic pathway. In this study, two TF genes, FtMYB1 and FtMYB2, were isolated from F. tataricum and characterized. The results of bioinformatic analysis indicated that the putative FtMYB1 and FtMYB2 proteins belonged to the R2R3-MYB family and displayed a high degree of similarity with TaMYB14 and AtMYB123/TT2. In vitro and in vivo evidence both showed the two proteins were located in the nucleus and exhibited transcriptional activation activities. During florescence, both FtMYB1 and FtMYB2 were more highly expressed in the flowers than any other organ. The overexpression of FtMYB1 and FtMYB2 significantly enhanced the accumulation of proanthocyanidins (PAs) and showed a strong effect on the target genes' expression in Nicotiana tabacum. The expression of dihydroflavonol-4-reductase (DFR) was upregulated to 5.6-fold higher than that of control, and the expression level was lower for flavonol synthase (FLS). To our knowledge, this is the first functional characterization of two MYB TFs from F. tataricum that control the PA pathway. PMID:24730512

  17. The MYB96 Transcription Factor Regulates Cuticular Wax Biosynthesis under Drought Conditions in Arabidopsis[W

    PubMed Central

    Seo, Pil Joon; Lee, Saet Buyl; Suh, Mi Chung; Park, Mi-Jeong; Go, Young Sam; Park, Chung-Mo

    2011-01-01

    Drought stress activates several defense responses in plants, such as stomatal closure, maintenance of root water uptake, and synthesis of osmoprotectants. Accumulating evidence suggests that deposition of cuticular waxes is also associated with plant responses to cellular dehydration. Yet, how cuticular wax biosynthesis is regulated in response to drought is unknown. We have recently reported that an Arabidopsis thaliana abscisic acid (ABA)–responsive R2R3-type MYB transcription factor, MYB96, promotes drought resistance. Here, we show that transcriptional activation of cuticular wax biosynthesis by MYB96 contributes to drought resistance. Microarray assays showed that a group of wax biosynthetic genes is upregulated in the activation-tagged myb96-1D mutant but downregulated in the MYB96-deficient myb96-1 mutant. Cuticular wax accumulation was altered accordingly in the mutants. In addition, activation of cuticular wax biosynthesis by drought and ABA requires MYB96. By contrast, biosynthesis of cutin monomers was only marginally affected in the mutants. Notably, the MYB96 protein acts as a transcriptional activator of genes encoding very-long-chain fatty acid–condensing enzymes involved in cuticular wax biosynthesis by directly binding to conserved sequence motifs present in the gene promoters. These results demonstrate that ABA-mediated MYB96 activation of cuticular wax biosynthesis serves as a drought resistance mechanism. PMID:21398568

  18. trans activation of gene expression by v-myb.

    PubMed Central

    Ibanez, C E; Lipsick, J S

    1990-01-01

    The v-myb oncogene causes acute myelomonocytic leukemia in chickens and transforms avian myeloid cells in vitro. Its product, p48v-myb, is a short-lived nuclear protein which binds DNA. We demonstrate that p48v-myb can function as a trans activator of gene expression in transient DNA transfection assays. trans activation requires the highly conserved amino-terminal DNA-binding domain and the less highly conserved carboxyl-terminal domain of p48v-myb, both of which are required for transformation. Multiple copies of a consensus sequence for DNA binding by p48v-myb inserted upstream of a herpes simplex virus thymidine kinase promoter are strongly stimulatory for transcriptional activation by a v-myb-VP16 fusion protein but not by p48v-myb itself, suggesting that the binding of p48v-myb to DNA may not be sufficient for trans activation. Images PMID:2325652

  19. Positive selection and functional divergence of R2R3-MYB paralogous genes expressed in inflorescence buds of Scutellaria species (Labiatae).

    PubMed

    Huang, Bing-Hong; Pang, Erli; Chen, Yi-Wen; Cao, Huifen; Ruan, Yu; Liao, Pei-Chun

    2015-03-13

    Anthocyanin is the main pigment forming floral diversity. Several transcription factors that regulate the expression of anthocyanin biosynthetic genes belong to the R2R3-MYB family. Here we examined the transcriptomes of inflorescence buds of Scutellaria species (skullcaps), identified the expression R2R3-MYBs, and detected the genetic signatures of positive selection for adaptive divergence across the rapidly evolving skullcaps. In the inflorescence buds, seven R2R3-MYBs were identified. MYB11 and MYB16 were detected to be positively selected. The signature of positive selection on MYB genes indicated that species diversification could be affected by transcriptional regulation, rather than at the translational level. When comparing among the background lineages of Arabidopsis, tomato, rice, and Amborella, heterogeneous evolutionary rates were detected among MYB paralogs, especially between MYB13 and MYB19. Significantly different evolutionary rates were also evidenced by type-I functional divergence between MYB13 and MYB19, and the accelerated evolutionary rates in MYB19, implied the acquisition of novel functions. Another paralogous pair, MYB2/7 and MYB11, revealed significant radical amino acid changes, indicating divergence in the regulation of different anthocyanin-biosynthetic enzymes. Our findings not only showed that Scutellaria R2R3-MYBs are functionally divergent and positively selected, but also indicated the adaptive relevance of regulatory genes in floral diversification.

  20. TaMYB13-1, a R2R3 MYB transcription factor, regulates the fructan synthetic pathway and contributes to enhanced fructan accumulation in bread wheat.

    PubMed

    Kooiker, Maarten; Drenth, Janneke; Glassop, Donna; McIntyre, C Lynne; Xue, Gang-Ping

    2013-09-01

    Fructans are the major component of temporary carbon reserve in the stem of temperate cereals, which is used for grain filling. Three families of fructosyltransferases are directly involved in fructan synthesis in the vacuole of Triticum aestivum. The regulatory network of the fructan synthetic pathway is largely unknown. Recently, a sucrose-upregulated wheat MYB transcription factor (TaMYB13-1) was shown to be capable of activating the promoter activities of sucrose:sucrose 1-fructosyltransferase (1-SST) and sucrose:fructan 6-fructosyltransferase (6-SFT) in transient transactivation assays. This work investigated TaMYB13-1 target genes and their influence on fructan synthesis in transgenic wheat. TaMYB13-1 overexpression resulted in upregulation of all three families of fructosyltransferases including fructan:fructan 1-fructosyltransferase (1-FFT). A γ-vacuolar processing enzyme (γ-VPE1), potentially involved in processing the maturation of fructosyltransferases in the vacuole, was also upregulated by TaMYB13-1 overexpression. Multiple TaMYB13 DNA-binding motifs were identified in the Ta1-FFT1 and Taγ-VPE1 promoters and were bound strongly by TaMYB13-1. The expression profiles of these target genes and TaMYB13-1 were highly correlated in recombinant inbred lines and during stem development as well as the transgenic and non-transgenic wheat dataset, further supporting a direct regulation of these genes by TaMYB13-1. TaMYB13-1 overexpression in wheat led to enhanced fructan accumulation in the leaves and stems and also increased spike weight and grain weight per spike in transgenic plants under water-limited conditions. These data suggest that TaMYB13-1 plays an important role in coordinated upregulation of genes necessary for fructan synthesis and can be used as a molecular tool to improve the high fructan trait.

  1. TaMYB13-1, a R2R3 MYB transcription factor, regulates the fructan synthetic pathway and contributes to enhanced fructan accumulation in bread wheat

    PubMed Central

    Kooiker, Maarten; Drenth, Janneke; Glassop, Donna; McIntyre, C. Lynne; Xue, Gang-Ping

    2013-01-01

    Fructans are the major component of temporary carbon reserve in the stem of temperate cereals, which is used for grain filling. Three families of fructosyltransferases are directly involved in fructan synthesis in the vacuole of Triticum aestivum. The regulatory network of the fructan synthetic pathway is largely unknown. Recently, a sucrose-upregulated wheat MYB transcription factor (TaMYB13-1) was shown to be capable of activating the promoter activities of sucrose:sucrose 1-fructosyltransferase (1-SST) and sucrose:fructan 6-fructosyltransferase (6-SFT) in transient transactivation assays. This work investigated TaMYB13-1 target genes and their influence on fructan synthesis in transgenic wheat. TaMYB13-1 overexpression resulted in upregulation of all three families of fructosyltransferases including fructan:fructan 1-fructosyltransferase (1-FFT). A γ-vacuolar processing enzyme (γ-VPE1), potentially involved in processing the maturation of fructosyltransferases in the vacuole, was also upregulated by TaMYB13-1 overexpression. Multiple TaMYB13 DNA-binding motifs were identified in the Ta1-FFT1 and Taγ-VPE1 promoters and were bound strongly by TaMYB13-1. The expression profiles of these target genes and TaMYB13-1 were highly correlated in recombinant inbred lines and during stem development as well as the transgenic and non-transgenic wheat dataset, further supporting a direct regulation of these genes by TaMYB13-1. TaMYB13-1 overexpression in wheat led to enhanced fructan accumulation in the leaves and stems and also increased spike weight and grain weight per spike in transgenic plants under water-limited conditions. These data suggest that TaMYB13-1 plays an important role in coordinated upregulation of genes necessary for fructan synthesis and can be used as a molecular tool to improve the high fructan trait. PMID:23873993

  2. Spatially and temporally restricted expression of PtrMYB021 regulates secondary cell wall formation in Arabidopsis

    DOE PAGESBeta

    Wang, Wei; Li, Eryang; Porth, Ilga; Chen, Jin-Gui; Mansfield, Shawn D.; Douglas, Carl J.; Wang, Shucai

    2016-02-02

    Among the R2R3 MYB transcription factors that involve in the regulation of secondary cell wall formation in Arabidopsis, MYB46 alone is sufficient to induce the entire secondary cell wall biosynthesis program. PtrMYB021, the poplar homolog of MYB46, has been reported to regulate secondary cell wall formation when expressed in Arabidopsis. We report here that spatially and temporally restricted expression of PtrMYB021 is critical for its function in regulating secondary cell wall formation. By using quantitative RT-PCR, we found that PtrMYB021 was expressed primarily in xylem tissues. When expressed in Arabidopsis under the control of PtrCesA8, but not the 35S promoter,more » PtrMYB021 increased secondary cell wall thickness, which is likely caused by increased lignification as well as changes in cell wall carbohydrate composition. Consistent with this, elevated expression of lignin and cellulose biosynthetic genes were observed in the transgenic plants. Finally, when expressed in Arabidopsis protoplasts as fusion proteins to the Gal4 DNA binding domain, PtrMYB021 activated the reporter gene Gal4-GUS. In summary, our results suggest that PtrMYB021 is a transcriptional activator, and spatially and temporally restricted expression of PtrMYB021 in Arabidopsis regulates secondary cell wall formation by activating a subset of secondary cell wall biosynthesis genes.« less

  3. Regulation of Cell Proliferation in the Stomatal Lineage by the Arabidopsis MYB FOUR LIPS via Direct Targeting of Core Cell Cycle Genes[W

    PubMed Central

    Xie, Zidian; Lee, EunKyoung; Lucas, Jessica R.; Morohashi, Kengo; Li, Dongmei; Murray, James A.H.; Sack, Fred D.; Grotewold, Erich

    2010-01-01

    Stomata, which are epidermal pores surrounded by two guard cells, develop from a specialized stem cell lineage and function in shoot gas exchange. The Arabidopsis thaliana FOUR LIPS (FLP) and MYB88 genes encode closely related and atypical two-MYB-repeat proteins, which when mutated result in excess divisions and abnormal groups of stomata in contact. Consistent with a role in transcription, we show here that FLP and MYB88 are nuclear proteins with DNA binding preferences distinct from other known MYBs. To identify possible FLP/MYB88 transcriptional targets, we used chromatin immunoprecitation (ChIP) followed by hybridization to Arabidopsis whole genome tiling arrays. These ChIP-chip data indicate that FLP/MYB88 target the upstream regions especially of cell cycle genes, including cyclins, cyclin-dependent kinases (CDKs), and components of the prereplication complex. In particular, we show that FLP represses the expression of the mitosis-inducing factor CDKB1;1, which, along with CDKB1;2, is specifically required both for the last division in the stomatal pathway and for cell overproliferation in flp mutants. We propose that FLP and MYB88 together integrate patterning with the control of cell cycle progression and terminal differentiation through multiple and direct cell cycle targets. FLP recognizes a distinct cis-regulatory element that overlaps with that of the cell cycle activator E2F-DP in the CDKB1;1 promoter, suggesting that these MYBs may also modulate E2F-DP pathways. PMID:20675570

  4. Three R2R3-MYB Transcription Factors Regulate Distinct Floral Pigmentation Patterning in Phalaenopsis spp.1[OPEN

    PubMed Central

    Hsu, Chia-Chi; Chen, You-Yi; Tsai, Wen-Chieh; Chen, Wen-Huei; Chen, Hong-Hwa

    2015-01-01

    Orchidaceae are well known for their fascinating floral morphologic features, specialized pollination, and distinctive ecological strategies. With their long-lasting flowers of various colors and pigmentation patterning, Phalaenopsis spp. have become important ornamental plants worldwide. In this study, we identified three R2R3-MYB transcription factors PeMYB2, PeMYB11, and PeMYB12. Their expression profiles were concomitant with red color formation in Phalaenopsis spp. flowers. Transient assay of overexpression of three PeMYBs verified that PeMYB2 resulted in anthocyanin accumulation, and these PeMYBs could activate the expression of three downstream structural genes Phalaenopsis spp. Flavanone 3-hydroxylase5, Phalaenopsis spp. Dihydroflavonol 4-reductase1, and Phalaenopsis spp. Anthocyanidin synthase3. In addition, these three PeMYBs participated in the distinct pigmentation patterning in a single flower, which was revealed by virus-induced gene silencing. In the sepals/petals, silencing of PeMYB2, PeMYB11, and PeMYB12 resulted in the loss of the full-red pigmentation, red spots, and venation patterns, respectively. Moreover, different pigmentation patterning was regulated by PeMYBs in the sepals/petals and lip. PeMYB11 was responsive to the red spots in the callus of the lip, and PeMYB12 participated in the full pigmentation in the central lobe of the lip. The differential pigmentation patterning was validated by RNA in situ hybridization. Additional assessment was performed in six Phalaenopsis spp. cultivars with different color patterns. The combined expression of these three PeMYBs in different ratios leads to a wealth of complicated floral pigmentation patterning in Phalaenopsis spp. PMID:25739699

  5. Molecular characterization of Quercus suber MYB1, a transcription factor up-regulated in cork tissues.

    PubMed

    Almeida, Tânia; Menéndez, Esther; Capote, Tiago; Ribeiro, Teresa; Santos, Conceição; Gonçalves, Sónia

    2013-01-15

    The molecular processes associated with cork development in Quercus suber L. are poorly understood. A previous molecular approach identified a list of genes potentially important for cork formation and differentiation, providing a new basis for further molecular studies. This report is the first molecular characterization of one of these candidate genes, QsMYB1, coding for an R2R3-MYB transcription factor. The R2R3-MYB gene sub-family has been described as being involved in the phenylpropanoid and lignin pathways, both involved in cork biosynthesis. The results showed that the expression of QsMYB1 is putatively mediated by an alternative splicing (AS) mechanism that originates two different transcripts (QsMYB1.1 and QsMYB1.2), differing only in the 5'-untranslated region, due to retention of the first intron in one of the variants. Moreover, within the retained intron, a simple sequence repeat (SSR) was identified. The upstream regulatory region of QsMYB1 was extended by a genome walking approach, which allowed the identification of the putative gene promoter region. The relative expression pattern of QsMYB1 transcripts determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) revealed that both transcripts were up-regulated in cork tissues; the detected expression was several times higher in newly formed cork harvested from trees producing virgin, second or reproduction cork when compared with wood. Moreover, the expression analysis of QsMYB1 in several Q. suber organs showed very low expression in young branches and roots, whereas in leaves, immature acorns or male flowers, no expression was detected. These preliminary results suggest that QsMYB1 may be related to secondary growth and, in particular, with the cork biosynthesis process with a possible alternative splicing mechanism associated with its regulatory function.

  6. McMYB10 regulates coloration via activating McF3'H and later structural genes in ever-red leaf crabapple.

    PubMed

    Tian, Ji; Peng, Zhen; Zhang, Jie; Song, Tingting; Wan, Huihua; Zhang, Meiling; Yao, Yuncong

    2015-09-01

    The ever-red leaf trait, which is important for breeding ornamental and higher anthocyanin plants, rarely appears in Malus families, but little is known about the regulation of anthocyanin biosynthesis involved in the red leaves. In our study, HPLC analysis showed that the anthocyanin concentration in ever-red leaves, especially cyanidin, was significantly higher than that in evergreen leaves. The transcript level of McMYB10 was significantly correlated with anthocyanin synthesis between the 'Royalty' and evergreen leaf 'Flame' cultivars during leaf development. We also found the ever-red leaf colour cultivar 'Royalty' contained the known R6 : McMYB10 sequence, but was not in the evergreen leaf colour cultivar 'Flame', which have been reported in apple fruit. The distinction in promoter region maybe is the main reason why higher expression level of McMYB10 in red foliage crabapple cultivar. Furthermore, McMYB10 promoted anthocyanin biosynthesis in crabapple leaves and callus at low temperatures and during long-day treatments. Both heterologous expression in tobacco (Nicotiana tabacum) and Arabidopsis pap1 mutant, and homologous expression in crabapple and apple suggested that McMYB10 could promote anthocyanins synthesis and enhanced anthocyanin accumulation in plants. Interestingly, electrophoretic mobility shift assays, coupled with yeast one-hybrid analysis, revealed that McMYB10 positively regulates McF3'H via directly binding to AACCTAAC and TATCCAACC motifs in the promoter. To sum up, our results demonstrated that McMYB10 plays an important role in ever-red leaf coloration, by positively regulating McF3'H in crabapple. Therefore, our work provides new perspectives for ornamental fruit tree breeding.

  7. An R2R3 MYB transcription factor associated with regulation of the anthocyanin biosynthetic pathway in Rosaceae

    PubMed Central

    2010-01-01

    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. PMID:20302676

  8. The Scutellaria baicalensis R2R3-MYB transcription factors modulates flavonoid biosynthesis by regulating GA metabolism in transgenic tobacco plants.

    PubMed

    Yuan, Yuan; Wu, Chong; Liu, Yunjun; Yang, Jian; Huang, Luqi

    2013-01-01

    R2R3-MYB proteins play role in plant development, response to biotic and abiotic stress, and regulation of primary and secondary metabolism. Little is known about the R2R3-MYB proteins in Scutellaria baicalensis which is an important Chinese medical plant. In this paper, nineteen putative SbMYB genes were identified from a S. baicalensis cDNA library, and eleven R2R3-MYBs were clustered into 5 subgroups according to phylogenetic reconstruction. In the S. baicalensis leaves which were sprayed with GA3, SbMYB2 and SbMYB7 had similar expression pattern with SbPALs, indicating that SbMYB2 and SbMYB7 might be involved in the flavonoid metabolism. Transactivation assay results showed that SbMYB2 and SbMYB7 can function as transcriptional activator. The expression of several flavonoid biosynthesis-related genes were induced or suppressed by overexpression of SbMYB2 or SbMYB7 in transgenic tobacco plants. Consistent with the change of the expression of NtDH29 and NtCHI, the contents of dicaffeoylspermidine and quercetin-3,7-O-diglucoside in SbMYB2-overexpressing or SbMYB7-overexpressing transgenic tobacco plants were decreased. The transcriptional level of NtUFGT in transgenic tobacco overexpressing SbMYB7 and the transcriptional level of NtHCT in SbMYB2-overexpressing tobacco plants were increased; however the application of GA3 inhibited the transcriptional level of these two genes. These results suggest that SbMYB2 and SbMYB7 might regulate the flavonoid biosynthesis through GA metabolism.

  9. The Scutellaria baicalensis R2R3-MYB Transcription Factors Modulates Flavonoid Biosynthesis by Regulating GA Metabolism in Transgenic Tobacco Plants

    PubMed Central

    Liu, Yunjun; Yang, Jian; Huang, Luqi

    2013-01-01

    R2R3-MYB proteins play role in plant development, response to biotic and abiotic stress, and regulation of primary and secondary metabolism. Little is known about the R2R3-MYB proteins in Scutellaria baicalensis which is an important Chinese medical plant. In this paper, nineteen putative SbMYB genes were identified from a S. baicalensis cDNA library, and eleven R2R3-MYBs were clustered into 5 subgroups according to phylogenetic reconstruction. In the S. baicalensis leaves which were sprayed with GA3, SbMYB2 and SbMYB7 had similar expression pattern with SbPALs, indicating that SbMYB2 and SbMYB7 might be involved in the flavonoid metabolism. Transactivation assay results showed that SbMYB2 and SbMYB7 can function as transcriptional activator. The expression of several flavonoid biosynthesis-related genes were induced or suppressed by overexpression of SbMYB2 or SbMYB7 in transgenic tobacco plants. Consistent with the change of the expression of NtDH29 and NtCHI, the contents of dicaffeoylspermidine and quercetin-3,7-O-diglucoside in SbMYB2-overexpressing or SbMYB7-overexpressing transgenic tobacco plants were decreased. The transcriptional level of NtUFGT in transgenic tobacco overexpressing SbMYB7 and the transcriptional level of NtHCT in SbMYB2-overexpressing tobacco plants were increased; however the application of GA3 inhibited the transcriptional level of these two genes. These results suggest that SbMYB2 and SbMYB7 might regulate the flavonoid biosynthesis through GA metabolism. PMID:24143216

  10. Molecular cloning and expression profile of an abiotic stress and hormone responsive MYB transcription factor gene from Panax ginseng.

    PubMed

    Afrin, Sadia; Zhu, Jie; Cao, Hongzhe; Huang, Jingjia; Xiu, Hao; Luo, Tiao; Luo, Zhiyong

    2015-04-01

    The v-myb avian myeloblastosis viral oncogene homolog (MYB) family constitutes one of the most abundant groups of transcription factors and plays vital roles in developmental processes and defense responses in plants. A ginseng (Panax ginseng C.A. Meyer) MYB gene was cloned and designated as PgMYB1. The cDNA of PgMYB1 is 762 base pairs long and encodes the R2R3-type protein consisting 238 amino acids. Subcellular localization showed that PgMYB1-mGFP5 fusion protein was specifically localized in the nucleus. To understand the functional roles of PgMYB1, we investigated the expression patterns of PgMYB1 in different tissues and under various conditions. Quantitative real-time polymerase chain reaction and western blot analysis showed that PgMYB1 was expressed at higher level in roots, leaves, and lateral roots than in stems and seeds. The expression of PgMYB1 was up-regulated by abscisic acid, salicylic acid, NaCl, and cold (chilling), and down-regulated by methyl jasmonate. These results suggest that PgMYB1 might be involved in responding to environmental stresses and hormones. PMID:25791525

  11. Molecular cloning and expression profile of an abiotic stress and hormone responsive MYB transcription factor gene from Panax ginseng.

    PubMed

    Afrin, Sadia; Zhu, Jie; Cao, Hongzhe; Huang, Jingjia; Xiu, Hao; Luo, Tiao; Luo, Zhiyong

    2015-04-01

    The v-myb avian myeloblastosis viral oncogene homolog (MYB) family constitutes one of the most abundant groups of transcription factors and plays vital roles in developmental processes and defense responses in plants. A ginseng (Panax ginseng C.A. Meyer) MYB gene was cloned and designated as PgMYB1. The cDNA of PgMYB1 is 762 base pairs long and encodes the R2R3-type protein consisting 238 amino acids. Subcellular localization showed that PgMYB1-mGFP5 fusion protein was specifically localized in the nucleus. To understand the functional roles of PgMYB1, we investigated the expression patterns of PgMYB1 in different tissues and under various conditions. Quantitative real-time polymerase chain reaction and western blot analysis showed that PgMYB1 was expressed at higher level in roots, leaves, and lateral roots than in stems and seeds. The expression of PgMYB1 was up-regulated by abscisic acid, salicylic acid, NaCl, and cold (chilling), and down-regulated by methyl jasmonate. These results suggest that PgMYB1 might be involved in responding to environmental stresses and hormones.

  12. A subgroup of MYB transcription factor genes undergoes highly conserved alternative splicing in Arabidopsis and rice.

    PubMed

    Li, Jigang; Li, Xiaojuan; Guo, Lei; Lu, Feng; Feng, Xiaojie; He, Kun; Wei, Liping; Chen, Zhangliang; Qu, Li-Jia; Gu, Hongya

    2006-01-01

    MYB transcription factor genes play important roles in many developmental processes and in various defence responses of plants. Two Arabidopsis R2R3-type MYB genes, AtMYB59 and AtMYB48, were found to undergo similar alternative splicing. Both genes have four distinctively spliced transcripts that encode either MYB-related proteins or R2R3-MYB proteins. An extensive BLAST search of the GenBank database resulted in finding and cloning two rice homologues, both of which were also found to share a similar alternative splicing pattern. In a semi-quantitative study, the expression of one splice variant of AtMYB59 was found to be differentially regulated in treatments with different phytohormones and stresses. GFP fusion protein analysis revealed that both of the two predicted nuclear localization signals (NLSs) in the R3 domain are required for localizing to the nucleus. Promoter-GUS analysis in transgenic plants showed that 5'-UTR is sufficient for the translation initiation of type 3 transcripts (encoding R2R3-MYB proteins), but not for type 2 transcripts (encoding MYB-related proteins). Moreover, a new type of non-canonical intron, with the same nucleotide repeats at the 5' and 3' splice sites, was identified. Thirty-eight Arabidopsis and rice genes were found to have this type of non-canonical intron, most of which undergo alternative splicing. These data suggest that this subgroup of transcription factor genes may be involved in multiple biological processes and may be transcriptionally regulated by alternative splicing. PMID:16531467

  13. Regulation of root hair cell differentiation by R3 MYB transcription factors in tomato and Arabidopsis

    PubMed Central

    Tominaga-Wada, Rumi; Wada, Takuji

    2014-01-01

    CAPRICE (CPC) encodes a small protein with an R3 MYB motif and regulates root hair and trichome cell differentiation in Arabidopsis thaliana. Six additional CPC-like MYB proteins including TRIPTYCHON (TRY), ENHANCER OF TRY AND CPC1 (ETC1), ENHANCER OF TRY AND CPC2 (ETC2), ENHANCER OF TRY AND CPC3/CPC-LIKE MYB3 (ETC3/CPL3), TRICHOMELESS1 (TCL1), and TRICHOMELESS2/CPC-LIKE MYB4 (TCL2/CPL4) also have the ability to regulate root hair and/or trichome cell differentiation in Arabidopsis. In this review, we describe our latest findings on how CPC-like MYB transcription factors regulate root hair cell differentiation. Recently, we identified the tomato SlTRY gene as an ortholog of the Arabidopsis TRY gene. Transgenic Arabidopsis plants harboring SlTRY produced more root hairs, a phenotype similar to that of 35S::CPC transgenic plants. CPC is also known to be involved in anthocyanin biosynthesis. Anthocyanin accumulation was repressed in the SlTRY transgenic plants, suggesting that SlTRY can also influence anthocyanin biosynthesis. We concluded that tomato and Arabidopsis partially use similar transcription factors for root hair cell differentiation, and that a CPC-like R3 MYB may be a key common regulator of plant root-hair development. PMID:24659995

  14. MYB36 regulates the transition from proliferation to differentiation in the Arabidopsis root

    PubMed Central

    Liberman, Louisa M.; Sparks, Erin E.; Moreno-Risueno, Miguel A.; Petricka, Jalean J.; Benfey, Philip N.

    2015-01-01

    Stem cells are defined by their ability to self-renew and produce daughter cells that proliferate and mature. These maturing cells transition from a proliferative state to a terminal state through the process of differentiation. In the Arabidopsis thaliana root the transcription factors SCARECROW and SHORTROOT regulate specification of the bipotent stem cell that gives rise to cortical and endodermal progenitors. Subsequent progenitor proliferation and differentiation generate mature endodermis, marked by the Casparian strip, a cell-wall modification that prevents ion diffusion into and out of the vasculature. We identified a transcription factor, MYB DOMAIN PROTEIN 36 (MYB36), that regulates the transition from proliferation to differentiation in the endodermis. We show that SCARECROW directly activates MYB36 expression, and that MYB36 likely acts in a feed-forward loop to regulate essential Casparian strip formation genes. We show that myb36 mutants have delayed and defective barrier formation as well as extra divisions in the meristem. Our results demonstrate that MYB36 is a critical positive regulator of differentiation and negative regulator of cell proliferation. PMID:26371322

  15. Regulation of ecmF gene expression and genetic hierarchy among STATa, CudA, and MybC on several prestalk A-specific gene expressions in Dictyostelium.

    PubMed

    Saga, Yukika; Inamura, Tomoka; Shimada, Nao; Kawata, Takefumi

    2016-05-01

    STATa, a Dictyostelium homologue of metazoan signal transducer and activator of transcription, is important for the organizer function in the tip region of the migrating Dictyostelium slug. We previously showed that ecmF gene expression depends on STATa in prestalk A (pstA) cells, where STATa is activated. Deletion and site-directed mutagenesis analysis of the ecmF/lacZ fusion gene in wild-type and STATa null strains identified an imperfect inverted repeat sequence, ACAAATANTATTTGT, as a STATa-responsive element. An upstream sequence element was required for efficient expression in the rear region of pstA zone; an element downstream of the inverted repeat was necessary for sufficient prestalk expression during culmination. Band shift analyses using purified STATa protein detected no sequence-specific binding to those ecmF elements. The only verified upregulated target gene of STATa is cudA gene; CudA directly activates expL7 gene expression in prestalk cells. However, ecmF gene expression was almost unaffected in a cudA null mutant. Several previously reported putative STATa target genes were also expressed in cudA null mutant but were downregulated in STATa null mutant. Moreover, mybC, which encodes another transcription factor, belonged to this category, and ecmF expression was downregulated in a mybC null mutant. These findings demonstrate the existence of a genetic hierarchy for pstA-specific genes, which can be classified into two distinct STATa downstream pathways, CudA dependent and independent. The ecmF expression is indirectly upregulated by STATa in a CudA-independent activation manner but dependent on MybC, whose expression is positively regulated by STATa.

  16. R2R3-type MYB transcription factor, CmMYB1, is a central nitrogen assimilation regulator in Cyanidioschyzon merolae

    PubMed Central

    Imamura, Sousuke; Kanesaki, Yu; Ohnuma, Mio; Inouye, Takayuki; Sekine, Yasuhiko; Fujiwara, Takayuki; Kuroiwa, Tsuneyoshi; Tanaka, Kan

    2009-01-01

    Plant cells sense environmental nitrogen levels and alter their gene expression accordingly to survive; however, the underlying regulatory mechanisms still remains to be elucidated. Here, we identified and characterized a transcription factor that is responsible for expression of nitrogen assimilation genes in a unicellular red alga Cyanidioschyzon merolae. DNA microarray and Northern blot analyses revealed that transcript of the gene encoding CmMYB1, an R2R3-type MYB transcription factor, increased 1 h after nitrogen depletion. The CmMYB1 protein started to accumulate after 2 h and reached a peak after 4 h after nitrogen depletion, correlating with the expression of key nitrogen assimilation genes, such as CmNRT, CmNAR, CmNIR, CmAMT, and CmGS. Although the transcripts of these nitrogen assimilation genes were detected in nitrate-grown cells, they disappeared upon the addition of preferred nitrogen source such as ammonium or glutamine, suggesting the presence of a nitrogen catabolite repression (NCR) mechanism. The nitrogen depletion-induced gene expression disappeared in a CmMYB1-null mutant, and the mutant showed decreased cell viability after exposure to the nitrogen-depleted conditions compared with the parental strain. Chromatin immunoprecipitation analysis demonstrated that CmMYB1 specifically occupied these nitrogen-responsive promoter regions only under nitrogen-depleted conditions, and electrophoretic mobility shift assays using crude cell extract revealed specific binding of CmMYB1, or a complex containing CmMYB1, to these promoters. Thus, the presented results indicated that CmMYB1 is a central nitrogen regulator in C. merolae. PMID:19592510

  17. R2R3-type MYB transcription factor, CmMYB1, is a central nitrogen assimilation regulator in Cyanidioschyzon merolae.

    PubMed

    Imamura, Sousuke; Kanesaki, Yu; Ohnuma, Mio; Inouye, Takayuki; Sekine, Yasuhiko; Fujiwara, Takayuki; Kuroiwa, Tsuneyoshi; Tanaka, Kan

    2009-07-28

    Plant cells sense environmental nitrogen levels and alter their gene expression accordingly to survive; however, the underlying regulatory mechanisms still remains to be elucidated. Here, we identified and characterized a transcription factor that is responsible for expression of nitrogen assimilation genes in a unicellular red alga Cyanidioschyzon merolae. DNA microarray and Northern blot analyses revealed that transcript of the gene encoding CmMYB1, an R2R3-type MYB transcription factor, increased 1 h after nitrogen depletion. The CmMYB1 protein started to accumulate after 2 h and reached a peak after 4 h after nitrogen depletion, correlating with the expression of key nitrogen assimilation genes, such as CmNRT, CmNAR, CmNIR, CmAMT, and CmGS. Although the transcripts of these nitrogen assimilation genes were detected in nitrate-grown cells, they disappeared upon the addition of preferred nitrogen source such as ammonium or glutamine, suggesting the presence of a nitrogen catabolite repression (NCR) mechanism. The nitrogen depletion-induced gene expression disappeared in a CmMYB1-null mutant, and the mutant showed decreased cell viability after exposure to the nitrogen-depleted conditions compared with the parental strain. Chromatin immunoprecipitation analysis demonstrated that CmMYB1 specifically occupied these nitrogen-responsive promoter regions only under nitrogen-depleted conditions, and electrophoretic mobility shift assays using crude cell extract revealed specific binding of CmMYB1, or a complex containing CmMYB1, to these promoters. Thus, the presented results indicated that CmMYB1 is a central nitrogen regulator in C. merolae. PMID:19592510

  18. Distal regulation of c-myb expression during IL-6-induced differentiation in murine myeloid progenitor M1 cells.

    PubMed

    Zhang, Junfang; Han, Bingshe; Li, Xiaoxia; Bies, Juraj; Jiang, Penglei; Koller, Richard P; Wolff, Linda

    2016-01-01

    The c-Myb transcription factor is a major regulator that controls differentiation and proliferation of hematopoietic progenitor cells, which is frequently deregulated in hematological diseases, such as lymphoma and leukemia. Understanding of the mechanisms regulating the transcription of c-myb gene is challenging as it lacks a typical promoter and multiple factors are involved. Our previous studies identified some distal regulatory elements in the upstream regions of c-myb gene in murine myeloid progenitor M1 cells, but the detailed mechanisms still remain unclear. In the present study, we found that a cell differentiation-related DNase1 hypersensitive site is located at a -28k region upstream of c-myb gene and that transcription factors Hoxa9, Meis1 and PU.1 bind to the -28k region. Circular chromosome conformation capture (4C) assay confirmed the interaction between the -28k region and the c-myb promoter, which is supported by the enrichment of CTCF and Cohesin. Our analysis also points to a critical role for Hoxa9 and PU.1 in distal regulation of c-myb expression in murine myeloid cells and cell differentiation. Overexpression of Hoxa9 disrupted the IL-6-induced differentiation of M1 cells and upregulated c-myb expression through binding of the -28k region. Taken together, our results provide an evidence for critical role of the -28k region in distal regulatory mechanism for c-myb gene expression during differentiation of myeloid progenitor M1 cells. PMID:27607579

  19. Ectopic expression of MYB46 identifies transcriptional regulatory genes involved in secondary wall biosynthesis in Arabidopsis.

    PubMed

    Ko, Jae-Heung; Kim, Won-Chan; Han, Kyung-Hwan

    2009-11-01

    MYB46 functions as a transcriptional switch that turns on the genes necessary for secondary wall biosynthesis. Elucidating the transcriptional regulatory network immediately downstream of MYB46 is crucial to our understanding of the molecular and biochemical processes involved in the biosynthesis and deposition of secondary walls in plants. To gain insights into MYB46-mediated transcriptional regulation, we first established an inducible secondary wall thickening system in Arabidopsis by expressing MYB46 under the control of dexamethasone-inducible promoter. Then, we used an ATH1 GeneChip microarray and Illumina digital gene expression system to obtain a series of transcriptome profiles with regard to the induction of secondary wall development. These analyses allowed us to identify a group of transcription factors whose expression coincided with or preceded the induction of secondary wall biosynthetic genes. A transient transcriptional activation assay was used to confirm the hierarchical relationships among the transcription factors in the network. The in vivo assay showed that MYB46 transcriptionally activates downstream target transcription factors, three of which (AtC3H14, MYB52 and MYB63) were shown to be able to activate secondary wall biosynthesis genes. AtC3H14 activated the transcription of all of the secondary wall biosynthesis genes tested, suggesting that AtC3H14 may be another master regulator of secondary wall biosynthesis. The transcription factors identified here may include direct activators of secondary wall biosynthesis genes. The present study discovered novel hierarchical relationships among the transcription factors involved in the transcriptional regulation of secondary wall biosynthesis, and generated several testable hypotheses.

  20. The Arabidopsis MIEL1 E3 ligase negatively regulates ABA signalling by promoting protein turnover of MYB96.

    PubMed

    Lee, Hong Gil; Seo, Pil Joon

    2016-01-01

    The phytohormone abscisic acid (ABA) regulates plant responses to various environmental challenges. Controlled protein turnover is an important component of ABA signalling. Here we show that the RING-type E3 ligase MYB30-INTERACTING E3 LIGASE 1 (MIEL1) regulates ABA sensitivity by promoting MYB96 turnover in Arabidopsis. Germination of MIEL1-deficient mutant seeds is hypersensitive to ABA, whereas MIEL1-overexpressing transgenic seeds are less sensitive. MIEL1 can interact with MYB96, a regulator of ABA signalling, and stimulate its ubiquitination and degradation. Genetic analysis shows that MYB96 is epistatic to MIEL1 in the control of ABA sensitivity in seeds. While MIEL1 acts primarily via MYB96 in seed germination, MIEL1 regulates protein turnover of both MYB96 and MYB30 in vegetative tissues. We find that ABA regulates the expression of MYB30-responsive genes during pathogen infection and this regulation is partly dependent on MIEL1. These results suggest that MIEL1 may facilitate crosstalk between ABA and biotic stress signalling. PMID:27615387

  1. The Arabidopsis MIEL1 E3 ligase negatively regulates ABA signalling by promoting protein turnover of MYB96

    PubMed Central

    Lee, Hong Gil; Seo, Pil Joon

    2016-01-01

    The phytohormone abscisic acid (ABA) regulates plant responses to various environmental challenges. Controlled protein turnover is an important component of ABA signalling. Here we show that the RING-type E3 ligase MYB30-INTERACTING E3 LIGASE 1 (MIEL1) regulates ABA sensitivity by promoting MYB96 turnover in Arabidopsis. Germination of MIEL1-deficient mutant seeds is hypersensitive to ABA, whereas MIEL1-overexpressing transgenic seeds are less sensitive. MIEL1 can interact with MYB96, a regulator of ABA signalling, and stimulate its ubiquitination and degradation. Genetic analysis shows that MYB96 is epistatic to MIEL1 in the control of ABA sensitivity in seeds. While MIEL1 acts primarily via MYB96 in seed germination, MIEL1 regulates protein turnover of both MYB96 and MYB30 in vegetative tissues. We find that ABA regulates the expression of MYB30-responsive genes during pathogen infection and this regulation is partly dependent on MIEL1. These results suggest that MIEL1 may facilitate crosstalk between ABA and biotic stress signalling. PMID:27615387

  2. Transgene Insertion in Proximity to thec-myb Gene Disrupts Erythroid-Megakaryocytic Lineage Bifurcation▿

    PubMed Central

    Mukai, Harumi Y.; Motohashi, Hozumi; Ohneda, Osamu; Suzuki, Norio; Nagano, Masumi; Yamamoto, Masayuki

    2006-01-01

    The nuclear proto-oncogene c-myb plays crucial roles in the growth, survival, and differentiation of hematopoietic cells. We established three lines of erythropoietin receptor-transgenic mice and found that one of them exhibited anemia, thrombocythemia, and splenomegaly. These abnormalities were independent of the function of the transgenic erythropoietin receptor and were observed exclusively in mice harboring the transgene homozygously, suggesting transgenic disruption of a certain gene. The transgene was inserted 77 kb upstream of the c-myb gene, and c-Myb expression was markedly decreased in megakaryocyte/erythrocyte lineage-restricted progenitors (MEPs) of the homozygous mutant mice. In the bone marrows and spleens of the mutant mice, numbers of megakaryocytes were increased and numbers of erythroid progenitors were decreased. These abnormalities were reproducible in vitro in a coculture assay of MEPs with OP9 cells but eliminated by the retroviral expression of c-Myb in MEPs. The erythroid/megakaryocytic abnormalities were reconstituted in mice in vivo by transplantation of mutant mouse bone marrow cells. These results demonstrate that the transgene insertion into the c-myb gene far upstream regulatory region affects the gene expression at the stage of MEPs, leading to an imbalance between erythroid and megakaryocytic cells, and suggest that c-Myb is an essential regulator of the erythroid-megakaryocytic lineage bifurcation. PMID:16940183

  3. MYB-related transcription factors function as regulators of the circadian clock and anthocyanin biosynthesis in Arabidopsis

    PubMed Central

    Nguyen, Nguyen Hoai; Lee, Hojoung

    2016-01-01

    ABSTRACT In Arabidopsis, the MYB (myeloblastosis) gene family contains more than 190 members, which play a number of roles in plant growth and development. Based on their protein structure, this gene family was divided into several subclasses, including the MYB-related class. Currently, an MYB-related gene designated as MYB-like Domain (AtMYBD) has been shown to function as a positive regulator of anthocyanin biosynthesis in Arabidopsis. This gene was found to belong to the CCA1-like (circadian clock-associated 1) group, which represents several genes that are master regulators of the circadian clocks of plants. Here, we speculate that AtMYBD is able to regulate anthocyanin biosynthesis in Arabidopsis thaliana in a circadian clock-related manner. PMID:26905954

  4. Transcriptional Regulatory Network Analysis of MYB Transcription Factor Family Genes in Rice

    PubMed Central

    Smita, Shuchi; Katiyar, Amit; Chinnusamy, Viswanathan; Pandey, Dev M.; Bansal, Kailash C.

    2015-01-01

    MYB transcription factor (TF) is one of the largest TF families and regulates defense responses to various stresses, hormone signaling as well as many metabolic and developmental processes in plants. Understanding these regulatory hierarchies of gene expression networks in response to developmental and environmental cues is a major challenge due to the complex interactions between the genetic elements. Correlation analyses are useful to unravel co-regulated gene pairs governing biological process as well as identification of new candidate hub genes in response to these complex processes. High throughput expression profiling data are highly useful for construction of co-expression networks. In the present study, we utilized transcriptome data for comprehensive regulatory network studies of MYB TFs by “top-down” and “guide-gene” approaches. More than 50% of OsMYBs were strongly correlated under 50 experimental conditions with 51 hub genes via “top-down” approach. Further, clusters were identified using Markov Clustering (MCL). To maximize the clustering performance, parameter evaluation of the MCL inflation score (I) was performed in terms of enriched GO categories by measuring F-score. Comparison of co-expressed cluster and clads analyzed from phylogenetic analysis signifies their evolutionarily conserved co-regulatory role. We utilized compendium of known interaction and biological role with Gene Ontology enrichment analysis to hypothesize function of coexpressed OsMYBs. In the other part, the transcriptional regulatory network analysis by “guide-gene” approach revealed 40 putative targets of 26 OsMYB TF hubs with high correlation value utilizing 815 microarray data. The putative targets with MYB-binding cis-elements enrichment in their promoter region, functional co-occurrence as well as nuclear localization supports our finding. Specially, enrichment of MYB binding regions involved in drought-inducibility implying their regulatory role in drought

  5. DkMyb2 wound-induced transcription factor of persimmon (Diospyros kaki Thunb.), contributes to proanthocyanidin regulation.

    PubMed

    Akagi, Takashi; Ikegami, Ayako; Yonemori, Keizo

    2010-10-01

    Proanthocyanidins (PAs) are secondary metabolites that contribute to the protection of a plant against biotic and abiotic stresses. Persimmon (Diospyros kaki) accumulates abundant PAs in each plant organ, and some potential Myb-like transcription factors (Myb-TFs) involved in the production of PAs have been isolated. In this study, we aimed to molecularly characterize one of them, DkMyb2, which was placed in a subclade including a PA regulator of Arabidopsis (Arabidopsis thaliana), TRANSPARENT TESTA2 (TT2), and was co-induced with PA pathway genes after wound stress. Ectopic DkMyb2 overexpression caused significant up-regulation of PA pathway genes in transgenic persimmon calluses and significant accumulation of PA, and increased mean degree of polymerization of PAs in transgenic kiwifruit calluses. Analysis of the DNA-binding ability of DkMyb2 by electrophoretic mobility shift assays showed that DkMyb2 directly binds to the AC-rich cis-motifs known as AC elements in the promoters of the two PA pathway genes in persimmon, DkANR, and DkLAR. Furthermore, a transient reporter assay using a dual-luciferase system demonstrated direct transcriptional activation of DkANR and DkLAR by DkMyb2. We also discuss subfunctionalization of two PA regulators in persimmon, DkMyb2 and DkMyb4, as well as PA regulators in other plant species from the viewpoint of their ability to bind to cis-motifs and their functions in transcriptional activation. Our results provide insight into the multiple regulatory mechanisms that control PA metabolism by Myb-TFs in persimmon.

  6. MYB75 Functions in Regulation of Secondary Cell Wall Formation in the Arabidopsis Inflorescence Stem1[W

    PubMed Central

    Bhargava, Apurva; Mansfield, Shawn D.; Hall, Hardy C.; Douglas, Carl J.; Ellis, Brian E.

    2010-01-01

    Deposition of lignified secondary cell walls in plants involves a major commitment of carbon skeletons in both the form of polysaccharides and phenylpropanoid constituents. This process is spatially and temporally regulated by transcription factors, including a number of MYB family transcription factors. MYB75, also called PRODUCTION OF ANTHOCYANIN PIGMENT1, is a known regulator of the anthocyanin branch of the phenylpropanoid pathway in Arabidopsis (Arabidopsis thaliana), but how this regulation might impact other aspects of carbon metabolism is unclear. We established that a loss-of-function mutation in MYB75 (myb75-1) results in increased cell wall thickness in xylary and interfascicular fibers within the inflorescence stem. The total lignin content and S/G ratio of the lignin monomers were also affected. Transcript profiles from the myb75-1 inflorescence stem revealed marked up-regulation in the expression of a suite of genes associated with lignin biosynthesis and cellulose deposition, as well as cell wall modifying proteins and genes involved in photosynthesis and carbon assimilation. These patterns suggest that MYB75 acts as a repressor of the lignin branch of the phenylpropanoid pathway. Since MYB75 physically interacts with another secondary cell wall regulator, the KNOX transcription factor KNAT7, these regulatory proteins may form functional complexes that contribute to the regulation of secondary cell wall deposition in the Arabidopsis inflorescence stem and that integrate the metabolic flux through the lignin, flavonoid, and polysaccharide pathways. PMID:20807862

  7. Functional Characterization of NAC and MYB Transcription Factors Involved in Regulation of Biomass Production in Switchgrass (Panicum virgatum)

    PubMed Central

    Zhong, Ruiqin; Yuan, Youxi; Spiekerman, John J.; Guley, Joshua T.; Egbosiuba, Janefrances C.; Ye, Zheng-Hua

    2015-01-01

    Switchgrass is a promising biofuel feedstock due to its high biomass production and low agronomic input requirements. Because the bulk of switchgrass biomass used for biofuel production is lignocellulosic secondary walls, studies on secondary wall biosynthesis and its transcriptional regulation are imperative for designing strategies for genetic improvement of biomass production in switchgrass. Here, we report the identification and functional characterization of a group of switchgrass transcription factors, including several NACs (PvSWNs) and a MYB (PvMYB46A), for their involvement in regulating secondary wall biosynthesis. PvSWNs and PvMYB46A were found to be highly expressed in stems and their expression was closely associated with sclerenchyma cells. Overexpression of PvSWNs and PvMYB46A in Arabidopsis was shown to result in activation of the biosynthetic genes for cellulose, xylan and lignin and ectopic deposition of secondary walls in normally parenchymatous cells. Transactivation and complementation studies demonstrated that PvSWNs were able to activate the SNBE-driven GUS reporter gene and effectively rescue the secondary wall defects in the Arabidopsis snd1 nst1 double mutant, indicating that they are functional orthologs of Arabidopsis SWNs. Furthermore, we showed that PvMYB46A could activate the SMRE-driven GUS reporter gene and complement the Arabidopsis myb46 myb83 double mutant, suggesting that it is a functional ortholog of Arabidopsis MYB46/MYB83. Together, these results indicate that PvSWNs and PvMYB46A are transcriptional switches involved in regulating secondary wall biosynthesis, which provides molecular tools for genetic manipulation of biomass production in switchgrass. PMID:26248336

  8. Methylation Affects Transposition and Splicing of a Large CACTA Transposon from a MYB Transcription Factor Regulating Anthocyanin Synthase Genes in Soybean Seed Coats

    PubMed Central

    Zabala, Gracia; Vodkin, Lila O.

    2014-01-01

    We determined the molecular basis of three soybean lines that vary in seed coat color at the R locus which is thought to encode a MYB transcription factor. RM55-rm is homozygous for a mutable allele (rm) that specifies black and brown striped seeds; RM30-R* is a stable black revertant isoline derived from the mutable line; and RM38-r has brown seed coats due to a recessive r allele shown to translate a truncated MYB protein. Using long range PCR, 454 sequencing of amplicons, and whole genome re-sequencing, we determined that the variegated RM55-rm line had a 13 kb CACTA subfamily transposon insertion (designated TgmR*) at a position 110 bp from the beginning of Intron2 of the R locus, Glyma09g36983. Although the MYB encoded by R was expressed at only very low levels in older seed coats of the black revertant RM30-R* line, it upregulated expression of anthocyanidin synthase genes (ANS2, ANS3) to promote the synthesis of anthocyanins. Surprisingly, the RM30-R* revertant also carried the 13 kb TgmR* insertion in Intron2. Using RNA-Seq, we showed that intron splicing was accurate, albeit at lower levels, despite the presence of the 13 kb TgmR* element. As determined by whole genome methylation sequencing, we demonstrate that the TgmR* sequence was relatively more methylated in RM30-R* than in the mutable RM55-rm progenitor line. The stabilized and more methylated RM30-R* revertant line apparently lacks effective binding of a transposae to its subterminal repeats, thus allowing intron splicing to proceed resulting in sufficient MYB protein to stimulate anthocyanin production and thus black seed coats. In this regard, the TgmR* element in soybean resembles McClintock's Spm-suppressible and change-of-state alleles of maize. This comparison explains the opposite effects of the TgmR* element on intron splicing of the MYB gene in which it resides depending on the methylation state of the element. PMID:25369033

  9. An R2R3 MYB transcription factor in wheat, TaPIMP1, mediates host resistance to Bipolaris sorokiniana and drought stresses through regulation of defense- and stress-related genes.

    PubMed

    Zhang, Zengyan; Liu, Xin; Wang, Xindong; Zhou, Miaoping; Zhou, Xianyao; Ye, Xingguo; Wei, Xuening

    2012-12-01

    In this study, we report new insights into the function of a wheat (Triticum aestivum) MYB gene TaPIMP1 through overexpression and underexpression, and its underlying mechanism in wheat. Electrophoretic mobility shift and yeast-one-hybrid assays indicated that TaPIMP1 can bind to five MYB-binding sites including ACI, and activate the expression of the genes with the cis-element, confirming that TaPIMP1 is an MYB transcription activator. TaPIMP1-overexpressing transgenic wheat exhibited significantly enhanced resistance to the fungal pathogen Bipolaris sorokiniana and drought stresses, whereas TaPIMP1-underexpressing transgenic wheat showed more susceptibility to the stresses compared with untransformed wheat, revealing that TaPIMP1 positively modulates host-defense responses to B. sorokiniana and drought stresses. Microarray analysis showed that a subset of defense- and stress-related genes were up-regulated by TaPIMP1. These genes, including TaPIMP1, RD22, TLP4 and PR1a, were regulated by ABA and salicylic acid (SA). TaPIMP1-underexpressing transgenic wheat showed compromised induction of these stress-responsive genes following ABA and SA treatments. In summary, TaPIMP1, as a positive molecular linker, mediates resistance to B. sorokiniana and drought stresses by regulation of stress-related genes in ABA- and SA-signaling pathways in wheat. Furthermore, TaPIMP1 may provide a transgenic tool for engineering multiple-resistance wheat in breeding programs.

  10. Molecular basis of the recognition of the ap65-1 gene transcription promoter elements by a Myb protein from the protozoan parasite Trichomonas vaginalis.

    PubMed

    Jiang, Ingjye; Tsai, Chen-Kun; Chen, Sheng-Chia; Wang, Szu-Huan; Amiraslanov, Imamaddin; Chang, Chi-Fon; Wu, Wen-Jin; Tai, Jung-Hsiang; Liaw, Yen-Chywan; Huang, Tai-Huang

    2011-11-01

    Iron-inducible transcription of the ap65-1 gene in Trichomonas vaginalis involves at least three Myb-like transcriptional factors (tvMyb1, tvMyb2 and tvMyb3) that differentially bind to two closely spaced promoter sites, MRE-1/MRE-2r and MRE-2f. Here, we defined a fragment of tvMyb2 comprising residues 40-156 (tvMyb2₄₀₋₁₅₆) as the minimum structural unit that retains near full binding affinity with the promoter DNAs. Like c-Myb in vertebrates, the DNA-free tvMyb2₄₀₋₁₅₆ has a flexible and open conformation. Upon binding to the promoter DNA elements, tvMyb2₄₀₋₁₅₆ undergoes significant conformational re-arrangement and structure stabilization. Crystal structures of tvMyb2₄₀₋₁₅₆ in complex with promoter element-containing DNA oligomers showed that 5'-a/gACGAT-3' is the specific base sequence recognized by tvMyb2₄₀₋₁₅₆, which does not fully conform to that of the Myb binding site sequence. Furthermore, Lys⁴⁹, which is upstream of the R2 motif (amino acids 52-102) also participates in specific DNA sequence recognition. Intriguingly, tvMyb2₄₀₋₁₅₆ binds to the promoter elements in an orientation opposite to that proposed in the HADDOCK model of the tvMyb1₃₅₋₁₄₁/MRE-1-MRE-2r complex. These results shed new light on understanding the molecular mechanism of Myb-DNA recognition and provide a framework to study the molecular basis of transcriptional regulation of myriad Mybs in T. vaginalis. PMID:21771861

  11. Functional analysis of the seed coat-specific gene GbMYB2 from cotton.

    PubMed

    Huang, Yiqun; Liu, Xiang; Tang, Kexuan; Zuo, Kaijing

    2013-12-01

    MYB transcription factors are essential for cotton fiber development. We isolated the R2R3-MYB gene GbMYB2 from Gossypium barbadense. RNA in situ hybridization analysis showed that GbMYB2 is mainly expressed in the outer integuments of cotton ovules and in elongating fibers. GbMYB2 expression increased throughout fiber initiation and during the elongation stage. The expression level of GbMYB2 was higher in the Gossypium hirsutum cultivar Xu142 than in the Xu142 (fl) mutant. Overexpression of GbMYB2 in Arabidopsis caused thicker leaf trichomes and longer roots to develop due to the activation of trichome development-related genes such as GL2. These results indicate that GbMYB2 is an R2R3-MYB gene that is involved in fiber development.

  12. The cotton MYB108 forms a positive feedback regulation loop with CML11 and participates in the defense response against Verticillium dahliae infection.

    PubMed

    Cheng, Huan-Qing; Han, Li-Bo; Yang, Chun-Lin; Wu, Xiao-Min; Zhong, Nai-Qin; Wu, Jia-He; Wang, Fu-Xin; Wang, Hai-Yun; Xia, Gui-Xian

    2016-03-01

    Accumulating evidence indicates that plant MYB transcription factors participate in defense against pathogen attack, but their regulatory targets and related signaling processes remain largely unknown. Here, we identified a defense-related MYB gene (GhMYB108) from upland cotton (Gossypium hirsutum) and characterized its functional mechanism. Expression of GhMYB108 in cotton plants was induced by Verticillium dahliae infection and responded to the application of defense signaling molecules, including salicylic acid, jasmonic acid, and ethylene. Knockdown of GhMYB108 expression led to increased susceptibility of cotton plants to V. dahliae, while ecotopic overexpression of GhMYB108 in Arabidopsis thaliana conferred enhanced tolerance to the pathogen. Further analysis demonstrated that GhMYB108 interacted with the calmodulin-like protein GhCML11, and the two proteins form a positive feedback loop to enhance the transcription of GhCML11 in a calcium-dependent manner. Verticillium dahliae infection stimulated Ca(2+) influx into the cytosol in cotton root cells, but this response was disrupted in both GhCML11-silenced plants and GhMYB108-silenced plants in which expression of several calcium signaling-related genes was down-regulated. Taken together, these results indicate that GhMYB108 acts as a positive regulator in defense against V. dahliae infection by interacting with GhCML11. Furthermore, the data also revealed the important roles and synergetic regulation of MYB transcription factor, Ca(2+), and calmodulin in plant immune responses.

  13. Peach MYB7 activates transcription of the proanthocyanidin pathway gene encoding leucoanthocyanidin reductase, but not anthocyanidin reductase

    PubMed Central

    Zhou, Hui; Lin-Wang, Kui; Liao, Liao; Gu, Chao; Lu, Ziqi; Allan, Andrew C.; Han, Yuepeng

    2015-01-01

    Proanthocyanidins (PAs) are a group of natural phenolic compounds that have a great effect on both flavor and nutritious value of fruit. It has been shown that PA synthesis is regulated by R2R3-MYB transcription factors (TFs) via activation of PA-specific pathway genes encoding leucoanthocyanidin reductase and anthocyanidin reductase. Here, we report the isolation and characterization of a MYB gene designated PpMYB7 in peach. The peach PpMYB7 represents a new group of R2R3-MYB genes regulating PA synthesis in plants. It is able to activate transcription of PpLAR1 but not PpANR, and has a broader selection of potential bHLH partners compared with PpMYBPA1. Transcription of PpMYB7 can be activated by the peach basic leucine-zipper 5 TF (PpbZIP5) via response to ABA. Our study suggests a transcriptional network regulating PA synthesis in peach, with the results aiding the understanding of the functional divergence between R2R3-MYB TFs in plants. PMID:26579158

  14. The R2R3-type MYB gene OsMYB91 has a function in coordinating plant growth and salt stress tolerance in rice.

    PubMed

    Zhu, Ning; Cheng, Saifeng; Liu, Xiaoyun; Du, Hao; Dai, Mingqiu; Zhou, Dao-Xiu; Yang, Wenjing; Zhao, Yu

    2015-07-01

    Plants have evolved a number of different mechanisms to respond and to adapt to abiotic stress for their survival. However, the regulatory mechanisms involved in coordinating abiotic stress tolerance and plant growth are not fully understood. Here, the function of OsMYB91, an R2R3-type MYB transcription factor of rice was explored. OsMYB91 was induced by abiotic stress, especially by salt stress. Analysis of chromatin structure of the gene revealed that salt stress led to rapid removal of DNA methylation from the promoter region and rapid changes of histone modifications in the locus. Plants over-expressing OsMYB91 showed reduced plant growth and accumulation of endogenous ABA under control conditions. Under salt stress, the over-expression plants showed enhanced tolerance with significant increases of proline levels and a highly enhanced capacity to scavenge active oxygen as well as the increased induction of OsP5CS1 and LOC_Os03g44130 compared to wild type, while RNAi plants were less sensitive. In addition, expression of OsMYB91 was also induced by other abiotic stresses and hormone treatment. More interestingly, SLR1, the rice homolog of Arabidopsis DELLA genes that have been shown to integrate endogenous developmental signals with adverse environmental conditions, was highly induced by OsMYB91 over-expression, while the salt-induction of SLR1 expression was impaired in the RNAi plants. These results suggested that OsMYB91 was a stress-responsive gene that might be involved in coordinating rice tolerance to abiotic stress and plant growth by regulating SLR1 expression.

  15. VIGS approach reveals the modulation of anthocyanin biosynthetic genes by CaMYB in chili pepper leaves

    PubMed Central

    Zhang, Zhen; Li, Da-Wei; Jin, Jing-Hao; Yin, Yan-Xu; Zhang, Huai-Xia; Chai, Wei-Guo; Gong, Zhen-Hui

    2015-01-01

    The purple coloration of pepper leaves arises from the accumulation of anthocyanin. Three regulatory and 12 structural genes have been characterized for their involvement in the anthocyanin biosynthesis. Examination of the abundance of these genes in leaves showed that the majority of them differed between anthocyanin pigmented line Z1 and non-pigmented line A3. Silencing of the R2R3-MYB transcription factor CaMYB in pepper leaves of Z1 resulted in the loss of anthocyanin accumulation. Moreover, the expression of multiple genes was altered in the silenced leaves. The expression of MYC was significantly lower in CaMYB-silenced leaves, whereas WD40 showed the opposite pattern. Most structural genes including CHS, CHI, F3H, F3′5′H, DFR, ANS, UFGT, ANP, and GST were repressed in CaMYB-silenced foliage with the exception of PAL, C4H, and 4CL. These results indicated that MYB plays an important role in the regulation of anthocyanin biosynthetic related genes. Besides CaMYB silenced leaves rendered more sporulation of Phytophthora capsici Leonian indicating that CaMYB might be involved in the defense response to pathogens. PMID:26217354

  16. VIGS approach reveals the modulation of anthocyanin biosynthetic genes by CaMYB in chili pepper leaves.

    PubMed

    Zhang, Zhen; Li, Da-Wei; Jin, Jing-Hao; Yin, Yan-Xu; Zhang, Huai-Xia; Chai, Wei-Guo; Gong, Zhen-Hui

    2015-01-01

    The purple coloration of pepper leaves arises from the accumulation of anthocyanin. Three regulatory and 12 structural genes have been characterized for their involvement in the anthocyanin biosynthesis. Examination of the abundance of these genes in leaves showed that the majority of them differed between anthocyanin pigmented line Z1 and non-pigmented line A3. Silencing of the R2R3-MYB transcription factor CaMYB in pepper leaves of Z1 resulted in the loss of anthocyanin accumulation. Moreover, the expression of multiple genes was altered in the silenced leaves. The expression of MYC was significantly lower in CaMYB-silenced leaves, whereas WD40 showed the opposite pattern. Most structural genes including CHS, CHI, F3H, F3'5'H, DFR, ANS, UFGT, ANP, and GST were repressed in CaMYB-silenced foliage with the exception of PAL, C4H, and 4CL. These results indicated that MYB plays an important role in the regulation of anthocyanin biosynthetic related genes. Besides CaMYB silenced leaves rendered more sporulation of Phytophthora capsici Leonian indicating that CaMYB might be involved in the defense response to pathogens. PMID:26217354

  17. Genome Wide Analysis of the Apple MYB Transcription Factor Family Allows the Identification of MdoMYB121 Gene Confering Abiotic Stress Tolerance in Plants

    PubMed Central

    Wang, Rong-Kai; Zhang, Rui-Fen; Hao, Yu-Jin

    2013-01-01

    The MYB proteins comprise one of the largest families of transcription factors (TFs) in plants. Although several MYB genes have been characterized to play roles in secondary metabolism, the MYB family has not yet been identified in apple. In this study, 229 apple MYB genes were identified through a genome-wide analysis and divided into 45 subgroups. A computational analysis was conducted using the apple genomic database to yield a complete overview of the MYB family, including the intron-exon organizations, the sequence features of the MYB DNA-binding domains, the carboxy-terminal motifs, and the chromosomal locations. Subsequently, the expression of 18 MYB genes, including 12 were chosen from stress-related subgroups, while another 6 ones from other subgroups, in response to various abiotic stresses was examined. It was found that several of these MYB genes, particularly MdoMYB121, were induced by multiple stresses. The MdoMYB121 was then further functionally characterized. Its predicted protein was found to be localized in the nucleus. A transgenic analysis indicated that the overexpression of the MdoMYB121 gene remarkably enhanced the tolerance to high salinity, drought, and cold stresses in transgenic tomato and apple plants. Our results indicate that the MYB genes are highly conserved in plant species and that MdoMYB121 can be used as a target gene in genetic engineering approaches to improve the tolerance of plants to multiple abiotic stresses. PMID:23950843

  18. Genome-wide analysis of the MYB gene family in physic nut (Jatropha curcas L.).

    PubMed

    Zhou, Changpin; Chen, Yanbo; Wu, Zhenying; Lu, Wenjia; Han, Jinli; Wu, Pingzhi; Chen, Yaping; Li, Meiru; Jiang, Huawu; Wu, Guojiang

    2015-11-01

    The MYB proteins comprise one of the largest transcription factor families in plants, and play key roles in regulatory networks controlling development, metabolism, and stress responses. A total of 125 MYB genes (JcMYB) have been identified in the physic nut (Jatropha curcas L.) genome, including 120 2R-type MYB, 4 3R-MYB, and 1 4R-MYB genes. Based on exon-intron arrangement of MYBs from both lower (Physcomitrella patens) and higher (physic nut, Arabidopsis, and rice) plants, we can classify plant MYB genes into ten groups (MI-X), except for MIX genes which are nonexistent in higher plants. We also observed that MVIII genes may be one of the most ancient MYB types which consist of both R2R3- and 3R-MYB genes. Most MYB genes (76.8% in physic nut) belong to the MI group which can be divided into 34 subgroups. The JcMYB genes were nonrandomly distributed on its 11 linkage groups (LGs). The expansion of MYB genes across several subgroups was observed and resulted from genome triplication of ancient dicotyledons and from both ancient and recent tandem duplication events in the physic nut genome. The expression patterns of several MYB duplicates in the physic nut showed differences in four tissues (root, stem, leaf, and seed), and 34 MYB genes responded to at least one abiotic stressor (drought, salinity, phosphate starvation, and nitrogen starvation) in leaves and/or roots based on the data analysis of digital gene expression tags. Overexpression of the JcMYB001 gene in Arabidopsis increased its sensitivity to drought and salinity stresses. PMID:26142104

  19. Genome-wide analysis of the MYB gene family in physic nut (Jatropha curcas L.).

    PubMed

    Zhou, Changpin; Chen, Yanbo; Wu, Zhenying; Lu, Wenjia; Han, Jinli; Wu, Pingzhi; Chen, Yaping; Li, Meiru; Jiang, Huawu; Wu, Guojiang

    2015-11-01

    The MYB proteins comprise one of the largest transcription factor families in plants, and play key roles in regulatory networks controlling development, metabolism, and stress responses. A total of 125 MYB genes (JcMYB) have been identified in the physic nut (Jatropha curcas L.) genome, including 120 2R-type MYB, 4 3R-MYB, and 1 4R-MYB genes. Based on exon-intron arrangement of MYBs from both lower (Physcomitrella patens) and higher (physic nut, Arabidopsis, and rice) plants, we can classify plant MYB genes into ten groups (MI-X), except for MIX genes which are nonexistent in higher plants. We also observed that MVIII genes may be one of the most ancient MYB types which consist of both R2R3- and 3R-MYB genes. Most MYB genes (76.8% in physic nut) belong to the MI group which can be divided into 34 subgroups. The JcMYB genes were nonrandomly distributed on its 11 linkage groups (LGs). The expansion of MYB genes across several subgroups was observed and resulted from genome triplication of ancient dicotyledons and from both ancient and recent tandem duplication events in the physic nut genome. The expression patterns of several MYB duplicates in the physic nut showed differences in four tissues (root, stem, leaf, and seed), and 34 MYB genes responded to at least one abiotic stressor (drought, salinity, phosphate starvation, and nitrogen starvation) in leaves and/or roots based on the data analysis of digital gene expression tags. Overexpression of the JcMYB001 gene in Arabidopsis increased its sensitivity to drought and salinity stresses.

  20. Developmentally distinct MYB genes encode functionally equivalent proteins in Arabidopsis.

    PubMed

    Lee, M M; Schiefelbein, J

    2001-05-01

    The duplication and divergence of developmental control genes is thought to have driven morphological diversification during the evolution of multicellular organisms. To examine the molecular basis of this process, we analyzed the functional relationship between two paralogous MYB transcription factor genes, WEREWOLF (WER) and GLABROUS1 (GL1), in Arabidopsis. The WER and GL1 genes specify distinct cell types and exhibit non-overlapping expression patterns during Arabidopsis development. Nevertheless, reciprocal complementation experiments with a series of gene fusions showed that WER and GL1 encode functionally equivalent proteins, and their unique roles in plant development are entirely due to differences in their cis-regulatory sequences. Similar experiments with a distantly related MYB gene (MYB2) showed that its product cannot functionally substitute for WER or GL1. Furthermore, an analysis of the WER and GL1 proteins shows that conserved sequences correspond to specific functional domains. These results provide new insights into the evolution of the MYB gene family in Arabidopsis, and, more generally, they demonstrate that novel developmental gene function may arise solely by the modification of cis-regulatory sequences.

  1. c-myb stimulates cell growth by regulation of insulin-like growth factor (IGF) and IGF-binding protein-3 in K562 leukemia cells

    SciTech Connect

    Kim, Min-Sun; Kim, Sun-Young; Arunachalam, Sankarganesh; Hwang, Pyoung-Han; Yi, Ho-Keun; Nam, Sang-Yun; Lee, Dae-Yeol

    2009-07-17

    c-myb plays an important role in the regulation of cell growth and differentiation, and is highly expressed in immature hematopoietic cells. The human chronic myelogenous leukemia cell K562, highly expresses IGF-I, IGF-II, IGF-IR, and IGF-induced cellular proliferation is mediated by IGF-IR. To characterize the impact of c-myb on the IGF-IGFBP-3 axis in leukemia cells, we overexpressed c-myb using an adenovirus gene transfer system in K562 cells. The overexpression of c-myb induced cell proliferation, compared to control, and c-myb induced cell growth was inhibited by anti-IGF-IR antibodies. c-myb overexpression resulted in a significant increase in the expression of IGF-I, IGF-II, and IGF-IR, and a decrease in IGFBP-3 expression. By contrast, disruption of c-myb function by DN-myb overexpression resulted in significant reduction of IGF-I, IGF-II, IGF-IR, and elevation of IGFBP-3 expression. In addition, exogenous IGFBP-3 inhibited the proliferation of K562 cells, and c-myb induced cell growth was blocked by IGFBP-3 overexpression in a dose-dependent manner. The growth-promoting effects of c-myb were mediated through two major intracellular signaling pathways, Akt and Erk. Activation of Akt and Erk by c-myb was completely blocked by IGF-IR and IGFBP-3 antibodies. These findings suggest that c-myb stimulates cell growth, in part, by regulating expression of the components of IGF-IGFBP axis in K562 cells. In addition, disruption of c-myb function by DN-myb may provide a useful strategy for treatment of leukemia.

  2. MdMYB9 and MdMYB11 are involved in the regulation of the JA-induced biosynthesis of anthocyanin and proanthocyanidin in apples.

    PubMed

    An, Xiu-Hong; Tian, Yi; Chen, Ke-Qin; Liu, Xiao-Juan; Liu, Dan-Dan; Xie, Xing-Bin; Cheng, Cun-Gang; Cong, Pei-Hua; Hao, Yu-Jin

    2015-04-01

    Anthocyanin and proanthocyanidin (PA) are important secondary metabolites and beneficial to human health. Their biosynthesis is induced by jasmonate (JA) treatment and regulated by MYB transcription factors (TFs). However, which and how MYB TFs regulate this process is largely unknown in apple. In this study, MdMYB9 and MdMYB11 which were induced by methyl jasmonate (MeJA) were functionally characterized. Overexpression of MdMYB9 or MdMYB11 promoted not only anthocyanin but also PA accumulation in apple calluses, and the accumulation was further enhanced by MeJA. Subsequently, yeast two-hybrid, pull-down and bimolecular fluorescence complementation assays showed that both MYB proteins interact with MdbHLH3. Moreover, Jasmonate ZIM-domain (MdJAZ) proteins interact with MdbHLH3. Furthermore, chromatin immunoprecipitation-quantitative PCR and yeast one-hybrid assays demonstrated that both MdMYB9 and MdMYB11 bind to the promoters of ANS, ANR and LAR, whereas MdbHLH3 is recruited to the promoters of MdMYB9 and MdMYB11 and regulates their transcription. In addition, transient expression assays indicated that overexpression of MdJAZ2 inhibits the recruitment of MdbHLH3 to the promoters of MdMYB9 and MdMYB11. Our findings provide new insight into the mechanism of how MeJA regulates anthocyanin and PA accumulation in apple. PMID:25527830

  3. MdMYB9 and MdMYB11 are involved in the regulation of the JA-induced biosynthesis of anthocyanin and proanthocyanidin in apples.

    PubMed

    An, Xiu-Hong; Tian, Yi; Chen, Ke-Qin; Liu, Xiao-Juan; Liu, Dan-Dan; Xie, Xing-Bin; Cheng, Cun-Gang; Cong, Pei-Hua; Hao, Yu-Jin

    2015-04-01

    Anthocyanin and proanthocyanidin (PA) are important secondary metabolites and beneficial to human health. Their biosynthesis is induced by jasmonate (JA) treatment and regulated by MYB transcription factors (TFs). However, which and how MYB TFs regulate this process is largely unknown in apple. In this study, MdMYB9 and MdMYB11 which were induced by methyl jasmonate (MeJA) were functionally characterized. Overexpression of MdMYB9 or MdMYB11 promoted not only anthocyanin but also PA accumulation in apple calluses, and the accumulation was further enhanced by MeJA. Subsequently, yeast two-hybrid, pull-down and bimolecular fluorescence complementation assays showed that both MYB proteins interact with MdbHLH3. Moreover, Jasmonate ZIM-domain (MdJAZ) proteins interact with MdbHLH3. Furthermore, chromatin immunoprecipitation-quantitative PCR and yeast one-hybrid assays demonstrated that both MdMYB9 and MdMYB11 bind to the promoters of ANS, ANR and LAR, whereas MdbHLH3 is recruited to the promoters of MdMYB9 and MdMYB11 and regulates their transcription. In addition, transient expression assays indicated that overexpression of MdJAZ2 inhibits the recruitment of MdbHLH3 to the promoters of MdMYB9 and MdMYB11. Our findings provide new insight into the mechanism of how MeJA regulates anthocyanin and PA accumulation in apple.

  4. Genome-wide identification of cassava R2R3 MYB family genes related to abscission zone separation after environmental-stress-induced abscission.

    PubMed

    Liao, Wenbin; Yang, Yiling; Li, Yayun; Wang, Gan; Peng, Ming

    2016-01-01

    Cassava plants (Manihot esculenta Crantz) resist environmental stresses by shedding leaves in leaf pulvinus abscission zones (AZs), thus leading to adaptation to new environmental conditions. Little is known about the roles of cassava R2R3 MYB factors in regulating AZ separation. Herein, 166 cassava R2R3 MYB genes were identified. Evolutionary analysis indicated that the 166 R2R3 MYB genes could be divided into 11 subfamilies. Transcriptome analysis indicated that 26 R2R3 MYB genes were expressed in AZs across six time points during both ethylene- and water-deficit stress-induced leaf abscission. Comparative expression profile analysis of similar SOTA (Self Organizing Tree Algorithm) clusters demonstrated that 10 R2R3 MYB genes had similar expression patterns at six time points in response to both treatments. GO (Gene Ontology) annotation confirmed that all 10 R2R3 MYB genes participated in the responses to stress and ethylene and auxin stimuli. Analysis of the putative 10 R2R3 MYB promoter regions showed that those genes primarily contained ethylene- and stress-related cis-elements. The expression profiles of the genes acting downstream of the selected MYBs were confirmed to be involved in cassava abscission zone separation. All these results indicated that R2R3 MYB plays an important regulatory role in AZ separation. PMID:27573926

  5. Genome-wide identification of cassava R2R3 MYB family genes related to abscission zone separation after environmental-stress-induced abscission.

    PubMed

    Liao, Wenbin; Yang, Yiling; Li, Yayun; Wang, Gan; Peng, Ming

    2016-08-30

    Cassava plants (Manihot esculenta Crantz) resist environmental stresses by shedding leaves in leaf pulvinus abscission zones (AZs), thus leading to adaptation to new environmental conditions. Little is known about the roles of cassava R2R3 MYB factors in regulating AZ separation. Herein, 166 cassava R2R3 MYB genes were identified. Evolutionary analysis indicated that the 166 R2R3 MYB genes could be divided into 11 subfamilies. Transcriptome analysis indicated that 26 R2R3 MYB genes were expressed in AZs across six time points during both ethylene- and water-deficit stress-induced leaf abscission. Comparative expression profile analysis of similar SOTA (Self Organizing Tree Algorithm) clusters demonstrated that 10 R2R3 MYB genes had similar expression patterns at six time points in response to both treatments. GO (Gene Ontology) annotation confirmed that all 10 R2R3 MYB genes participated in the responses to stress and ethylene and auxin stimuli. Analysis of the putative 10 R2R3 MYB promoter regions showed that those genes primarily contained ethylene- and stress-related cis-elements. The expression profiles of the genes acting downstream of the selected MYBs were confirmed to be involved in cassava abscission zone separation. All these results indicated that R2R3 MYB plays an important regulatory role in AZ separation.

  6. Genome-wide identification of cassava R2R3 MYB family genes related to abscission zone separation after environmental-stress-induced abscission

    PubMed Central

    Liao, Wenbin; Yang, Yiling; Li, Yayun; Wang, Gan; Peng, Ming

    2016-01-01

    Cassava plants (Manihot esculenta Crantz) resist environmental stresses by shedding leaves in leaf pulvinus abscission zones (AZs), thus leading to adaptation to new environmental conditions. Little is known about the roles of cassava R2R3 MYB factors in regulating AZ separation. Herein, 166 cassava R2R3 MYB genes were identified. Evolutionary analysis indicated that the 166 R2R3 MYB genes could be divided into 11 subfamilies. Transcriptome analysis indicated that 26 R2R3 MYB genes were expressed in AZs across six time points during both ethylene- and water-deficit stress-induced leaf abscission. Comparative expression profile analysis of similar SOTA (Self Organizing Tree Algorithm) clusters demonstrated that 10 R2R3 MYB genes had similar expression patterns at six time points in response to both treatments. GO (Gene Ontology) annotation confirmed that all 10 R2R3 MYB genes participated in the responses to stress and ethylene and auxin stimuli. Analysis of the putative 10 R2R3 MYB promoter regions showed that those genes primarily contained ethylene- and stress-related cis-elements. The expression profiles of the genes acting downstream of the selected MYBs were confirmed to be involved in cassava abscission zone separation. All these results indicated that R2R3 MYB plays an important regulatory role in AZ separation. PMID:27573926

  7. Constitutive Activation of an Anthocyanin Regulatory Gene PcMYB10.6 Is Related to Red Coloration in Purple-Foliage Plum.

    PubMed

    Gu, Chao; Liao, Liao; Zhou, Hui; Wang, Lu; Deng, Xianbao; Han, Yuepeng

    2015-01-01

    Cherry plum is a popular ornamental tree worldwide and most cultivars are selected for purple foliage. Here, we report the investigation of molecular mechanism underlying red pigmentation in purple-leaf plum 'Ziyeli' (Prunus cerasifera Ehrhar f. atropurpurea (Jacq.) Rehd.), which shows red color pigmentation in fruit (flesh and skin) and foliage. Six anthocyanin-activating MYB genes, designated PcMYB10.1 to PcMYB10.6, were isolated based on RNA-Seq data from leaves of cv. Ziyeli. Of these PcMYB10 genes, five (PcMYB10.1 through PcMYB10.5) show distinct spatial and temporal expression patterns, while the PcMYB10.6 gene is highly expressed in all the purple-coloured organs of cv. Ziyeli. Constitutive activation of PcMYB10.6 is closely related to red pigmentation in the leaf, fruit (flesh and skin), and sepal. However, the PcMYB10.6 activation cannot induce red pigmentation in the petal of cv. Ziyeli during late stages of flower development due to due to a lack of expression of PcUFGT. The inhibition of red pigmentation in the petal of cherry plum could be attributed to the high-level expression of PcANR that directs anthocyanidin flux to proanthocyanidin biosynthesis. In addition, PcMYB10.2 is highly expressed in fruit and sepal, but its expression cannot induce red pigmentation. This suggests the PcMYB10 gene family in cherry plum may have diverged in function and PcMYB10.2 plays little role in the regulation of red pigmentation. Our study provides for the first time an example of constitutive activation of an anthocyanin-activating MYB gene in Prunus although its underlying mechanism remains unclear. PMID:26247780

  8. Constitutive Activation of an Anthocyanin Regulatory Gene PcMYB10.6 Is Related to Red Coloration in Purple-Foliage Plum

    PubMed Central

    Zhou, Hui; Wang, Lu; Deng, Xianbao; Han, Yuepeng

    2015-01-01

    Cherry plum is a popular ornamental tree worldwide and most cultivars are selected for purple foliage. Here, we report the investigation of molecular mechanism underlying red pigmentation in purple-leaf plum ‘Ziyeli’ (Prunus cerasifera Ehrhar f. atropurpurea (Jacq.) Rehd.), which shows red color pigmentation in fruit (flesh and skin) and foliage. Six anthocyanin-activating MYB genes, designated PcMYB10.1 to PcMYB10.6, were isolated based on RNA-Seq data from leaves of cv. Ziyeli. Of these PcMYB10 genes, five (PcMYB10.1 through PcMYB10.5) show distinct spatial and temporal expression patterns, while the PcMYB10.6 gene is highly expressed in all the purple-coloured organs of cv. Ziyeli. Constitutive activation of PcMYB10.6 is closely related to red pigmentation in the leaf, fruit (flesh and skin), and sepal. However, the PcMYB10.6 activation cannot induce red pigmentation in the petal of cv. Ziyeli during late stages of flower development due to due to a lack of expression of PcUFGT. The inhibition of red pigmentation in the petal of cherry plum could be attributed to the high-level expression of PcANR that directs anthocyanidin flux to proanthocyanidin biosynthesis. In addition, PcMYB10.2 is highly expressed in fruit and sepal, but its expression cannot induce red pigmentation. This suggests the PcMYB10 gene family in cherry plum may have diverged in function and PcMYB10.2 plays little role in the regulation of red pigmentation. Our study provides for the first time an example of constitutive activation of an anthocyanin-activating MYB gene in Prunus although its underlying mechanism remains unclear. PMID:26247780

  9. Molecular characterization of 60 isolated wheat MYB genes and analysis of their expression during abiotic stress

    PubMed Central

    Zhang, Lichao; Zhao, Guangyao; Jia, Jizeng; Liu, Xu; Kong, Xiuying

    2012-01-01

    The proteins of the MYB superfamily play central roles in developmental processes and defence responses in plants. Sixty unique wheat MYB genes that contain full-length cDNA sequences were isolated. These 60 genes were grouped into three categories, namely one R1R2R3-MYB, 22 R2R3-MYBs, and 37 MYB-related members. The sequence composition of the R2 and R3 repeats was conserved among the 22 wheat R2R3-MYB proteins. Phylogenetic comparison of the members of this superfamily among wheat, rice, and Arabidopsis revealed that the putative functions of some wheat MYB proteins were clustered into the Arabidopsis functional clades. Tissue-specific expression profiles showed that most of the wheat MYB genes were expressed in all of the tissues examined, suggesting that wheat MYB genes take part in multiple cellular processes. The expression analysis during abiotic stress identified a group of MYB genes that respond to one or more stress treatments. The overexpression of a salt-inducible gene, TaMYB32, enhanced the tolerance to salt stress in transgenic Arabidopsis. This study is the first comprehensive study of the MYB gene family in Triticeae. PMID:21934119

  10. A R2R3-MYB transcription factor from Epimedium sagittatum regulates the flavonoid biosynthetic pathway.

    PubMed

    Huang, Wenjun; Sun, Wei; Lv, Haiyan; Luo, Ming; Zeng, Shaohua; Pattanaik, Sitakanta; Yuan, Ling; Wang, Ying

    2013-01-01

    Herba epimedii (Epimedium), a traditional Chinese medicine, has been widely used as a kidney tonic and antirheumatic medicine for thousands of years. The bioactive components in herba epimedii are mainly prenylated flavonol glycosides, end-products of the flavonoid pathway. Epimedium species are also used as garden plants due to the colorful flowers and leaves. Many R2R3-MYB transcription factors (TFs) have been identified to regulate the flavonoid and anthocyanin biosynthetic pathways. However, little is known about the R2R3-MYB TFs involved in regulation of the flavonoid pathway in Epimedium. Here, we reported the isolation and functional characterization of the first R2R3-MYB TF (EsMYBA1) from Epimedium sagittatum (Sieb. Et Zucc.) Maxim. Conserved domains and phylogenetic analysis showed that EsMYBA1 belonged to the subgroup 6 clade (anthocyanin-related MYB clade) of R2R3-MYB family, which includes Arabidopsis AtPAP1, apple MdMYB10 and legume MtLAP1. EsMYBA1 was preferentially expressed in leaves, especially in red leaves that contain higher content of anthocyanin. Alternative splicing of EsMYBA1 resulted in three transcripts and two of them encoded a MYB-related protein. Yeast two-hybrid and transient luciferase expression assay showed that EsMYBA1 can interact with several bHLH regulators of the flavonoid pathway and activate the promoters of dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS). In both transgenic tobacco and Arabidopsis, overexpression of EsMYBA1 induced strong anthocyanin accumulation in reproductive and/or vegetative tissues via up-regulation of the main flavonoid-related genes. Furthermore, transient expression of EsMYBA1 in E. sagittatum leaves by Agrobacterium infiltration also induced anthocyanin accumulation in the wounded area. This first functional characterization of R2R3-MYB TFs in Epimedium species will promote further studies of the flavonoid biosynthesis and regulation in medicinal plants. PMID:23936468

  11. Distal regulation of c-myb expression during IL-6-induced differentiation in murine myeloid progenitor M1 cells

    PubMed Central

    Zhang, Junfang; Han, Bingshe; Li, Xiaoxia; Bies, Juraj; Jiang, Penglei; Koller, Richard P; Wolff, Linda

    2016-01-01

    The c-Myb transcription factor is a major regulator that controls differentiation and proliferation of hematopoietic progenitor cells, which is frequently deregulated in hematological diseases, such as lymphoma and leukemia. Understanding of the mechanisms regulating the transcription of c-myb gene is challenging as it lacks a typical promoter and multiple factors are involved. Our previous studies identified some distal regulatory elements in the upstream regions of c-myb gene in murine myeloid progenitor M1 cells, but the detailed mechanisms still remain unclear. In the present study, we found that a cell differentiation-related DNase1 hypersensitive site is located at a −28k region upstream of c-myb gene and that transcription factors Hoxa9, Meis1 and PU.1 bind to the −28k region. Circular chromosome conformation capture (4C) assay confirmed the interaction between the −28k region and the c-myb promoter, which is supported by the enrichment of CTCF and Cohesin. Our analysis also points to a critical role for Hoxa9 and PU.1 in distal regulation of c-myb expression in murine myeloid cells and cell differentiation. Overexpression of Hoxa9 disrupted the IL-6-induced differentiation of M1 cells and upregulated c-myb expression through binding of the −28k region. Taken together, our results provide an evidence for critical role of the −28k region in distal regulatory mechanism for c-myb gene expression during differentiation of myeloid progenitor M1 cells. PMID:27607579

  12. A systems-oriented analysis of the grapevine R2R3-MYB transcription factor family uncovers new insights into the regulation of stilbene accumulation

    PubMed Central

    Wong, Darren Chern Jan; Schlechter, Rudolf; Vannozzi, Alessandro; Höll, Janine; Hmmam, Ibrahim; Bogs, Jochen; Tornielli, Giovanni Battista; Castellarin, Simone Diego; Matus, José Tomás

    2016-01-01

    R2R3-MYB transcription factors (TFs) belong to a large and functionally diverse protein superfamily in plants. In this study, we explore the evolution and function of this family in grapevine (Vitis vinifera L.), a high-value fruit crop. We identified and manually curated 134 genes using RNA-Seq data, and named them systematically according to the Super-Nomenclature Committee. We identified novel genes, splicing variants and grapevine/woody-specific duplicated subgroups, suggesting possible neo- and sub-functionalization events. Regulatory network analysis ascribed biological functions to uncharacterized genes and validated those of known genes (e.g. secondary cell wall biogenesis and flavonoid biosynthesis). A comprehensive analysis of different MYB binding motifs in the promoters of co-expressed genes predicted grape R2R3-MYB binding preferences and supported evidence for putative downstream targets. Enrichment of cis-regulatory motifs for diverse TFs reinforced the notion of transcriptional coordination and interaction between MYBs and other regulators. Analysis of the network of Subgroup 2 showed that the resveratrol-related VviMYB14 and VviMYB15 share common co-expressed STILBENE SYNTHASE genes with the uncharacterized VviMYB13. These regulators have distinct expression patterns within organs and in response to biotic and abiotic stresses, suggesting a pivotal role of VviMYB13 in regulating stilbene accumulation in vegetative tissues and under biotic stress conditions. PMID:27407139

  13. Regulation of Cell Fate Determination by Single-Repeat R3 MYB Transcription Factors in Arabidopsis

    SciTech Connect

    Wang, Shucai; Chen, Jay

    2014-01-01

    MYB transcription factors regulate multiple aspects of plant growth and development. Among the large family of MYB transcription factors, single-repeat R3 MYB are characterized by their short sequence (<120 amino acids) consisting largely of the single MYB DNA-binding repeat. In the model plant Arabidopsis, R3 MYBs mediate lateral inhibition during epidermal patterning and are best characterized for their regulatory roles in trichome and root hair development. R3 MYBs act as negative regulators for trichome formation but as positive regulators for root hair development. In this article, we provide a comprehensive review on the role of R3 MYBs in the regulation of cell type specification in the model plant Arabidopsis.

  14. Regulation of cell fate determination by single-repeat R3 MYB transcription factors in Arabidopsis

    PubMed Central

    Wang, Shucai; Chen, Jin-Gui

    2014-01-01

    MYB transcription factors regulate multiple aspects of plant growth and development. Among the large family of MYB transcription factors, single-repeat R3 MYBs are characterized by their short sequence (<120 amino acids) consisting largely of the single MYB DNA-binding repeat. In the model plant Arabidopsis, R3 MYBs mediate lateral inhibition during epidermal patterning and are best characterized for their regulatory roles in trichome and root hair development. R3 MYBs act as negative regulators for trichome formation but as positive regulators for root hair development. In this article, we provide a comprehensive review on the role of R3 MYBs in the regulation of cell type specification in the model plant Arabidopsis. PMID:24782874

  15. Eafs Control Erythroid Cell Fate by Regulating c-myb Expression through Wnt Signaling

    PubMed Central

    Ma, Xufa; Liu, Jing-Xia

    2013-01-01

    ELL associated factor 1 and ELL associated factor 2 (EAF1/2 factors) are reported to play important roles in tumor suppression and embryogenesis. Our previous studies showed that eaf factors mediated effective convergence and extension (C&E) movements and modulated mesoderm and neural patterning by regulating both non-canonical and canonical Wnt signaling in the early embryonic process. In this study, through knockdown of both eaf1 and eaf2 in embryos, we found that differentiation of primary erythroid cells was blocked, but hematopoietic precursor cells maintained in eafs morphants. Co-injection of c-myb-MO rescued the erythroid differentiation in eafs morphants, as indicated by the restored expression of the erythroid-specific gene, βe3 globin. In addition, low dosage of c-myb effectively blocked the βe3 globin expression in embryos, and did not affect the expression of markers of hematopoietic progenitor cells and other mesoderm, which was similar to the phenotypes we observed in eafs morphants. We also revealed that knockdown Wnt signaling by transiently inducing dn-Tcf in embryos at the bud stage down-regulated the increased c-myb to normal level and also restored βe3 globin expression in eafs morphants. Our evidence points to a novel role for eaf factors in controlling erythroid cell fate by regulating c-Myb expression through canonic Wnt signaling. PMID:23717633

  16. Ectopic expression of R3 MYB transcription factor gene OsTCL1 in Arabidopsis, but not rice, affects trichome and root hair formation

    PubMed Central

    Zheng, Kaijie; Tian, Hainan; Hu, Qingnan; Guo, Hongyan; Yang, Li; Cai, Ling; Wang, Xutong; Liu, Bao; Wang, Shucai

    2016-01-01

    In Arabidopsis, a MYB-bHLH-WD40 (MBW) transcriptional activator complex activates the homeodomain protein gene GLABRA2 (GL2), leading to the promotion of trichome formation and inhibition of root hair formation. The same MBW complex also activates single-repeat R3 MYB genes. R3 MYBs in turn, play a negative feedback role by competing with R2R3 MYB proteins for binding bHLH proteins, thus blocking the formation of the MBW complex. By BLASTing the rice (Oryza sativa) protein database using the entire amino acid sequence of Arabidopsis R3 MYB transcription factor TRICHOMELESS1 (TCL1), we found that there are two genes in rice genome encoding R3 MYB transcription factors, namely Oryza sativa TRICHOMELESS1 (OsTCL1) and OsTCL2. Expressing OsTCL1 in Arabidopsis inhibited trichome formation and promoted root hair formation, and OsTCL1 interacted with GL3 when tested in Arabidopsis protoplasts. Consistent with these observations, expression levels of GL2, R2R3 MYB transcription factor gene GLABRA1 (GL1) and several R3 MYB genes were greatly reduced, indicating that OsTCL1 is functional R3 MYB. However, trichome and root hair formation in transgenic rice plants overexpressing OsTCL1 remained largely unchanged, and elevated expression of OsGL2 was observed in the transgenic rice plants, indicating that rice may use different mechanisms to regulate trichome formation. PMID:26758286

  17. Identification and expression analyses of MYB and WRKY transcription factor genes in Papaver somniferum L.

    PubMed

    Kakeshpour, Tayebeh; Nayebi, Shadi; Rashidi Monfared, Sajad; Moieni, Ahmad; Karimzadeh, Ghasem

    2015-10-01

    Papaver somniferum L. is an herbaceous, annual and diploid plant that is important from pharmacological and strategic point of view. The cDNA clones of two putative MYB and WRKY genes were isolated (GeneBank accession numbers KP411870 and KP203854, respectively) from this plant, via the nested-PCR method, and characterized. The MYB transcription factor (TF) comprises 342 amino acids, and exhibits the structural features of the R2R3MYB protein family. The WRKY TF, a 326 amino acid-long polypeptide, falls structurally into the group II of WRKY protein family. Quantitative real-time PCR (qRT-PCR) analyses indicate the presence of these TFs in all organs of P. somniferum L. and Papaver bracteatum L. Highest expression levels of these two TFs were observed in the leaf tissues of P. somniferum L. while in P. bracteatum L. the espression levels were highest in the root tissues. Promoter analysis of the 10 co-expressed gene clustered involved in noscapine biosynthesis pathway in P. somniferum L. suggested that not only these 10 genes are co-expressed, but also share common regulatory motifs and TFs including MYB and WRKY TFs, and that may explain their common regulation.

  18. Identification and expression analyses of MYB and WRKY transcription factor genes in Papaver somniferum L.

    PubMed

    Kakeshpour, Tayebeh; Nayebi, Shadi; Rashidi Monfared, Sajad; Moieni, Ahmad; Karimzadeh, Ghasem

    2015-10-01

    Papaver somniferum L. is an herbaceous, annual and diploid plant that is important from pharmacological and strategic point of view. The cDNA clones of two putative MYB and WRKY genes were isolated (GeneBank accession numbers KP411870 and KP203854, respectively) from this plant, via the nested-PCR method, and characterized. The MYB transcription factor (TF) comprises 342 amino acids, and exhibits the structural features of the R2R3MYB protein family. The WRKY TF, a 326 amino acid-long polypeptide, falls structurally into the group II of WRKY protein family. Quantitative real-time PCR (qRT-PCR) analyses indicate the presence of these TFs in all organs of P. somniferum L. and Papaver bracteatum L. Highest expression levels of these two TFs were observed in the leaf tissues of P. somniferum L. while in P. bracteatum L. the espression levels were highest in the root tissues. Promoter analysis of the 10 co-expressed gene clustered involved in noscapine biosynthesis pathway in P. somniferum L. suggested that not only these 10 genes are co-expressed, but also share common regulatory motifs and TFs including MYB and WRKY TFs, and that may explain their common regulation. PMID:26600674

  19. Regulation of CAPRICE transcription by MYB proteins for root epidermis differentiation in Arabidopsis.

    PubMed

    Koshino-Kimura, Yoshihiro; Wada, Takuji; Tachibana, Tatsuhiko; Tsugeki, Ryuji; Ishiguro, Sumie; Okada, Kiyotaka

    2005-06-01

    Epidermal cell differentiation in Arabidopsis root is studied as a model system for understanding cell fate specification. Two types of MYB-related transcription factors are involved in this cell differentiation. One of these, CAPRICE (CPC), encoding an R3-type MYB protein, is a positive regulator of hair cell differentiation and is preferentially transcribed in hairless cells. We analyzed the regulatory mechanism of CPC transcription. Deletion analyses of the CPC promoter revealed that hairless cell-specific transcription of the CPC gene required a 69 bp sequence, and a tandem repeat of this region was sufficient for its expression in epidermis. This region includes two MYB-binding sites, and the epidermis-specific transcription of CPC was abolished when base substitutions were introduced in these sites. We showed by gel mobility shift experiments and by yeast one-hybrid assay that WEREWOLF (WER), which is an R2R3-type MYB protein, directly binds to this region. We showed that WER also binds to the GL2 promoter region, indicating that WER directly regulates CPC and GL2 transcription by binding to their promoter regions.

  20. MYB82 functions in regulation of trichome development in Arabidopsis

    PubMed Central

    Liang, Gang; He, Hua; Li, Yang; Ai, Qin; Yu, Diqiu

    2014-01-01

    Trichome initiation and patterning are controlled by the TTG1–bHLH–MYB regulatory complex. Several MYB transcription factors have been determined to function in trichome development via incorporation into this complex. This study examined the role of MYB82, an R2R3-MYB transcription factor, in Arabidopsis trichome development. MYB82 was revealed to be a nuclear-localized transcription activator. Suppression of MYB82 function by fusion with a dominant repression domain (SRDX) resulted in glabrous leaves, as did overexpression of N-terminal-truncated MYB82. Overexpression of MYB82 genomic sequence, but not its cDNA sequence, led to reduced trichome numbers. Further investigation indicated that at least one of the two introns in MYB82 is essential to the protein’s trichome developmental function. An MYB-binding box was identified in the third exon of MYB82, which was inferred to be crucial for MYB82 function because the mutation of this box interfered with the ability of MYB82 to rescue the gl1 mutant. Protein interaction analysis revealed that MYB82 physically interacts with GLABRA3 (GL3). In addition, MYB82 and GL1 can form homodimers and heterodimers at R2R3-MYB domains, which may explain why their overexpression reduces trichome numbers. These results demonstrate the functional diversification of MYB82 and GL1 in trichome development. PMID:24803498

  1. An R2R3-MYB Transcription Factor Regulates Eugenol Production in Ripe Strawberry Fruit Receptacles.

    PubMed

    Medina-Puche, Laura; Molina-Hidalgo, Francisco Javier; Boersma, Maaike; Schuurink, Robert C; López-Vidriero, Irene; Solano, Roberto; Franco-Zorrilla, José-Manuel; Caballero, José Luis; Blanco-Portales, Rosario; Muñoz-Blanco, Juan

    2015-06-01

    Eugenol is a volatile phenylpropanoid that contributes to flower and ripe fruit scent. In ripe strawberry (Fragaria × ananassa) fruit receptacles, eugenol is biosynthesized by eugenol synthase (FaEGS2). However, the transcriptional regulation of this process is still unknown. We have identified and functionally characterized an R2R3 MYB transcription factor (emission of benzenoid II [FaEOBII]) that seems to be the orthologous gene of PhEOBII from Petunia hybrida, which contributes to the regulation of eugenol biosynthesis in petals. The expression of FaEOBII was ripening related and fruit receptacle specific, although high expression values were also found in petals. This expression pattern of FaEOBII correlated with eugenol content in both fruit receptacle and petals. The expression of FaEOBII was repressed by auxins and activated by abscisic acid, in parallel to the ripening process. In ripe strawberry receptacles, where the expression of FaEOBII was silenced, the expression of cinnamyl alcohol dehydrogenase1 and FaEGS2, two structural genes involved in eugenol production, was down-regulated. A subsequent decrease in eugenol content in ripe receptacles was also observed, confirming the involvement of FaEOBII in eugenol metabolism. Additionally, the expression of FaEOBII was under the control of FaMYB10, another R2R3 MYB transcription factor that regulates the early and late biosynthetic genes from the flavonoid/phenylpropanoid pathway. In parallel, the amount of eugenol in FaMYB10-silenced receptacles was also diminished. Taken together, these data indicate that FaEOBII plays a regulating role in the volatile phenylpropanoid pathway gene expression that gives rise to eugenol production in ripe strawberry receptacles. PMID:25931522

  2. An R2R3-MYB Transcription Factor Regulates Eugenol Production in Ripe Strawberry Fruit Receptacles.

    PubMed

    Medina-Puche, Laura; Molina-Hidalgo, Francisco Javier; Boersma, Maaike; Schuurink, Robert C; López-Vidriero, Irene; Solano, Roberto; Franco-Zorrilla, José-Manuel; Caballero, José Luis; Blanco-Portales, Rosario; Muñoz-Blanco, Juan

    2015-06-01

    Eugenol is a volatile phenylpropanoid that contributes to flower and ripe fruit scent. In ripe strawberry (Fragaria × ananassa) fruit receptacles, eugenol is biosynthesized by eugenol synthase (FaEGS2). However, the transcriptional regulation of this process is still unknown. We have identified and functionally characterized an R2R3 MYB transcription factor (emission of benzenoid II [FaEOBII]) that seems to be the orthologous gene of PhEOBII from Petunia hybrida, which contributes to the regulation of eugenol biosynthesis in petals. The expression of FaEOBII was ripening related and fruit receptacle specific, although high expression values were also found in petals. This expression pattern of FaEOBII correlated with eugenol content in both fruit receptacle and petals. The expression of FaEOBII was repressed by auxins and activated by abscisic acid, in parallel to the ripening process. In ripe strawberry receptacles, where the expression of FaEOBII was silenced, the expression of cinnamyl alcohol dehydrogenase1 and FaEGS2, two structural genes involved in eugenol production, was down-regulated. A subsequent decrease in eugenol content in ripe receptacles was also observed, confirming the involvement of FaEOBII in eugenol metabolism. Additionally, the expression of FaEOBII was under the control of FaMYB10, another R2R3 MYB transcription factor that regulates the early and late biosynthetic genes from the flavonoid/phenylpropanoid pathway. In parallel, the amount of eugenol in FaMYB10-silenced receptacles was also diminished. Taken together, these data indicate that FaEOBII plays a regulating role in the volatile phenylpropanoid pathway gene expression that gives rise to eugenol production in ripe strawberry receptacles.

  3. Over-expression of a subgroup 4 R2R3 type MYB transcription factor gene from Leucaena leucocephala reduces lignin content in transgenic tobacco.

    PubMed

    Omer, Sumita; Kumar, Santosh; Khan, Bashir M

    2013-01-01

    KEY MESSAGE : LlMYB1 , a subgroup 4 R2R3-type MYB transcription factor gene from Leucaena leucocephala appears to be a repressor of lignin biosynthesis pathway by regulating the transcription of general phenylpropanoid pathway genes. R2R3MYB transcription factors are known to play a wide role in regulating the phenylpropanoid pathway in plants. In this study, we report isolation, cloning and characterization of an R2R3MYB transcription factor gene (LlMYB1) from an economically important tree species, Leucaena leucocephala. LlMYB1 consists of 705 bp coding sequence corresponding to 235 amino acids. Sequence alignment revealed that the N-terminal (MYB) domain of the gene shares up to 95 % similarity with subgroup 4 (Sg4) members of R2R3Myb gene family functionally known to be lignin repressors. Highly divergent C-terminal region of the gene carried an ERF-associated amphiphilic repression (EAR) motif, another characteristic of the Sg4. The gene was phylogenetically grouped closest with AmMYB308, a known repressor of monolignol biosynthetic pathway genes. Spatio-temporal expression studies at different ages of seedlings using quantitative real-time PCR (QRT-PCR) showed highest transcript level of the gene in 10 day old stem tissues. Over-expression of the gene in transgenic tobacco showed statistically significant decline in the transcript levels of the general phenylpropanoid pathway genes and reduction in lignin content. Our study suggests that LlMYB1 might be playing the role of a repressor of lignin biosynthesis in L. leucocephala. PMID:23052594

  4. TaMYB13 is a transcriptional activator of fructosyltransferase genes involved in β-2,6-linked fructan synthesis in wheat.

    PubMed

    Xue, Gang-Ping; Kooiker, Maarten; Drenth, Janneke; McIntyre, C Lynne

    2011-12-01

    Fructans are soluble fructosyl-oligosaccharides deposited in many cool-season grass species as a carbon reserve; they are synthesised by fructosyltransferases. In wheat and barley fructans can accumulate in mature stems at a very high level and serve as an important carbon source for grain filling. Fructan synthesis in temperate cereals is regulated by sucrose level and developmental signals, and functions as a metabolic adjustment for carbon balance between carbon supply and sink demand. In this study the expression levels of a highly homologous group of Triticum aestivumMYB genes (TaMYB13-1, TaMYB13-2 and TaMYB13-3) were found to be positively correlated with the mRNA levels of sucrose:sucrose 1-fructosyltransferase (1-SST) and sucrose:fructan 6-fructosyltransferase (6-SFT) in wheat stems among recombinant inbred lines with a wide range of fructan concentrations through Affymetrix array expression analysis. This expression correction extended to expression profiles during stem development. TaMYB13 contains an R2R3-type MYB domain. In vitro random DNA-binding site selection followed by base substitution mutagenesis revealed that TaMYB13 bound to a (A/G/T)TT(A/T/C)GGT core sequence, which was present in the promoters of wheat Ta1-SST and Ta6-SFT genes as well as a barley Hv6-SFT gene. Transactivation analysis showed that TaMYB13 was a transcriptional activator and could markedly enhance the expression of 1-SST and 6-SFT promoter-driven reporter genes in wheat. Elimination of TaMYB13-binding sites in Ta6-SFT and Ta1-SST promoters markedly reduced TaMYB13-mediated reporter gene transactivation. These data suggest that TaMYB13 and its orthologues are positive regulators for controlling the expression of major fructosyltransferases involved in the fructan synthetic pathway in temperate cereals.

  5. A R2R3-MYB transcription factor, GmMYB12B2, affects the expression levels of flavonoid biosynthesis genes encoding key enzymes in transgenic Arabidopsis plants.

    PubMed

    Li, Xiao-Wei; Li, Jing-Wen; Zhai, Ying; Zhao, Yan; Zhao, Xu; Zhang, Hai-Jun; Su, Lian-Tai; Wang, Ying; Wang, Qing-Yu

    2013-12-10

    Isoflavones play diverse roles in plant-microbe interactions and are potentially important for human nutrition and health. To study the regulation of isoflavonoid synthesis in soybean, the R2R3-MYB transcription factor GmMYB12B2 was isolated and characterized. Yeast expression experiments demonstrated that GmMYB12B2 showed transcriptional activity. GmMYB12B2 was localized in the nucleus when it was transiently expressed in onion epidermal cells. Real-time quantitative PCR analysis revealed that GmMYB12B2 transcription was increased in roots and mature seeds compared with other organs. The gene expression level in immature embryos was consistent with the accumulation of isoflavones. CHS8 is a key enzyme in plant flavonoid biosynthesis. Transient expression experiments in soybean calli demonstrated that CHS8 was regulated by GmMYB12B2 and produced more fluorescence. The expression levels of some key enzymes in flavonoid biosynthesis were examined in transgenic Arabidopsis lines. The results showed that the expression levels of PAL1, CHS and FLS in transgenic plants were significantly higher than those in wild type plants. However, the expression level of DFR was lower, and the expression levels of CHI, F3H and F3'H were the same in all lines. GmMYB12B2 expression caused a constitutive increase in the accumulation of flavonoids in transgenic Arabidopsis lines compared with wild type plants. PMID:24060295

  6. A R2R3-MYB transcription factor, GmMYB12B2, affects the expression levels of flavonoid biosynthesis genes encoding key enzymes in transgenic Arabidopsis plants.

    PubMed

    Li, Xiao-Wei; Li, Jing-Wen; Zhai, Ying; Zhao, Yan; Zhao, Xu; Zhang, Hai-Jun; Su, Lian-Tai; Wang, Ying; Wang, Qing-Yu

    2013-12-10

    Isoflavones play diverse roles in plant-microbe interactions and are potentially important for human nutrition and health. To study the regulation of isoflavonoid synthesis in soybean, the R2R3-MYB transcription factor GmMYB12B2 was isolated and characterized. Yeast expression experiments demonstrated that GmMYB12B2 showed transcriptional activity. GmMYB12B2 was localized in the nucleus when it was transiently expressed in onion epidermal cells. Real-time quantitative PCR analysis revealed that GmMYB12B2 transcription was increased in roots and mature seeds compared with other organs. The gene expression level in immature embryos was consistent with the accumulation of isoflavones. CHS8 is a key enzyme in plant flavonoid biosynthesis. Transient expression experiments in soybean calli demonstrated that CHS8 was regulated by GmMYB12B2 and produced more fluorescence. The expression levels of some key enzymes in flavonoid biosynthesis were examined in transgenic Arabidopsis lines. The results showed that the expression levels of PAL1, CHS and FLS in transgenic plants were significantly higher than those in wild type plants. However, the expression level of DFR was lower, and the expression levels of CHI, F3H and F3'H were the same in all lines. GmMYB12B2 expression caused a constitutive increase in the accumulation of flavonoids in transgenic Arabidopsis lines compared with wild type plants.

  7. Identification and characterization of wheat drought-responsive MYB transcription factors involved in the regulation of cuticle biosynthesis

    PubMed Central

    Bi, Huihui; Luang, Sukanya; Li, Yuan; Bazanova, Natalia; Morran, Sarah; Song, Zhihong; Perera, M. Ann; Hrmova, Maria; Borisjuk, Nikolai; Lopato, Sergiy

    2016-01-01

    A plant cuticle forms a hydrophobic layer covering plant organs, and plays an important role in plant development and protection from environmental stresses. We examined epicuticular structure, composition, and a MYB-based regulatory network in two Australian wheat cultivars, RAC875 and Kukri, with contrasting cuticle appearance (glaucousness) and drought tolerance. Metabolomics and microscopic analyses of epicuticular waxes revealed that the content of β-diketones was the major compositional and structural difference between RAC875 and Kukri. The content of β-diketones remained the same while those of alkanes and primary alcohols were increased by drought in both cultivars, suggesting that the interplay of all components rather than a single one defines the difference in drought tolerance between cultivars. Six wheat genes encoding MYB transcription factors (TFs) were cloned; four of them were regulated in flag leaves of both cultivars by rapid dehydration and/or slowly developing cyclic drought. The involvement of selected MYB TFs in the regulation of cuticle biosynthesis was confirmed by a transient expression assay in wheat cell culture, using the promoters of wheat genes encoding cuticle biosynthesis-related enzymes and the SHINE1 (SHN1) TF. Two functional MYB-responsive elements, specifically recognized by TaMYB74 but not by other MYB TFs, were localized in the TdSHN1 promoter. Protein structural determinants underlying the binding specificity of TaMYB74 for functional DNA cis-elements were defined, using 3D protein molecular modelling. A scheme, linking drought-induced expression of the investigated TFs with downstream genes that participate in the synthesis of cuticle components, is proposed. PMID:27489236

  8. Mapping of an anthocyanin-regulating MYB transcription factor and its expression in red and green pear, Pyrus communis.

    PubMed

    Pierantoni, Luca; Dondini, Luca; De Franceschi, Paolo; Musacchi, Stefano; Winkel, Brenda S J; Sansavini, Silviero

    2010-12-01

    'Max Red Bartlett' is a red bud mutation of the yellow pear (Pyrus communis L.) cultivar 'Williams' (known as 'Bartlett' in North America). Anthocyanins are the most important pigments for red colour in fruits. Synthesis of anthocyanins is mediated by a number of well-characterized enzymes that include chalcone synthase (CHS), flavanone-3-hydroxylase (F3H), dihydroflavonol-4-reductase (DFR), anthocyanidin synthase (ANS), and UDP-glucose:flavonoid-3-O-glucosyltransferase (UFGT). Expression of the genes encoding these five enzymes was examined in pear fruit skin in order to elucidate the molecular mechanism for red coloration. In addition, the gene PcMYB10, encoding an R2R3 MYB transcription factor involved in anthocyanin biosynthetic pathway regulation, was isolated from both 'Williams' and 'Max Red Bartlett'. Analysis of the deduced amino acid sequence suggests that this gene is an ortholog of anthocyanin regulators known in other plant species. Its expression level was significantly higher in 'Max Red Bartlett' (red pear) compared with the original yellow variety 'Williams'. Although the map position of PcMYB10 corresponds to that of MdMYBa and MdMYB10, which control pigmentation of apple fruit skin, PcMYB10 is not directly responsible for red versus yellow colour in the two pear varieties, as the mutation underlying this difference maps to a different region of the pear genome.

  9. MYB10 plays a major role in the regulation of flavonoid/phenylpropanoid metabolism during ripening of Fragaria x ananassa fruits.

    PubMed

    Medina-Puche, Laura; Cumplido-Laso, Guadalupe; Amil-Ruiz, Francisco; Hoffmann, Thomas; Ring, Ludwig; Rodríguez-Franco, Antonio; Caballero, José Luis; Schwab, Wilfried; Muñoz-Blanco, Juan; Blanco-Portales, Rosario

    2014-02-01

    This work characterized the role of the R2R3-MYB10 transcription factor (TF) in strawberry fruit ripening. The expression of this TF takes place mainly in the fruit receptacle and is repressed by auxins and activated by abscisic acid (ABA), in parallel to the ripening process. Anthocyanin was not produced when FaMYB10 expression was transiently silenced in fruit receptacles. An increase in FaMYB10 expression was observed in water-stressed fruits, which was accompanied by an increase in both ABA and anthocyanin content. High-throughput transcriptomic analyses performed in fruits with downregulated FaMYB10 expression indicated that this TF regulates the expression of most of the Early-regulated Biosynthesis Genes (EBGs) and the Late-regulated Biosynthesis Genes (LBGs) genes involved in anthocyanin production in ripened fruit receptacles. Besides, the expression of FaMYB10 was not regulated by FaMYB1 and vice versa. Taken together, all these data clearly indicate that the Fragaria × ananassa MYB10 TF plays a general regulatory role in the flavonoid/phenylpropanoid pathway during the ripening of strawberry. PMID:24277278

  10. MYB10 plays a major role in the regulation of flavonoid/phenylpropanoid metabolism during ripening of Fragaria x ananassa fruits.

    PubMed

    Medina-Puche, Laura; Cumplido-Laso, Guadalupe; Amil-Ruiz, Francisco; Hoffmann, Thomas; Ring, Ludwig; Rodríguez-Franco, Antonio; Caballero, José Luis; Schwab, Wilfried; Muñoz-Blanco, Juan; Blanco-Portales, Rosario

    2014-02-01

    This work characterized the role of the R2R3-MYB10 transcription factor (TF) in strawberry fruit ripening. The expression of this TF takes place mainly in the fruit receptacle and is repressed by auxins and activated by abscisic acid (ABA), in parallel to the ripening process. Anthocyanin was not produced when FaMYB10 expression was transiently silenced in fruit receptacles. An increase in FaMYB10 expression was observed in water-stressed fruits, which was accompanied by an increase in both ABA and anthocyanin content. High-throughput transcriptomic analyses performed in fruits with downregulated FaMYB10 expression indicated that this TF regulates the expression of most of the Early-regulated Biosynthesis Genes (EBGs) and the Late-regulated Biosynthesis Genes (LBGs) genes involved in anthocyanin production in ripened fruit receptacles. Besides, the expression of FaMYB10 was not regulated by FaMYB1 and vice versa. Taken together, all these data clearly indicate that the Fragaria × ananassa MYB10 TF plays a general regulatory role in the flavonoid/phenylpropanoid pathway during the ripening of strawberry.

  11. MYB Promotes Desmoplasia in Pancreatic Cancer through Direct Transcriptional Up-regulation and Cooperative Action of Sonic Hedgehog and Adrenomedullin.

    PubMed

    Bhardwaj, Arun; Srivastava, Sanjeev K; Singh, Seema; Tyagi, Nikhil; Arora, Sumit; Carter, James E; Khushman, Moh'd; Singh, Ajay P

    2016-07-29

    Extensive desmoplasia is a prominent pathological characteristic of pancreatic cancer (PC) that not only impacts tumor development, but therapeutic outcome as well. Recently, we demonstrated a novel role of MYB, an oncogenic transcription factor, in PC growth and metastasis. Here we studied its effect on pancreatic tumor histopathology and associated molecular and biological mechanisms. Tumor-xenografts derived from orthotopic-inoculation of MYB-overexpressing PC cells exhibited far-greater desmoplasia in histological analyses compared with those derived from MYB-silenced PC cells. These findings were further confirmed by immunostaining of tumor-xenograft sections with collagen-I, fibronectin (major extracellular-matrix proteins), and α-SMA (well-characterized marker of myofibroblasts or activated pancreatic stellate cells (PSCs)). Likewise, MYB-overexpressing PC cells provided significantly greater growth benefit to PSCs in a co-culture system as compared with the MYB-silenced cells. Interrogation of deep-sequencing data from MYB-overexpressing versus -silenced PC cells identified Sonic-hedgehog (SHH) and Adrenomedullin (ADM) as two differentially-expressed genes among others, which encode for secretory ligands involved in tumor-stromal cross-talk. In-silico analyses predicted putative MYB-binding sites in SHH and ADM promoters, which was later confirmed by chromatin-immunoprecipitation. A cooperative role of SHH and ADM in growth promotion of PSCs was confirmed in co-culture by using their specific-inhibitors and exogenous recombinant-proteins. Importantly, while SHH acted exclusively in a paracrine fashion on PSCs and influenced the growth of PC cells only indirectly, ADM could directly impact the growth of both PC cells and PSCs. In summary, we identified MYB as novel regulator of pancreatic tumor desmoplasia, which is suggestive of its diverse roles in PC pathobiology. PMID:27246849

  12. The Transcription Factor VvMYB5b Contributes to the Regulation of Anthocyanin and Proanthocyanidin Biosynthesis in Developing Grape Berries12[W

    PubMed Central

    Deluc, Laurent; Bogs, Jochen; Walker, Amanda R.; Ferrier, Thilia; Decendit, Alain; Merillon, Jean-Michel; Robinson, Simon P.; Barrieu, François

    2008-01-01

    Among the dramatic changes occurring during grape berry (Vitis vinifera) development, those affecting the flavonoid pathway have provoked a number of investigations in the last 10 years. In addition to producing several compounds involved in the protection of the berry and the dissemination of the seeds, final products of this pathway also play a critical role in berry and wine quality. In this article, we describe the cloning and functional characterization of VvMYB5b, a cDNA isolated from a grape berry (V. vinifera ‘Cabernet Sauvignon’) library. VvMYB5b encodes a protein belonging to the R2R3-MYB family of transcription factors and displays significant similarity with VvMYB5a, another MYB factor recently shown to regulate flavonoid synthesis in grapevine. The ability of VvMYB5a and VvMYB5b to activate the grapevine promoters of several structural genes of the flavonoid pathway was confirmed by transient expression of the corresponding cDNAs in grape cells. Overexpression of VvMYB5b in tobacco (Nicotiana tabacum) leads to an up-regulation of genes encoding enzymes of the flavonoid pathway and results in the accumulation of anthocyanin- and proanthocyanidin-derived compounds. The ability of VvMYB5b to regulate particularly the anthocyanin and the proanthocyanidin pathways is discussed in relation to other recently characterized MYB transcription factors in grapevine. Taken together, data presented in this article give insight into the transcriptional mechanisms associated with the regulation of the flavonoid pathway throughout grape berry development. PMID:18539781

  13. Identification, cloning and characterization of R2R3-MYB gene family in canola (Brassica napus L.) identify a novel member modulating ROS accumulation and hypersensitive-like cell death

    PubMed Central

    Chen, Bisi; Niu, Fangfang; Liu, Wu-Zhen; Yang, Bo; Zhang, Jingxiao; Ma, Jieyu; Cheng, Hao; Han, Feng; Jiang, Yuan-Qing

    2016-01-01

    The R2R3-MYB proteins comprise one of the largest families of transcription factors in plants. Although genome-wide analysis of this family has been carried out in some plant species, little is known about R2R3-MYB genes in canola (Brassica napus L.). In this study, we have identified 76 R2R3-MYB genes in the canola genome through mining of expressed sequence tags (ESTs). The cDNA sequences of 44 MYB genes were successfully cloned. The transcriptional activities of BnaMYB proteins encoded by these genes were assayed in yeast. The subcellular localizations of representative R2R3-MYB proteins were investigated through GFP fusion. Besides, the transcript abundance level analysis during abiotic conditions and ABA treatment identified a group of R2R3-MYB genes that responded to one or more treatments. Furthermore, we identified a previously functionally unknown MYB gene-BnaMYB78, which modulates reactive oxygen species (ROS)-dependent cell death in Nicotiana benthamiana, through regulating the transcription of a few ROS- and defence-related genes. Taken together, this study has provided a solid foundation for understanding the roles and regulatory mechanism of canola R2R3-MYB genes. PMID:26800702

  14. Identification, cloning and characterization of R2R3-MYB gene family in canola (Brassica napus L.) identify a novel member modulating ROS accumulation and hypersensitive-like cell death.

    PubMed

    Chen, Bisi; Niu, Fangfang; Liu, Wu-Zhen; Yang, Bo; Zhang, Jingxiao; Ma, Jieyu; Cheng, Hao; Han, Feng; Jiang, Yuan-Qing

    2016-04-01

    The R2R3-MYB proteins comprise one of the largest families of transcription factors in plants. Although genome-wide analysis of this family has been carried out in some plant species, little is known about R2R3-MYB genes in canola (Brassica napus L.). In this study, we have identified 76 R2R3-MYB genes in the canola genome through mining of expressed sequence tags (ESTs). The cDNA sequences of 44 MYB genes were successfully cloned. The transcriptional activities of BnaMYB proteins encoded by these genes were assayed in yeast. The subcellular localizations of representative R2R3-MYB proteins were investigated through GFP fusion. Besides, the transcript abundance level analysis during abiotic conditions and ABA treatment identified a group of R2R3-MYB genes that responded to one or more treatments. Furthermore, we identified a previously functionally unknown MYB gene-BnaMYB78, which modulates reactive oxygen species (ROS)-dependent cell death in Nicotiana benthamiana, through regulating the transcription of a few ROS- and defence-related genes. Taken together, this study has provided a solid foundation for understanding the roles and regulatory mechanism of canola R2R3-MYB genes. PMID:26800702

  15. RNAi-directed post transcriptional gene silencing of an Arabidopsis Myb transgene in tobacco

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The AtMyb90 gene encodes the 'production of anthocyanin pigment 2' (PAP2) transcription factor of Arabidopsis thaliana and is able to induce a visible hyper-pigmented phenotype when expressed in tobacco. Based upon this phenotype, we have used the AtMyb90 gene as a reporter gene to examine RNAi-dire...

  16. Identification of 30 MYB transcription factor genes and analysis of their expression during abiotic stress in peanut (Arachis hypogaea L.).

    PubMed

    Chen, Na; Yang, Qingli; Pan, Lijuan; Chi, Xiaoyuan; Chen, Mingna; Hu, Dongqing; Yang, Zhen; Wang, Tong; Wang, Mian; Yu, Shanlin

    2014-01-01

    The MYB superfamily constitutes one of the most abundant groups of transcription factors and plays central roles in developmental processes and defense responses in plants. In the work described in this article, 30 unique peanut MYB genes that contained full-length cDNA sequences were isolated. The 30 genes were grouped into three categories: one R1R2R3-MYB, nine R2R3-MYBs and 20 MYB-related members. The sequence composition of the R2 and R3 repeats was conserved among the nine peanut R2R3-MYB proteins. Phylogenetic comparison of the members of this superfamily between peanut and Arabidopsis revealed that the putative functions of some peanut MYB proteins were clustered into the Arabidopsis functional groups. Expression analysis during abiotic stress identified a group of MYB genes that responded to at least one stress treatment. This is the first comprehensive study of the MYB gene family in peanut.

  17. Estrogen receptor-α recruits P-TEFb to overcome transcriptional pausing in intron 1 of the MYB gene

    PubMed Central

    Mitra, Partha; Pereira, Lloyd A.; Drabsch, Yvette; Ramsay, Robert G.; Gonda, Thomas J.

    2012-01-01

    The MYB proto-oncogene is expressed in most estrogen receptor-positive (ERα+) breast tumors and cell lines. Expression of MYB is controlled, in breast cancer and other cell types, by a transcriptional pausing mechanism involving an attenuation site located ∼1.7 kb downstream from the transcription start site. In breast cancer cells, ligand-bound ERα binds close to, and drives transcription beyond this attenuation site, allowing synthesis of complete transcripts. However, little is known, in general, about the factors involved in relieving transcriptional attenuation, or specifically how ERα coordinates such factors to promote transcriptional elongation. Using cyclin dependent kinase 9 (CDK9) inhibitors, reporter gene assays and measurements of total and intronic MYB transcription, we show that functionally active CDK9 is required for estrogen-dependent transcriptional elongation. We further show by ChIP and co-immunoprecipitation studies that the P-TEFb complex (CDK9/CyclinT1) is recruited to the attenuation region by ligand-bound ERα, resulting in increased RNA polymerase II Ser-2 phosphorylation. These data provide new insights into MYB regulation, and given the critical roles of MYB in tumorigenesis, suggest targeting MYB elongation as potential therapeutic strategy. PMID:22492511

  18. The cotton MYB108 forms a positive feedback regulation loop with CML11 and participates in the defense response against Verticillium dahliae infection

    PubMed Central

    Cheng, Huan-Qing; Han, Li-Bo; Yang, Chun-Lin; Wu, Xiao-Min; Zhong, Nai-Qin; Wu, Jia-He; Wang, Fu-Xin; Xia, Gui-Xian

    2016-01-01

    Accumulating evidence indicates that plant MYB transcription factors participate in defense against pathogen attack, but their regulatory targets and related signaling processes remain largely unknown. Here, we identified a defense-related MYB gene (GhMYB108) from upland cotton (Gossypium hirsutum) and characterized its functional mechanism. Expression of GhMYB108 in cotton plants was induced by Verticillium dahliae infection and responded to the application of defense signaling molecules, including salicylic acid, jasmonic acid, and ethylene. Knockdown of GhMYB108 expression led to increased susceptibility of cotton plants to V. dahliae, while ecotopic overexpression of GhMYB108 in Arabidopsis thaliana conferred enhanced tolerance to the pathogen. Further analysis demonstrated that GhMYB108 interacted with the calmodulin-like protein GhCML11, and the two proteins form a positive feedback loop to enhance the transcription of GhCML11 in a calcium-dependent manner. Verticillium dahliae infection stimulated Ca2+ influx into the cytosol in cotton root cells, but this response was disrupted in both GhCML11-silenced plants and GhMYB108-silenced plants in which expression of several calcium signaling-related genes was down-regulated. Taken together, these results indicate that GhMYB108 acts as a positive regulator in defense against V. dahliae infection by interacting with GhCML11. Furthermore, the data also revealed the important roles and synergetic regulation of MYB transcription factor, Ca2+, and calmodulin in plant immune responses. PMID:26873979

  19. C-myb Regulates Autophagy for Pulp Vitality in Glucose Oxidative Stress.

    PubMed

    Lee, Y H; Kim, H S; Kim, J S; Yu, M K; Cho, S D; Jeon, J G; Yi, H K

    2016-04-01

    Diabetes mellitus is closely related to oral-complicated diseases by oxidative stress. This study investigates whether cellular myeloblastosis (c-myb) could protect human dental pulp cells against glucose oxidative stress and regulate autophagy activity for pulp vitality. Diabetes mellitus was induced by streptozotocin in Sprague-Dawley rats, and their pulp tissue in teeth was analyzed in terms of pulp cavity and molecules by hematoxylin and eosin and immunohistochemistry staining. Human dental pulp cells were serially subcultured and treated with glucose oxidase in the presence of elevated glucose to generate glucose oxidative stress. The replication-deficient adenovirus c-myb and small interfering RNA c-myb were introduced for c-myb expression. The pulp tissue from the diabetic rats was structurally different from normal tissue in terms of narrow pulp capacity, reduced c-myb, and dentinogenesis molecules. Glucose oxidase treatment decreased c-myb and dentinogenesis molecules (bone morphogenetic protein 2 and 7, dentin matrix protein 1, and dentin sialophosphoprotein) in human dental pulp cells. However, overexpression of c-myb by adenovirus c-myb increased dentinogenesis, autophagy molecules (autophagy protein 5, microtubule-associated protein 1A/1B-light chain 3, and Beclin-1), and cell survival via p-AMPK/AKT signaling even with glucose oxidative stress. In contrast, the lack of c-myb decreased the above molecules and cell survival by downregulating p-AMPK/AKT signaling. The results indicate that diabetes leads to irreversible damage to dental pulp, which is related to downexpression of autophagy via the p-AMPK/AKT pathway by decline of c-myb. The findings of this study provide a new insight that c-myb could ameliorate autophagy activity and that it is applicable for monitoring complicated diseases of dental pulp. The involvement of c-myb in pulp pathology could serve a therapeutic target in oral-complicated diseases. PMID:26661713

  20. C-myb Regulates Autophagy for Pulp Vitality in Glucose Oxidative Stress.

    PubMed

    Lee, Y H; Kim, H S; Kim, J S; Yu, M K; Cho, S D; Jeon, J G; Yi, H K

    2016-04-01

    Diabetes mellitus is closely related to oral-complicated diseases by oxidative stress. This study investigates whether cellular myeloblastosis (c-myb) could protect human dental pulp cells against glucose oxidative stress and regulate autophagy activity for pulp vitality. Diabetes mellitus was induced by streptozotocin in Sprague-Dawley rats, and their pulp tissue in teeth was analyzed in terms of pulp cavity and molecules by hematoxylin and eosin and immunohistochemistry staining. Human dental pulp cells were serially subcultured and treated with glucose oxidase in the presence of elevated glucose to generate glucose oxidative stress. The replication-deficient adenovirus c-myb and small interfering RNA c-myb were introduced for c-myb expression. The pulp tissue from the diabetic rats was structurally different from normal tissue in terms of narrow pulp capacity, reduced c-myb, and dentinogenesis molecules. Glucose oxidase treatment decreased c-myb and dentinogenesis molecules (bone morphogenetic protein 2 and 7, dentin matrix protein 1, and dentin sialophosphoprotein) in human dental pulp cells. However, overexpression of c-myb by adenovirus c-myb increased dentinogenesis, autophagy molecules (autophagy protein 5, microtubule-associated protein 1A/1B-light chain 3, and Beclin-1), and cell survival via p-AMPK/AKT signaling even with glucose oxidative stress. In contrast, the lack of c-myb decreased the above molecules and cell survival by downregulating p-AMPK/AKT signaling. The results indicate that diabetes leads to irreversible damage to dental pulp, which is related to downexpression of autophagy via the p-AMPK/AKT pathway by decline of c-myb. The findings of this study provide a new insight that c-myb could ameliorate autophagy activity and that it is applicable for monitoring complicated diseases of dental pulp. The involvement of c-myb in pulp pathology could serve a therapeutic target in oral-complicated diseases.

  1. Expression and Anthocyanin Biosynthesis-Modulating Potential of Sweet Cherry (Prunus avium L.) MYB10 and bHLH Genes.

    PubMed

    Starkevič, Pavel; Paukštytė, Jurgita; Kazanavičiūtė, Vaiva; Denkovskienė, Erna; Stanys, Vidmantas; Bendokas, Vidmantas; Šikšnianas, Tadeušas; Ražanskienė, Aušra; Ražanskas, Raimundas

    2015-01-01

    Anthocyanins are essential contributors to fruit coloration, an important quality feature and a breed determining trait of a sweet cherry fruit. It is well established that the biosynthesis of anthocyanins is regulated by an interplay of specific transcription factors belonging to MYB and bHLH families accompanied by a WD40 protein. In this study, we isolated and analyzed PaWD40, PabHLH3, PabHLH33, and several closely related MYB10 gene variants from different cultivars of sweet cherry, analyzed their expression in fruits with different anthocyanin levels at several developmental stages, and determined their capabilities to modulate anthocyanin synthesis in leaves of two Nicotiana species. Our results indicate that transcription level of variant PaMYB10.1-1 correlates with fruit coloration, but anthocyanin synthesis in Nicotiana was induced by another variant, PaMYB10.1-3, which is moderately expressed in fruits. The analysis of two fruit-expressed bHLH genes revealed that PabHLH3 enhances MYB-induced anthocyanin synthesis, whereas PabHLH33 has strong inhibitory properties. PMID:25978735

  2. Expression and Anthocyanin Biosynthesis-Modulating Potential of Sweet Cherry (Prunus avium L.) MYB10 and bHLH Genes

    PubMed Central

    Starkevič, Pavel; Paukštytė, Jurgita; Kazanavičiūtė, Vaiva; Denkovskienė, Erna; Stanys, Vidmantas; Bendokas, Vidmantas; Šikšnianas, Tadeušas; Ražanskienė, Aušra; Ražanskas, Raimundas

    2015-01-01

    Anthocyanins are essential contributors to fruit coloration, an important quality feature and a breed determining trait of a sweet cherry fruit. It is well established that the biosynthesis of anthocyanins is regulated by an interplay of specific transcription factors belonging to MYB and bHLH families accompanied by a WD40 protein. In this study, we isolated and analyzed PaWD40, PabHLH3, PabHLH33, and several closely related MYB10 gene variants from different cultivars of sweet cherry, analyzed their expression in fruits with different anthocyanin levels at several developmental stages, and determined their capabilities to modulate anthocyanin synthesis in leaves of two Nicotiana species. Our results indicate that transcription level of variant PaMYB10.1-1 correlates with fruit coloration, but anthocyanin synthesis in Nicotiana was induced by another variant, PaMYB10.1-3, which is moderately expressed in fruits. The analysis of two fruit-expressed bHLH genes revealed that PabHLH3 enhances MYB-induced anthocyanin synthesis, whereas PabHLH33 has strong inhibitory properties. PMID:25978735

  3. Arabidopsis TRANSPARENT TESTA GLABRA2 is directly regulated by R2R3 MYB transcription factors and is involved in regulation of GLABRA2 transcription in epidermal differentiation.

    PubMed

    Ishida, Tetsuya; Hattori, Sayoko; Sano, Ryosuke; Inoue, Kayoko; Shirano, Yumiko; Hayashi, Hiroaki; Shibata, Daisuke; Sato, Shusei; Kato, Tomohiko; Tabata, Satoshi; Okada, Kiyotaka; Wada, Takuji

    2007-08-01

    Arabidopsis thaliana TRANSPARENT TESTA GLABRA2 (TTG2) encodes a WRKY transcription factor and is expressed in young leaves, trichomes, seed coats, and root hairless cells. An examination of several trichome and root hair mutants indicates that MYB and bHLH genes regulate TTG2 expression. Two MYB binding sites in the TTG2 5' regulatory region act as cis regulatory elements and as direct targets of R2R3 MYB transcription factors such as WEREWOLF, GLABRA1, and TRANSPARENT TESTA2. Mutations in TTG2 cause phenotypic defects in trichome development and seed color pigmentation. Transgenic plants expressing a chimeric repressor version of the TTG2 protein (TTG2:SRDX) showed defects in trichome formation, anthocyanin accumulation, seed color pigmentation, and differentiation of root hairless cells. GLABRA2 (GL2) expression was markedly reduced in roots of ProTTG2:TTG2:SRDX transgenic plants, suggesting that TTG2 is involved in the regulation of GL2 expression, although GL2 expression in the ttg2 mutant was similar to that in the wild type. Our analysis suggests a new step in a regulatory cascade of epidermal differentiation, in which complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, which then regulates GL2 expression with complexes containing R2R3 MYB and bHLH in the differentiation of trichomes and root hairless cells.

  4. The Arabidopsis Transcription Factor MYB112 Promotes Anthocyanin Formation during Salinity and under High Light Stress1[OPEN

    PubMed Central

    Lotkowska, Magda E.; Tohge, Takayuki; Fernie, Alisdair R.; Xue, Gang-Ping; Balazadeh, Salma; Mueller-Roeber, Bernd

    2015-01-01

    MYB transcription factors (TFs) are important regulators of flavonoid biosynthesis in plants. Here, we report MYB112 as a formerly unknown regulator of anthocyanin accumulation in Arabidopsis (Arabidopsis thaliana). Expression profiling after chemically induced overexpression of MYB112 identified 28 up- and 28 down-regulated genes 5 h after inducer treatment, including MYB7 and MYB32, which are both induced. In addition, upon extended induction, MYB112 also positively affects the expression of PRODUCTION OF ANTHOCYANIN PIGMENT1, a key TF of anthocyanin biosynthesis, but acts negatively toward MYB12 and MYB111, which both control flavonol biosynthesis. MYB112 binds to an 8-bp DNA fragment containing the core sequence (A/T/G)(A/C)CC(A/T)(A/G/T)(A/C)(T/C). By electrophoretic mobility shift assay and chromatin immunoprecipitation coupled to quantitative polymerase chain reaction, we show that MYB112 binds in vitro and in vivo to MYB7 and MYB32 promoters, revealing them as direct downstream target genes. We further show that MYB112 expression is up-regulated by salinity and high light stress, environmental parameters that both require the MYB112 TF for anthocyanin accumulation under these stresses. In contrast to several other MYB TFs affecting anthocyanin biosynthesis, MYB112 expression is not controlled by nitrogen limitation or an excess of carbon. Thus, MYB112 constitutes a regulator that promotes anthocyanin accumulation under abiotic stress conditions. PMID:26378103

  5. tom-1, a novel v-Myb target gene expressed in AMV- and E26-transformed myelomonocytic cells.

    PubMed Central

    Burk, O; Worpenberg, S; Haenig, B; Klempnauer, K H

    1997-01-01

    The retroviral oncogene v-myb is a mutated and truncated version of the c-myb proto-oncogene and encodes a transcription factor (v-Myb) that specifically transforms myelomonocytic cells. Two different variants of v-myb, transduced independently by the oncogenic chicken retroviruses AMV and E26, have been characterized. It is believed that both variants of v-Myb transform myelomonocytic cells by affecting the expression of specific genes; however, no target genes common to both oncogenic viruses have been identified. Here, we describe the identification of a novel v-Myb target gene, designated as tom-1 (target of myb 1). The tom-1 gene has two promoters, one of which is Myb-inducible. tom-1 is expressed at elevated levels in AMV-transformed as well as in E26-transformed myeloid cells. We show that tom-1 activation by v-Myb does not require de novo protein synthesis and that the Myb-inducible tom-1 promoter contains a functional Myb binding site. Thus, tom-1 is the first example of a direct target gene for both oncogenic forms of the v-myb gene. Further analysis of the Myb-inducible tom-1 promoter shows that a C/EBP binding site is juxtaposed to the Myb binding site and that C/EBP is required for the Myb-dependent activation of the promoter. Together with previous work our results suggest that C/EBP may be a general cooperation partner for v-Myb in myelomonocytic cells. PMID:9135152

  6. Targeted silencing of BjMYB28 transcription factor gene directs development of low glucosinolate lines in oilseed Brassica juncea.

    PubMed

    Augustine, Rehna; Mukhopadhyay, Arundhati; Bisht, Naveen C

    2013-09-01

    Brassica juncea (Indian mustard), a globally important oilseed crop, contains relatively high amount of seed glucosinolates ranging from 80 to 120 μmol/g dry weight (DW). One of the major breeding objectives in oilseed Brassicas is to improve the seed-meal quality through the development of low-seed-glucosinolate lines (<30 μmol/g DW), as high amounts of certain seed glucosinolates are known to be anti-nutritional and reduce the meal palatability. Here, we report the development of transgenic B. juncea lines having seed glucosinolates as low as 11.26 μmol/g DW, through RNAi-based targeted suppression of BjMYB28, a R2R3-MYB transcription factor family gene involved in aliphatic glucosinolate biosynthesis. Targeted silencing of BjMYB28 homologs provided significant reduction in the anti-nutritional aliphatic glucosinolates fractions, without altering the desirable nonaliphatic glucosinolate pool, both in leaves and seeds of transgenic plants. Molecular characterization of single-copy, low glucosinolate homozygous lines confirmed significant down-regulation of BjMYB28 homologs vis-à-vis enhanced accumulation of BjMYB28-specific siRNA pool. Consequently, these low glucosinolate lines also showed significant suppression of genes involved in aliphatic glucosinolate biosynthesis. The low glucosinolate trait was stable in subsequent generations of the transgenic lines with no visible off-target effects on plant growth and development. Various seed quality parameters including fatty acid composition, oil content, protein content and seed weight of the low glucosinolate lines also remained unaltered, when tested under containment conditions in the field. Our results indicate that targeted silencing of a key glucosinolate transcriptional regulator MYB28 has huge potential for reducing the glucosinolates content and improving the seed-meal quality of oilseed Brassica crops. PMID:23721233

  7. MYB10 and MYB72 are required for growth under iron-limiting conditions.

    PubMed

    Palmer, Christine M; Hindt, Maria N; Schmidt, Holger; Clemens, Stephan; Guerinot, Mary Lou

    2013-11-01

    Iron is essential for photosynthesis and is often a limiting nutrient for plant productivity. Plants respond to conditions of iron deficiency by increasing transcript abundance of key genes involved in iron homeostasis, but only a few regulators of these genes have been identified. Using genome-wide expression analysis, we searched for transcription factors that are induced within 24 hours after transferring plants to iron-deficient growth conditions. Out of nearly 100 transcription factors shown to be up-regulated, we identified MYB10 and MYB72 as the most highly induced transcription factors. Here, we show that MYB10 and MYB72 are functionally redundant and are required for plant survival in alkaline soil where iron availability is greatly restricted. myb10myb72 double mutants fail to induce transcript accumulation of the nicotianamine synthase gene NAS4. Both myb10myb72 mutants and nas4-1 mutants have reduced iron concentrations, chlorophyll levels, and shoot mass under iron-limiting conditions, indicating that these genes are essential for proper plant growth. The double myb10myb72 mutant also showed nickel and zinc sensitivity, similar to the nas4 mutant. Ectopic expression of NAS4 rescues myb10myb72 plants, suggesting that loss of NAS4 is the primary defect in these plants and emphasizes the importance of nicotianamine, an iron chelator, in iron homeostasis. Overall, our results provide evidence that MYB10 and MYB72 act early in the iron-deficiency regulatory cascade to drive gene expression of NAS4 and are essential for plant survival under iron deficiency. PMID:24278034

  8. AtMYB7, a new player in the regulation of UV-sunscreens in Arabidopsis thaliana.

    PubMed

    Fornalé, Silvia; Lopez, Eric; Salazar-Henao, Jorge E; Fernández-Nohales, Pedro; Rigau, Joan; Caparros-Ruiz, David

    2014-03-01

    The phenylpropanoid metabolic pathway provides a wide variety of essential compounds for plants. Together with sinapate esters, in Brassicaceae species, flavonoids play an important role in protecting plants against UV irradiation. In this work we have characterized Arabidopsis thaliana AtMYB7, the closest homolog of AtMYB4 and AtMYB32, described as repressors of different branches of phenylpropanoid metabolism. The characterization of atmyb7 plants revealed an induction of several genes involved in flavonol biosynthesis and an increased amount of these compounds. In addition, AtMYB7 gene expression is repressed by AtMYB4. As a consequence, the atmyb4 mutant plants present a reduction of flavonol contents, indicating once more that AtMYB7 represses flavonol biosynthesis. Our results also show that AtMYB7 gene expression is induced by salt stress. Induction assays indicated that AtMYB7 represses several genes of the flavonoid pathway, DFR and UGT being early targets of this transcription factor. The results obtained indicate that AtMYB7 is a repressor of flavonol biosynthesis and also led us to propose AtMYB4 and AtMYB7 as part of the regulatory mechanism controlling the balance of the main A. thaliana UV-sunscreens. PMID:24319076

  9. Expression of a wheat MYB gene in transgenic tobacco enhances resistance to Ralstonia solanacearum, and to drought and salt stresses.

    PubMed

    Liu, Hongxia; Zhou, Xianyao; Dong, Na; Liu, Xin; Zhang, Huaiyu; Zhang, Zengyan

    2011-09-01

    MYB transcription factors play diverse roles in plant growth, developmental processes and stress responses. A full-length cDNA sequence of a MYB gene, namely TaPIMP1, was isolated from wheat (Triticum aestivum L.). The TaPIMP1 transcript level was significantly up-regulated by inoculation with a fungal pathogen Bipolaris sorokiniana and by drought treatment. TaPIMP1 encodes the MYB protein TaPIMP1 consisting of 323 amino acids. TaPIMP1 contains two MYB DNA binding domains (R2, R3), two putative nuclear localization sites and two putative transcription activation domains. TaPIMP1 is a new member of the R2R3-MYB transcription factor subfamily. Transient expression in onion epidermal cells of GFP fused with TaPIMP1 proved that subcellular localization of TaPIMP1 occurred in the nucleus. The TaPIMP1 gene was transferred into tobacco (Nicotiana tabacum L.) cultivar W38 by Agrobacterium-mediated transformation. After screening through PCR and RT-PCR analyses, transgenic tobacco lines expressing TaPIMP1 were identified and evaluated for pathogen resistance, and drought and salt tolerance. Compared to untransformed tobacco host plants, TaPIMP1 expressing plants displayed significantly enhanced resistance to Ralstonia solanacearum and exhibited improved tolerances to drought and salt stresses. In these transgenic lines, the activities of phenylalanine ammonia-lyase (PAL) and superoxide dismutase (SOD) were significantly increased relative to wild-type tobacco plants. The results suggested that the wheat R2R3-MYB transcription factor plays an important role in modulating responses to biotic and abiotic stresses.

  10. Expression of a wheat MYB gene in transgenic tobacco enhances resistance to Ralstonia solanacearum, and to drought and salt stresses.

    PubMed

    Liu, Hongxia; Zhou, Xianyao; Dong, Na; Liu, Xin; Zhang, Huaiyu; Zhang, Zengyan

    2011-09-01

    MYB transcription factors play diverse roles in plant growth, developmental processes and stress responses. A full-length cDNA sequence of a MYB gene, namely TaPIMP1, was isolated from wheat (Triticum aestivum L.). The TaPIMP1 transcript level was significantly up-regulated by inoculation with a fungal pathogen Bipolaris sorokiniana and by drought treatment. TaPIMP1 encodes the MYB protein TaPIMP1 consisting of 323 amino acids. TaPIMP1 contains two MYB DNA binding domains (R2, R3), two putative nuclear localization sites and two putative transcription activation domains. TaPIMP1 is a new member of the R2R3-MYB transcription factor subfamily. Transient expression in onion epidermal cells of GFP fused with TaPIMP1 proved that subcellular localization of TaPIMP1 occurred in the nucleus. The TaPIMP1 gene was transferred into tobacco (Nicotiana tabacum L.) cultivar W38 by Agrobacterium-mediated transformation. After screening through PCR and RT-PCR analyses, transgenic tobacco lines expressing TaPIMP1 were identified and evaluated for pathogen resistance, and drought and salt tolerance. Compared to untransformed tobacco host plants, TaPIMP1 expressing plants displayed significantly enhanced resistance to Ralstonia solanacearum and exhibited improved tolerances to drought and salt stresses. In these transgenic lines, the activities of phenylalanine ammonia-lyase (PAL) and superoxide dismutase (SOD) were significantly increased relative to wild-type tobacco plants. The results suggested that the wheat R2R3-MYB transcription factor plays an important role in modulating responses to biotic and abiotic stresses. PMID:21597961

  11. Genome-Wide Identification of R2R3-MYB Genes and Expression Analyses During Abiotic Stress in Gossypium raimondii

    PubMed Central

    He, Qiuling; Jones, Don C.; Li, Wei; Xie, Fuliang; Ma, Jun; Sun, Runrun; Wang, Qinglian; Zhu, Shuijin; Zhang, Baohong

    2016-01-01

    The R2R3-MYB is one of the largest families of transcription factors, which have been implicated in multiple biological processes. There is great diversity in the number of R2R3-MYB genes in different plants. However, there is no report on genome-wide characterization of this gene family in cotton. In the present study, a total of 205 putative R2R3-MYB genes were identified in cotton D genome (Gossypium raimondii), that are much larger than that found in other cash crops with fully sequenced genomes. These GrMYBs were classified into 13 groups with the R2R3-MYB genes from Arabidopsis and rice. The amino acid motifs and phylogenetic tree were predicted and analyzed. The sequences of GrMYBs were distributed across 13 chromosomes at various densities. The results showed that the expansion of the G. Raimondii R2R3-MYB family was mainly attributable to whole genome duplication and segmental duplication. Moreover, the expression pattern of 52 selected GrMYBs and 46 GaMYBs were tested in roots and leaves under different abiotic stress conditions. The results revealed that the MYB genes in cotton were differentially expressed under salt and drought stress treatment. Our results will be useful for determining the precise role of the MYB genes during stress responses with crop improvement. PMID:27009386

  12. Expression of SANT/HTH Myb mRNA, a plant morphogenesis-regulating transcription factor, changes due to viroid infection.

    PubMed

    Matoušek, Jaroslav; Piernikarczyk, Rajen J J; Týcová, Anna; Duraisamy, Ganesh S; Kocábek, Tomáš; Steger, Gerhard

    2015-07-01

    Potato spindle tuber viroid (PSTVd) belongs to plant-pathogenic, circular, non-coding RNAs. Its propagation is accompanied by (mis)regulation of host genes and induction of pathogenesis symptoms including changes of leaf morphogenesis depending on the strength of viroid variant. We found strong genotype-dependent suppression of tomato morphogenesis-regulating transcription factor SANT/HTH-Myb (SlMyb) due to viroid pathogenesis. Its relative mRNA level was found to be significantly decreased in PSTVd-sensitive tomato (cvs Rutgers and Heinz 1706) due to degradation processes, but increased in PSTVd-tolerant (cv. Harzfeuer). In heterologous system of Nicotiana benthamiana, we observed a SlMyb-associated necrotic effect in agroinfiltrated leaf sectors during ectopic overexpression. Leaf sector necroses were accompanied by activation of nucleolytic enzymes but were suppressed by a strongly pathogenic PSTVd variant. Contrary to that, PSTVd's effect was inhibited by the silencing suppressor p19. It was found that in both, Solanum lycopersicum leaves and N. benthamiana leaf sectors, SlMyb mRNA degradation was significantly stronger in viroid-infected tissues. Necroses induction as well as gene silencing experiments using the SANT/HTH-Myb homologues revealed involvement of this Myb in physiological changes like distortions in flower morphogenesis and growth suppression. PMID:26118459

  13. An R2R3-MYB Transcription Factor Regulates Eugenol Production in Ripe Strawberry Fruit Receptacles1

    PubMed Central

    Medina-Puche, Laura; Molina-Hidalgo, Francisco Javier; Boersma, Maaike; Schuurink, Robert C.; López-Vidriero, Irene; Solano, Roberto; Franco-Zorrilla, José-Manuel; Caballero, José Luis; Blanco-Portales, Rosario; Muñoz-Blanco, Juan

    2015-01-01

    Eugenol is a volatile phenylpropanoid that contributes to flower and ripe fruit scent. In ripe strawberry (Fragaria × ananassa) fruit receptacles, eugenol is biosynthesized by eugenol synthase (FaEGS2). However, the transcriptional regulation of this process is still unknown. We have identified and functionally characterized an R2R3 MYB transcription factor (EMISSION OF BENZENOID II [FaEOBII]) that seems to be the orthologous gene of PhEOBII from Petunia hybrida, which contributes to the regulation of eugenol biosynthesis in petals. The expression of FaEOBII was ripening related and fruit receptacle specific, although high expression values were also found in petals. This expression pattern of FaEOBII correlated with eugenol content in both fruit receptacle and petals. The expression of FaEOBII was repressed by auxins and activated by abscisic acid, in parallel to the ripening process. In ripe strawberry receptacles, where the expression of FaEOBII was silenced, the expression of CINNAMYL ALCOHOL DEHYDROGENASE1 and FaEGS2, two structural genes involved in eugenol production, was down-regulated. A subsequent decrease in eugenol content in ripe receptacles was also observed, confirming the involvement of FaEOBII in eugenol metabolism. Additionally, the expression of FaEOBII was under the control of FaMYB10, another R2R3 MYB transcription factor that regulates the early and late biosynthetic genes from the flavonoid/phenylpropanoid pathway. In parallel, the amount of eugenol in FaMYB10-silenced receptacles was also diminished. Taken together, these data indicate that FaEOBII plays a regulating role in the volatile phenylpropanoid pathway gene expression that gives rise to eugenol production in ripe strawberry receptacles. PMID:25931522

  14. MdMYB1 Regulates Anthocyanin and Malate Accumulation by Directly Facilitating Their Transport into Vacuoles in Apples1[OPEN

    PubMed Central

    Hu, Da-Gang; Sun, Cui-Hui; Ma, Qi-Jun; You, Chun-Xiang; Hao, Yu-Jin

    2016-01-01

    Tonoplast transporters, including proton pumps and secondary transporters, are essential for plant cell function and for quality formation of fleshy fruits and ornamentals. Vacuolar transport of anthocyanins, malate, and other metabolites is directly or indirectly dependent on the H+-pumping activities of vacuolar H+-ATPase (VHA) and/or vacuolar H+-pyrophosphatase, but how these proton pumps are regulated in modulating vacuolar transport is largely unknown. Here, we report a transcription factor, MdMYB1, in apples that binds to the promoters of two genes encoding the B subunits of VHA, MdVHA-B1 and MdVHA-B2, to transcriptionally activate its expression, thereby enhancing VHA activity. A series of transgenic analyses in apples demonstrates that MdMYB1/10 controls cell pH and anthocyanin accumulation partially by regulating MdVHA-B1 and MdVHA-B2. Furthermore, several other direct target genes of MdMYB10 are identified, including MdVHA-E2, MdVHP1, MdMATE-LIKE1, and MdtDT, which are involved in H+-pumping or in the transport of anthocyanins and malates into vacuoles. Finally, we show that the mechanism by which MYB controls malate and anthocyanin accumulation in apples also operates in Arabidopsis (Arabidopsis thaliana). These findings provide novel insights into how MYB transcription factors directly modulate the vacuolar transport system in addition to anthocyanin biosynthesis, consequently controlling organ coloration and cell pH in plants. PMID:26637549

  15. MdMYB1 Regulates Anthocyanin and Malate Accumulation by Directly Facilitating Their Transport into Vacuoles in Apples.

    PubMed

    Hu, Da-Gang; Sun, Cui-Hui; Ma, Qi-Jun; You, Chun-Xiang; Cheng, Lailiang; Hao, Yu-Jin

    2016-03-01

    Tonoplast transporters, including proton pumps and secondary transporters, are essential for plant cell function and for quality formation of fleshy fruits and ornamentals. Vacuolar transport of anthocyanins, malate, and other metabolites is directly or indirectly dependent on the H(+)-pumping activities of vacuolar H(+)-ATPase (VHA) and/or vacuolar H(+)-pyrophosphatase, but how these proton pumps are regulated in modulating vacuolar transport is largely unknown. Here, we report a transcription factor, MdMYB1, in apples that binds to the promoters of two genes encoding the B subunits of VHA, MdVHA-B1 and MdVHA-B2, to transcriptionally activate its expression, thereby enhancing VHA activity. A series of transgenic analyses in apples demonstrates that MdMYB1/10 controls cell pH and anthocyanin accumulation partially by regulating MdVHA-B1 and MdVHA-B2. Furthermore, several other direct target genes of MdMYB10 are identified, including MdVHA-E2, MdVHP1, MdMATE-LIKE1, and MdtDT, which are involved in H(+)-pumping or in the transport of anthocyanins and malates into vacuoles. Finally, we show that the mechanism by which MYB controls malate and anthocyanin accumulation in apples also operates in Arabidopsis (Arabidopsis thaliana). These findings provide novel insights into how MYB transcription factors directly modulate the vacuolar transport system in addition to anthocyanin biosynthesis, consequently controlling organ coloration and cell pH in plants. PMID:26637549

  16. [Cloning and functional analysis of Phyllostachys edulis MYB transcription factor PeMYB2].

    PubMed

    Xiao, Dong-Chang; Zhang, Zhi-Jun; Xu, Ying-Wu; Yang, Li; Zhang, Feng-Xue; Wang, Chao-Li

    2013-10-01

    MYB-type transcription factor is one of the largest families in plants, which plays important roles in accepting stress signals from environment and regulating the expression of stress-tolerant genes. In this paper, using homologous cloning and RACE technology, a MYB-type transcription factor, designated PeMYB2, was cloned from Phyllostachys edulis. The results of bioinformatics showed that PeMYB2 is a typical R2R3-MYB. It contained two tandem repeats in its N-terminus, and a membrane protein DUF3651 in its C-terminus. In addition, phylogenetic analysis indicated that PeMYB2 shared the highest homology with 85.98% to OsMYB18 protein from Oryza sativa spp. Japonica. In addition, a yeast one-hybrid assay showed that PeMYB2 could activate the expression of downstream genes. After PeMYB2 was transformed into Arabidopsis thaliana, seven PeMYB2 transgenic Arabidopsis lines were obtained. Phenotypic analysis of the transgenic and wild-type Arabidopsis showed that over-expression of PeMYB2 caused delayed flower or dwarfism in transgenic Arabidopsis. Under the abiotic stress conditions, such as salt and cold stresses, the over-expression of PeMYB2 in Arabidopsis had higher survival rate than the wild-type Arabidopsis. Expression analysis of saline stress response marker genes in the transgenic and wild-type plants under the salt stress condition showed that PeMYB2 regulated the expression of NXH1, SOS1, RD29A, and COR15A. As the result, PeMYB2 might play an important role in various responses to abiotic stresses in P. edulis.

  17. WEREWOLF, a MYB-related protein in Arabidopsis, is a position-dependent regulator of epidermal cell patterning.

    PubMed

    Lee, M M; Schiefelbein, J

    1999-11-24

    The formation of the root epidermis of Arabidopsis provides a simple and elegant model for the analysis of cell patterning. A novel gene, WEREWOLF (WER), is described here that is required for position-dependent patterning of the epidermal cell types. The WER gene encodes a MYB-type protein and is preferentially expressed within cells destined to adopt the non-hair fate. Furthermore, WER is shown to regulate the position-dependent expression of the GLABRA2 homeobox gene, to interact with a bHLH protein, and to act in opposition to the CAPRICE MYB. These results suggest a simple model to explain the specification of the two root epidermal cell types, and they provide insight into the molecular mechanisms used to control cell patterning.

  18. A Small Family of MYB-Regulatory Genes Controls Floral Pigmentation Intensity and Patterning in the Genus Antirrhinum[W

    PubMed Central

    Schwinn, Kathy; Venail, Julien; Shang, Yongjin; Mackay, Steve; Alm, Vibeke; Butelli, Eugenio; Oyama, Ryan; Bailey, Paul; Davies, Kevin; Martin, Cathie

    2006-01-01

    The Rosea1, Rosea2, and Venosa genes encode MYB-related transcription factors active in the flowers of Antirrhinum majus. Analysis of mutant phenotypes shows that these genes control the intensity and pattern of magenta anthocyanin pigmentation in flowers. Despite the structural similarity of these regulatory proteins, they influence the expression of target genes encoding the enzymes of anthocyanin biosynthesis with different specificities. Consequently, they are not equivalent biochemically in their activities. Different species of the genus Antirrhinum, native to Spain and Portugal, show striking differences in their patterns and intensities of floral pigmentation. Differences in anthocyanin pigmentation between at least six species are attributable to variations in the activity of the Rosea and Venosa loci. Set in the context of our understanding of the regulation of anthocyanin production in other genera, the activity of MYB-related genes is probably a primary cause of natural variation in anthocyanin pigmentation in plants. PMID:16531495

  19. Large scale in silico identification of MYB family genes from wheat expressed sequence tags.

    PubMed

    Cai, Hongsheng; Tian, Shan; Dong, Hansong

    2012-10-01

    The MYB proteins constitute one of the largest transcription factor families in plants. Much research has been performed to determine their structures, functions, and evolution, especially in the model plants, Arabidopsis, and rice. However, this transcription factor family has been much less studied in wheat (Triticum aestivum), for which no genome sequence is yet available. Despite this, expressed sequence tags are an important resource that permits opportunities for large scale gene identification. In this study, a total of 218 sequences from wheat were identified and confirmed to be putative MYB proteins, including 1RMYB, R2R3-type MYB, 3RMYB, and 4RMYB types. A total of 36 R2R3-type MYB genes with complete open reading frames were obtained. The putative orthologs were assigned in rice and Arabidopsis based on the phylogenetic tree. Tissue-specific expression pattern analyses confirmed the predicted orthologs, and this meant that gene information could be inferred from the Arabidopsis genes. Moreover, the motifs flanking the MYB domain were analyzed using the MEME web server. The distribution of motifs among wheat MYB proteins was investigated and this facilitated subfamily classification.

  20. Dual DNA binding specificity of a petal epidermis-specific MYB transcription factor (MYB.Ph3) from Petunia hybrida.

    PubMed Central

    Solano, R; Nieto, C; Avila, J; Cañas, L; Diaz, I; Paz-Ares, J

    1995-01-01

    The MYB.Ph3 protein recognized two DNA sequences that resemble the two known types of MYB DNA binding site: consensus I (MBSI), aaaAaaC(G/C)-GTTA, and consensus II (MBSII), aaaAGTTAGTTA. Optimal MBSI was recognized by animal c-MYB and not by Am305 from Antirrhinum, whereas MBSII showed the reverse behaviour. Different constraints on MYB.Ph3 binding to the two classes of sequences were demonstrated. DNA binding studies with mutated MBSI and MBSII and hydroxyl radical footprinting analysis, pointed to the N-terminal MYB repeat (R2) as the most involved in determining the dual DNA binding specificity of MYB.Ph3 and supported the idea that binding to MBSI and MBSII does not involve alternative orientations of the two repeats of MYB.Ph3. Minimal promoters containing either MBSI and MBSII were activated to the same extent by MYB.Ph3 in yeast, indicating that both types of binding site can be functionally equivalent. MYB.Ph3 binding sites are present in the promoter of flavonoid biosynthetic genes, such as the Petunia chsJ gene, which was transcriptionally activated by MYB.Ph3 in tobacco protoplasts. MYB.Ph3 was immunolocalized in the epidermal cell layer of petals, where flavonoid biosynthetic genes are actively expressed. This strongly suggests a role for MYB.Ph3 in the regulation of flavonoid biosynthesis. Images PMID:7737128

  1. An R2R3-MYB transcription factor regulates carotenoid pigmentation in Mimulus lewisii flowers.

    PubMed

    Sagawa, Janelle M; Stanley, Lauren E; LaFountain, Amy M; Frank, Harry A; Liu, Chang; Yuan, Yao-Wu

    2016-02-01

    Carotenoids are yellow, orange, and red pigments that contribute to the beautiful colors and nutritive value of many flowers and fruits. The structural genes in the highly conserved carotenoid biosynthetic pathway have been well characterized in multiple plant systems, but little is known about the transcription factors that control the expression of these structural genes. By analyzing a chemically induced mutant of Mimulus lewisii through bulk segregant analysis and transgenic experiments, we have identified an R2R3-MYB, Reduced Carotenoid Pigmentation 1 (RCP1), as the first transcription factor that positively regulates carotenoid biosynthesis during flower development. Loss-of-function mutations in RCP1 lead to down-regulation of all carotenoid biosynthetic genes and reduced carotenoid content in M. lewisii flowers, a phenotype recapitulated by RNA interference in the wild-type background. Overexpression of this gene in the rcp1 mutant background restores carotenoid production and, unexpectedly, results in simultaneous decrease of anthocyanin production in some transgenic lines by down-regulating the expression of an activator of anthocyanin biosynthesis. Identification of transcriptional regulators of carotenoid biosynthesis provides the 'toolbox' genes for understanding the molecular basis of flower color diversification in nature and for potential enhancement of carotenoid production in crop plants via genetic engineering. PMID:26377817

  2. Genome-Wide Identification, Evolution and Functional Divergence of MYB Transcription Factors in Chinese White Pear (Pyrus bretschneideri).

    PubMed

    Li, Xiaolong; Xue, Cheng; Li, Jiaming; Qiao, Xin; Li, Leiting; Yu, Li'ang; Huang, Yuhua; Wu, Jun

    2016-04-01

    The MYB superfamily is large and functionally diverse in plants. To date, MYB family genes have not yet been identified in Chinese white pear (Pyrus bretschneideri), and their functions remain unclear. In this study, we identified 231 genes as candidate MYB genes and divided them into four subfamilies. The R2R3-MYB (PbrMYB) family shared an R2R3 domain with 104 amino acid residues, including five conserved tryptophan residues. The Pbr MYB family was divided into 37 functional subgroups including 33 subgroups which contained both MYB genes of Rosaceae plants and AtMYB genes, and four subgroups which included only Rosaceae MYB genes or AtMYB genes. PbrMYB genes with similar functions clustered into the same subgroup, indicating functional conservation. We also found that whole-genome duplication (WGD) and dispersed duplications played critical roles in the expansion of the MYB family. The 87 Pbr MYB duplicated gene pairs dated back to the two WGD events. Purifying selection was the primary force driving Pbr MYB gene evolution. The 15 gene pairs presented 1-7 codon sites under positive selection. A total of 147 expressed genes were identified from RNA-sequencing data of fruit, and six Pbr MYB members in subgroup C1 were identified as important candidate genes in the regulation of lignin synthesis by quantitative real-time PCR analysis. Further correlation analysis revealed that six PbrMYBs were significantly correlated with five structural gene families (F5H, HCT, CCR, POD and C3'H) in the lignin pathway. The phylogenetic, evolution and expression analyses of the MYB gene family in Chinese white pear establish a solid foundation for future comprehensive functional analysis of Pbr MYB genes.

  3. Evaluation of MYB Promoter Methylation in Salivary Adenoid Cystic Carcinoma

    PubMed Central

    Shao, Chunbo; Bai, Weiliang; Junn, Jacqueline C.; Uemura, Mamoru; Hennessey, Patrick T.; Zaboli, David; Sidransky, David; Califano, Joseph A.; Ha, Patrick K.

    2011-01-01

    Summary The transcription factor MYB was recently proposed to be a promising oncogene candidate in salivary gland adenoid cystic carcinoma (ACC). However, the up-regulation of MYB in ACC could not be explained solely by deletion of its 3′ end. It is widely accepted that the promoter methylation status can regulate the transcription of genes, especially in human cancers. Therefore, it is important to know whether MYB promoter demethylation could explain the over-expression of MYB in ACC. By using the Methprimer program, we identified nine CpG islands in the promoter of MYB. All of these CpG islands were located within the −864 to +2,082 nt region relative to the transcription start site of MYB. We then used bisulfite genomic sequencing to evaluate the methylation levels of the CpG islands of MYB in 18 primary ACC tumors, 13 normal salivary gland tissues and nine cancer cell lines. Using cell lines, we also determined the relative MYB expression levels and correlated these with the methylation levels. With bisulfite genomic sequencing, we found no detectable methylation in the CpG islands of MYB in either ACC or normal salivary gland tissues. There was a variable degree of MYB expression in the cell lines tested, but none of these cell lines demonstrated promoter methylation. Promoter hypomethylation does not appear to explain the differential expression of MYB in ACC. An alternative mechanism needs to be proposed for the transcriptional control of MYB in ACC. PMID:21324728

  4. Functional analysis of the epidermal-specific MYB genes CAPRICE and WEREWOLF in Arabidopsis.

    PubMed

    Tominaga, Rumi; Iwata, Mineko; Okada, Kiyotaka; Wada, Takuji

    2007-07-01

    Epidermis cell differentiation in Arabidopsis thaliana is a model system for understanding the developmental end state of plant cells. Two types of MYB transcription factors, R2R3-MYB and R3-MYB, are involved in cell fate determination. To examine the molecular basis of this process, we analyzed the functional relationship of the R2R3-type MYB gene WEREWOLF (WER) and the R3-type MYB gene CAPRICE (CPC). Chimeric constructs made from the R3 MYB regions of WER and CPC used in reciprocal complementation experiments showed that the CPC R3 region cannot functionally substitute for the WER R3 region in the differentiation of hairless cells. However, WER R3 can substantially substitute for CPC R3. There are no differences in yeast interaction assays of WER or WER chimera proteins with GLABRA3 (GL3) or ENHANCER OF GLABRA3 (EGL3). CPC and CPC chimera proteins also have similar activity in preventing GL3 WER and EGL3 WER interactions. Furthermore, we showed by gel mobility shift assays that WER chimera proteins do not bind to the GL2 promoter region. However, a CPC chimera protein, which harbors the WER R3 motif, still binds to the GL2 promoter region.

  5. EjODO1, a MYB Transcription Factor, Regulating Lignin Biosynthesis in Developing Loquat (Eriobotrya japonica) Fruit

    PubMed Central

    Zhang, Jing; Ge, Hang; Zang, Chen; Li, Xian; Grierson, Donald; Chen, Kun-song; Yin, Xue-ren

    2016-01-01

    Lignin is important for plant secondary cell wall formation and participates in resistance to various biotic and abiotic stresses. Loquat undergoes lignification not only in vegetative tissues but also in flesh of postharvest fruit, which adversely affects consumer acceptance. Thus, researches on lignin biosynthesis and regulation are important to understand loquat fruit lignification. In loquat, a gene encoding an enzyme in the lignin biosynthesis pathway, Ej4CL1, was reported to be regulated by transcription factors, including EjMYB1, EjMYB2, EjMYB8, and EjAP2-1, knowledge of this process is still limited. With the aim of identifying novel transcriptional factors controlling lignin biosynthesis in loquat, the promoter of Ej4CL1 was utilized to screen a cDNA library by yeast one hybrid assay. A novel R2R3 MYB, named EjODO1, was identified. Real-time PCR analyses indicated that EjODO1 is highly expressed in lignified stems and roots. During fruit development, expression of EjODO1 decreased along with the reduction of lignin content and became undetectable in mature ripe fruit. Thus, EjODO1 is likely to be involved in lignification of vegetative organs and early fruit development but not in mature fruit or postharvest lignification. Dual-luciferase assay indicated that EjODO1 could trans-activate promoters of lignin biosynthesis genes, such as EjPAL1, Ej4CL1, and Ej4CL5 and transient overexpression of EjODO1 triggered lignin biosynthesis. These results indicate a role for EjODO1 in regulating lignin biosynthesis in loquat which is different from the previously characterized transcription factors. PMID:27695460

  6. EjODO1, a MYB Transcription Factor, Regulating Lignin Biosynthesis in Developing Loquat (Eriobotrya japonica) Fruit

    PubMed Central

    Zhang, Jing; Ge, Hang; Zang, Chen; Li, Xian; Grierson, Donald; Chen, Kun-song; Yin, Xue-ren

    2016-01-01

    Lignin is important for plant secondary cell wall formation and participates in resistance to various biotic and abiotic stresses. Loquat undergoes lignification not only in vegetative tissues but also in flesh of postharvest fruit, which adversely affects consumer acceptance. Thus, researches on lignin biosynthesis and regulation are important to understand loquat fruit lignification. In loquat, a gene encoding an enzyme in the lignin biosynthesis pathway, Ej4CL1, was reported to be regulated by transcription factors, including EjMYB1, EjMYB2, EjMYB8, and EjAP2-1, knowledge of this process is still limited. With the aim of identifying novel transcriptional factors controlling lignin biosynthesis in loquat, the promoter of Ej4CL1 was utilized to screen a cDNA library by yeast one hybrid assay. A novel R2R3 MYB, named EjODO1, was identified. Real-time PCR analyses indicated that EjODO1 is highly expressed in lignified stems and roots. During fruit development, expression of EjODO1 decreased along with the reduction of lignin content and became undetectable in mature ripe fruit. Thus, EjODO1 is likely to be involved in lignification of vegetative organs and early fruit development but not in mature fruit or postharvest lignification. Dual-luciferase assay indicated that EjODO1 could trans-activate promoters of lignin biosynthesis genes, such as EjPAL1, Ej4CL1, and Ej4CL5 and transient overexpression of EjODO1 triggered lignin biosynthesis. These results indicate a role for EjODO1 in regulating lignin biosynthesis in loquat which is different from the previously characterized transcription factors.

  7. Gene Expression and Yeast Two-Hybrid Studies of 1R-MYB Transcription Factor Mediating Drought Stress Response in Chickpea (Cicer arietinum L.)

    PubMed Central

    Ramalingam, Abirami; Kudapa, Himabindu; Pazhamala, Lekha T.; Garg, Vanika; Varshney, Rajeev K.

    2015-01-01

    Drought stress has been one of the serious constraints affecting chickpea productivity to a great extent. Genomics-assisted breeding has a potential to accelerate breeding precisely and efficiently. In order to do so, understanding the molecular mechanisms for drought tolerance and identification of candidate genes are crucial. Transcription factors (TFs) have important roles in the regulation of plant stress related genes. In this context, quantitative real time-PCR (qRT-PCR) was used to study the differential gene expression of selected TFs, identified from large-scale expressed sequence tags (ESTs) analysis, in contrasting drought responsive genotypes. Root tissues of ICC 4958 (tolerant), ICC 1882 (sensitive), JG 11 (elite), and JG 11+ (introgression line) were used for the study. Subsequently, a candidate single repeat MYB (1R-MYB) transcript that was remarkably induced in the drought tolerant genotypes under drought stress was cloned (coding sequence region for the 1R-MYB protein) and subjected to yeast two-hybrid (Y2H) analysis. The screening of a root cDNA library with Y2H using the 1R-MYB bait protein, identified three CDS encoding peptides namely, galactinol-sucrose galactosyltransferase 2, CBL (Calcineurin B-like)-interacting serine/threonine-protein kinase 25, and ABA responsive 17-like, which were confirmed by co-transformation in yeast. These findings provide preliminary insights into the ability of this 1R-MYB transcription factor to co-regulate drought tolerance mechanism in chickpea. PMID:26734027

  8. c-Myb Binding Sites in Haematopoietic Chromatin Landscapes

    PubMed Central

    Bengtsen, Mads; Klepper, Kjetil; Gundersen, Sveinung; Cuervo, Ignacio; Drabløs, Finn; Hovig, Eivind; Sandve, Geir Kjetil; Gabrielsen, Odd Stokke; Eskeland, Ragnhild

    2015-01-01

    Strict control of tissue-specific gene expression plays a pivotal role during lineage commitment. The transcription factor c-Myb has an essential role in adult haematopoiesis and functions as an oncogene when rearranged in human cancers. Here we have exploited digital genomic footprinting analysis to obtain a global picture of c-Myb occupancy in the genome of six different haematopoietic cell-types. We have biologically validated several c-Myb footprints using c-Myb knockdown data, reporter assays and DamID analysis. We show that our predicted conserved c-Myb footprints are highly dependent on the haematopoietic cell type, but that there is a group of gene targets common to all cell-types analysed. Furthermore, we find that c-Myb footprints co-localise with active histone mark H3K4me3 and are significantly enriched at exons. We analysed co-localisation of c-Myb footprints with 104 chromatin regulatory factors in K562 cells, and identified nine proteins that are enriched together with c-Myb footprints on genes positively regulated by c-Myb and one protein enriched on negatively regulated genes. Our data suggest that c-Myb is a transcription factor with multifaceted target regulation depending on cell type. PMID:26208222

  9. Genome-wide characterization and comparative analysis of R2R3-MYB transcription factors shows the complexity of MYB-associated regulatory networks in Salvia miltiorrhiza

    PubMed Central

    2014-01-01

    Background MYB is the largest plant transcription factor gene family playing vital roles in plant growth and development. However, it has not been systematically studied in Salvia miltiorrhiza, an economically important medicinal plant. Results Here we report the genome-wide identification and characterization of 110 R2R3-MYBs, the largest subfamily of MYBs in S. miltiorrhiza. The MYB domain and other motifs of SmMYBs are largely conserved with Arabidopsis AtMYBs, whereas the divergence of SmMYBs and AtMYBs also exists, suggesting the conservation and diversity of plant MYBs. SmMYBs and AtMYBs may be classified into 37 subgroups, of which 31 include proteins from S. miltiorrhiza and Arabidopsis, whereas 6 are specific to a species, indicating that the majority of MYBs play conserved roles, while others may exhibit species-specialized functions. SmMYBs are differentially expressed in various tissues of S. miltiorrhiza. The expression profiles are largely consistent with known functions of their Arabidopsis counterparts. The expression of a subset of SmMYBs is regulated by microRNAs, such as miR159, miR319, miR828 and miR858. Based on functional conservation of MYBs in a subgroup, SmMYBs potentially involved in the biosynthesis of bioactive compounds were identified. Conclusions A total of 110 R2R3-MYBs were identified and analyzed. The results suggest the complexity of MYB-mediated regulatory networks in S. miltiorrhiza and provide a foundation for understanding the regulatory mechanism of SmMYBs. PMID:24725266

  10. Characterization of a Citrus R2R3-MYB Transcription Factor that Regulates the Flavonol and Hydroxycinnamic Acid Biosynthesis.

    PubMed

    Liu, Chaoyang; Long, Jianmei; Zhu, Kaijie; Liu, Linlin; Yang, Wei; Zhang, Hongyan; Li, Li; Xu, Qiang; Deng, Xiuxin

    2016-01-01

    Flavonols and hydroxycinnamic acids are important phenylpropanoid metabolites in plants. In this study, we isolated and characterized a citrus R2R3-MYB transcription factor CsMYBF1, encoding a protein belonging to the flavonol-specific MYB subgroup. Ectopic expression of CsMYBF1 in tomato led to an up-regulation of a series of genes involved in primary metabolism and the phenylpropanoid pathway, and induced a strong accumulation of hydroxycinnamic acid compounds but not the flavonols. The RNAi suppression of CsMYBF1 in citrus callus caused a down-regulation of many phenylpropanoid pathway genes and reduced the contents of hydroxycinnamic acids and flavonols. Transactivation assays indicated that CsMYBF1 activated several promoters of phenylpropanoid pathway genes in tomato and citrus. Interestingly, CsMYBF1 could activate the CHS gene promoter in citrus, but not in tomato. Further examinations revealed that the MYBPLANT cis-elements were essential for CsMYBF1 in activating phenylpropanoid pathway genes. In summary, our data indicated that CsMYBF1 possessed the function in controlling the flavonol and hydroxycinnamic acid biosynthesis, and the regulatory differences in the target metabolite accumulation between two species may be due to the differential activation of CHS promoters by CsMYBF1. Therefore, CsMYBF1 constitutes an important gene source for the engineering of specific phenylpropanoid components. PMID:27162196

  11. Characterization of a Citrus R2R3-MYB Transcription Factor that Regulates the Flavonol and Hydroxycinnamic Acid Biosynthesis

    PubMed Central

    Liu, Chaoyang; Long, Jianmei; Zhu, Kaijie; Liu, Linlin; Yang, Wei; Zhang, Hongyan; Li, Li; Xu, Qiang; Deng, Xiuxin

    2016-01-01

    Flavonols and hydroxycinnamic acids are important phenylpropanoid metabolites in plants. In this study, we isolated and characterized a citrus R2R3-MYB transcription factor CsMYBF1, encoding a protein belonging to the flavonol-specific MYB subgroup. Ectopic expression of CsMYBF1 in tomato led to an up-regulation of a series of genes involved in primary metabolism and the phenylpropanoid pathway, and induced a strong accumulation of hydroxycinnamic acid compounds but not the flavonols. The RNAi suppression of CsMYBF1 in citrus callus caused a down-regulation of many phenylpropanoid pathway genes and reduced the contents of hydroxycinnamic acids and flavonols. Transactivation assays indicated that CsMYBF1 activated several promoters of phenylpropanoid pathway genes in tomato and citrus. Interestingly, CsMYBF1 could activate the CHS gene promoter in citrus, but not in tomato. Further examinations revealed that the MYBPLANT cis-elements were essential for CsMYBF1 in activating phenylpropanoid pathway genes. In summary, our data indicated that CsMYBF1 possessed the function in controlling the flavonol and hydroxycinnamic acid biosynthesis, and the regulatory differences in the target metabolite accumulation between two species may be due to the differential activation of CHS promoters by CsMYBF1. Therefore, CsMYBF1 constitutes an important gene source for the engineering of specific phenylpropanoid components. PMID:27162196

  12. Characterization of a Citrus R2R3-MYB Transcription Factor that Regulates the Flavonol and Hydroxycinnamic Acid Biosynthesis.

    PubMed

    Liu, Chaoyang; Long, Jianmei; Zhu, Kaijie; Liu, Linlin; Yang, Wei; Zhang, Hongyan; Li, Li; Xu, Qiang; Deng, Xiuxin

    2016-05-10

    Flavonols and hydroxycinnamic acids are important phenylpropanoid metabolites in plants. In this study, we isolated and characterized a citrus R2R3-MYB transcription factor CsMYBF1, encoding a protein belonging to the flavonol-specific MYB subgroup. Ectopic expression of CsMYBF1 in tomato led to an up-regulation of a series of genes involved in primary metabolism and the phenylpropanoid pathway, and induced a strong accumulation of hydroxycinnamic acid compounds but not the flavonols. The RNAi suppression of CsMYBF1 in citrus callus caused a down-regulation of many phenylpropanoid pathway genes and reduced the contents of hydroxycinnamic acids and flavonols. Transactivation assays indicated that CsMYBF1 activated several promoters of phenylpropanoid pathway genes in tomato and citrus. Interestingly, CsMYBF1 could activate the CHS gene promoter in citrus, but not in tomato. Further examinations revealed that the MYBPLANT cis-elements were essential for CsMYBF1 in activating phenylpropanoid pathway genes. In summary, our data indicated that CsMYBF1 possessed the function in controlling the flavonol and hydroxycinnamic acid biosynthesis, and the regulatory differences in the target metabolite accumulation between two species may be due to the differential activation of CHS promoters by CsMYBF1. Therefore, CsMYBF1 constitutes an important gene source for the engineering of specific phenylpropanoid components.

  13. A complex interplay of three R2R3 MYB transcription factors determines the profile of aliphatic glucosinolates in Arabidopsis.

    PubMed

    Sønderby, Ida Elken; Burow, Meike; Rowe, Heather C; Kliebenstein, Daniel J; Halkier, Barbara Ann

    2010-05-01

    While R2R3 MYB transcription factors are a large gene family of transcription factors within plants, comprehensive functional data in planta are still scarce. A model for studying R2R3 MYB control of metabolic networks is the glucosinolates (GLSs), secondary metabolites that control plant resistance against insects and pathogens and carry cancer-preventive properties. Three related members of the R2R3 MYB transcription factor family within Arabidopsis (Arabidopsis thaliana), MYB28, MYB29, and MYB76, are the commonly defined regulators of aliphatic GLS biosynthesis. We utilized new genotypes and systems analysis techniques to test the existing regulatory model in which MYB28 is the dominant regulator, MYB29 plays a minor rheostat role, and MYB76 is largely uninvolved. We unequivocally show that MYB76 is not dependent on MYB28 and MYB29 for induction of aliphatic GLSs and that MYB76 plays a role in determining the spatial distribution of aliphatic GLSs within the leaf, pointing at a potential role of MYB76 in transport regulation. Transcriptional profiling of knockout mutants revealed that GLS metabolite levels are uncoupled from the level of transcript accumulation for aliphatic GLS biosynthetic genes. This uncoupling of chemotypes from biosynthetic transcripts suggests revising our view of the regulation of GLS metabolism from a simple linear transcription factor-promoter model to a more modular system in which transcription factors cause similar chemotypes via nonoverlapping regulatory patterns. Similar regulatory networks might exist in other secondary pathways.

  14. The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patterns of Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula.

    PubMed

    Jun, Ji Hyung; Liu, Chenggang; Xiao, Xirong; Dixon, Richard A

    2015-10-01

    Accumulation of anthocyanins and proanthocyanidins (PAs) is limited to specific cell types and developmental stages, but little is known about how antagonistically acting transcriptional regulators work together to determine temporal and spatial patterning of pigmentation at the cellular level, especially for PAs. Here, we characterize MYB2, a transcriptional repressor regulating both anthocyanin and PA biosynthesis in the model legume Medicago truncatula. MYB2 was strongly upregulated by MYB5, a major regulator of PA biosynthesis in M. truncatula and a component of MYB-basic helix loop helix-WD40 (MBW) activator complexes. Overexpression of MYB2 abolished anthocyanin and PA accumulation in M. truncatula hairy roots and Arabidopsis thaliana seeds, respectively. Anthocyanin deposition was expanded in myb2 mutant seedlings and flowers accompanied by increased anthocyanin content. PA mainly accumulated in the epidermal layer derived from the outer integument in the M. truncatula seed coat, starting from the hilum area. The area of PA accumulation and ANTHOCYANIDIN REDUCTASE expression was expanded into the seed body at the early stage of seed development in the myb2 mutant. Genetic, biochemical, and cell biological evidence suggests that MYB2 functions as part of a multidimensional regulatory network to define the temporal and spatial pattern of anthocyanin and PA accumulation linked to developmental processes.

  15. Genome-wide analysis of the R2R3-MYB transcription factor gene family in sweet orange (Citrus sinensis).

    PubMed

    Liu, Chaoyang; Wang, Xia; Xu, Yuantao; Deng, Xiuxin; Xu, Qiang

    2014-10-01

    MYB transcription factor represents one of the largest gene families in plant genomes. Sweet orange (Citrus sinensis) is one of the most important fruit crops worldwide, and recently the genome has been sequenced. This provides an opportunity to investigate the organization and evolutionary characteristics of sweet orange MYB genes from whole genome view. In the present study, we identified 100 R2R3-MYB genes in the sweet orange genome. A comprehensive analysis of this gene family was performed, including the phylogeny, gene structure, chromosomal localization and expression pattern analyses. The 100 genes were divided into 29 subfamilies based on the sequence similarity and phylogeny, and the classification was also well supported by the highly conserved exon/intron structures and motif composition. The phylogenomic comparison of MYB gene family among sweet orange and related plant species, Arabidopsis, cacao and papaya suggested the existence of functional divergence during evolution. Expression profiling indicated that sweet orange R2R3-MYB genes exhibited distinct temporal and spatial expression patterns. Our analysis suggested that the sweet orange MYB genes may play important roles in different plant biological processes, some of which may be potentially involved in citrus fruit quality. These results will be useful for future functional analysis of the MYB gene family in sweet orange.

  16. Myb-binding site regulates the expression of glucosamine-6-phosphate isomerase in Dictyostelium discoideum.

    PubMed

    Tabata, K; Matsuda, Y; Viller, E; Masamune, Y; Katayama, T; Yasukawa, H

    2001-10-01

    A homolog of the glucosamine-6-phosphate isomerase in the cellular slime mold Dictyostelium discoideum has been analyzed. The gene disruption mutant was arrested at the mound stage, demonstrating that the gene is important for development. The gene was expressed in vegetatively growing cells, silenced on starvation and expressed again in prestalk cells during the multicellular stages. The upstream region of the gene (1376 bp relative to ATG) was cloned and sequenced to study the transcription control mechanisms. Analysis of deletion mutants and a site-directed mutant indicated that the Myb-binding sequence (5'-AACTG-3') localized in the upstream region is important for gene expression. The results of gel-shift assays showed the presence of an Myb-related protein binding to the sequence at the growing phase and another protein binding to the sequence at developmental stages. PMID:11576175

  17. The Arabidopsis thaliana MYB60 promoter provides a tool for the spatio-temporal control of gene expression in stomatal guard cells.

    PubMed

    Rusconi, Fabio; Simeoni, Fabio; Francia, Priscilla; Cominelli, Eleonora; Conti, Lucio; Riboni, Matteo; Simoni, Laura; Martin, Cathie R; Tonelli, Chiara; Galbiati, Massimo

    2013-08-01

    Plants have evolved different strategies to resist drought, of which the best understood is the abscisic acid (ABA)-induced closure of stomatal pores to reduce water loss by transpiration. The availability of useful promoters that allow for precise spatial and temporal control of gene expression in stomata is essential both for investigating stomatal regulation in model systems and for biotechnological applications in field crops. Previous work indicated that the regulatory region of the transcription factor AtMYB60 specifically drives gene expression in guard cells of Arabidopsis, although its activity is rapidly down-regulated by ABA. Here, the activity of the full-length and minimal AtMYB60 promoters is reported in rice (Oryza sativa), tobacco (Nicotiana tabacum), and tomato (Solanum lycopersicum), using a reporter gene approach. In rice, the activity of both promoters was completely abolished, whereas it was spatially restricted to guard cells in tobacco and tomato. To overcome the negative effect of ABA on the AtMYB60 promoter, a chimeric inducible system was developed, which combined the cellular specificity of the AtMYB60 minimal promoter with the positive responsiveness to dehydration and ABA of the rd29A promoter. Remarkably, the synthetic module specifically up-regulated gene expression in guard cells of Arabidopsis, tobacco, and tomato in response to dehydration or ABA. The comparative analysis of different native and synthetic regulatory modules derived from the AtMYB60 promoter offers new insights into the functional conservation of the cis-mechanisms that mediate gene expression in guard cells in distantly related dicotyledonous species and provides novel tools for modulating stomatal activity in plants.

  18. Soybean GmMYB73 promotes lipid accumulation in transgenic plants

    PubMed Central

    2014-01-01

    Background Soybean is one of the most important oil crops. The regulatory genes involved in oil accumulation are largely unclear. We initiated studies to identify genes that regulate this process. Results One MYB-type gene GmMYB73 was found to display differential expression in soybean seeds of different developing stages by microarray analysis and was further investigated for its functions in lipid accumulation. GmMYB73 is a small protein with single MYB repeat and has similarity to CPC-like MYB proteins from Arabidopsis. GmMYB73 interacted with GL3 and EGL3, and then suppressed GL2, a negative regulator of oil accumulation. GmMYB73 overexpression enhanced lipid contents in both seeds and leaves of transgenic Arabidopsis plants. Seed length and thousand-seed weight were also promoted. GmMYB73 introduction into the Arabidopsis try cpc double mutant rescued the total lipids, seed size and thousand-seed weight. GmMYB73 also elevated lipid levels in seeds and leaves of transgenic Lotus, and in transgenic hairy roots of soybean plants. GmMYB73 promoted PLDα1 expression, whose promoter can be bound and inhibited by GL2. PLDα1 mutation reduced triacylglycerol levels mildly in seeds but significantly in leaves of Arabidopsis plants. Conclusions GmMYB73 may reduce GL2, and then release GL2-inhibited PLDα1 expression for lipid accumulation. Manipulation of GmMYB73 may potentially improve oil production in legume crop plants. PMID:24655684

  19. Long Noncoding RNA MALAT1 Controls Cell Cycle Progression by Regulating the Expression of Oncogenic Transcription Factor B-MYB

    PubMed Central

    Tripathi, Vidisha; Shen, Zhen; Chakraborty, Arindam; Giri, Sumanprava; Freier, Susan M.; Wu, Xiaolin; Zhang, Yongqing; Gorospe, Myriam; Prasanth, Supriya G.; Lal, Ashish; Prasanth, Kannanganattu V.

    2013-01-01

    The long noncoding MALAT1 RNA is upregulated in cancer tissues and its elevated expression is associated with hyper-proliferation, but the underlying mechanism is poorly understood. We demonstrate that MALAT1 levels are regulated during normal cell cycle progression. Genome-wide transcriptome analyses in normal human diploid fibroblasts reveal that MALAT1 modulates the expression of cell cycle genes and is required for G1/S and mitotic progression. Depletion of MALAT1 leads to activation of p53 and its target genes. The cell cycle defects observed in MALAT1-depleted cells are sensitive to p53 levels, indicating that p53 is a major downstream mediator of MALAT1 activity. Furthermore, MALAT1-depleted cells display reduced expression of B-MYB (Mybl2), an oncogenic transcription factor involved in G2/M progression, due to altered binding of splicing factors on B-MYB pre-mRNA and aberrant alternative splicing. In human cells, MALAT1 promotes cellular proliferation by modulating the expression and/or pre-mRNA processing of cell cycle–regulated transcription factors. These findings provide mechanistic insights on the role of MALAT1 in regulating cellular proliferation. PMID:23555285

  20. MYB Transcription Factors in Chinese Pear (Pyrus bretschneideri Rehd.): Genome-Wide Identification, Classification, and Expression Profiling during Fruit Development.

    PubMed

    Cao, Yunpeng; Han, Yahui; Li, Dahui; Lin, Yi; Cai, Yongping

    2016-01-01

    The MYB family is one of the largest families of transcription factors in plants. Although, some MYBs were reported to play roles in secondary metabolism, no comprehensive study of the MYB family in Chinese pear (Pyrus bretschneideri Rehd.) has been reported. In the present study, we performed genome-wide analysis of MYB genes in Chinese pear, designated as PbMYBs, including analyses of their phylogenic relationships, structures, chromosomal locations, promoter regions, GO annotations, and collinearity. A total of 129 PbMYB genes were identified in the pear genome and were divided into 31 subgroups based on phylogenetic analysis. These PbMYBs were unevenly distributed among 16 chromosomes (total of 17 chromosomes). The occurrence of gene duplication events indicated that whole-genome duplication and segmental duplication likely played key roles in expansion of the PbMYB gene family. Ka/Ks analysis suggested that the duplicated PbMYBs mainly experienced purifying selection with restrictive functional divergence after the duplication events. Interspecies microsynteny analysis revealed maximum orthology between pear and peach, followed by plum and strawberry. Subsequently, the expression patterns of 20 PbMYB genes that may be involved in lignin biosynthesis according to their phylogenetic relationships were examined throughout fruit development. Among the 20 genes examined, PbMYB25 and PbMYB52 exhibited expression patterns consistent with the typical variations in the lignin content previously reported. Moreover, sub-cellular localization analysis revealed that two proteins PbMYB25 and PbMYB52 were localized to the nucleus. All together, PbMYB25 and PbMYB52 were inferred to be candidate genes involved in the regulation of lignin biosynthesis during the development of pear fruit. This study provides useful information for further functional analysis of the MYB gene family in pear. PMID:27200050

  1. MYB Transcription Factors in Chinese Pear (Pyrus bretschneideri Rehd.): Genome-Wide Identification, Classification, and Expression Profiling during Fruit Development.

    PubMed

    Cao, Yunpeng; Han, Yahui; Li, Dahui; Lin, Yi; Cai, Yongping

    2016-01-01

    The MYB family is one of the largest families of transcription factors in plants. Although, some MYBs were reported to play roles in secondary metabolism, no comprehensive study of the MYB family in Chinese pear (Pyrus bretschneideri Rehd.) has been reported. In the present study, we performed genome-wide analysis of MYB genes in Chinese pear, designated as PbMYBs, including analyses of their phylogenic relationships, structures, chromosomal locations, promoter regions, GO annotations, and collinearity. A total of 129 PbMYB genes were identified in the pear genome and were divided into 31 subgroups based on phylogenetic analysis. These PbMYBs were unevenly distributed among 16 chromosomes (total of 17 chromosomes). The occurrence of gene duplication events indicated that whole-genome duplication and segmental duplication likely played key roles in expansion of the PbMYB gene family. Ka/Ks analysis suggested that the duplicated PbMYBs mainly experienced purifying selection with restrictive functional divergence after the duplication events. Interspecies microsynteny analysis revealed maximum orthology between pear and peach, followed by plum and strawberry. Subsequently, the expression patterns of 20 PbMYB genes that may be involved in lignin biosynthesis according to their phylogenetic relationships were examined throughout fruit development. Among the 20 genes examined, PbMYB25 and PbMYB52 exhibited expression patterns consistent with the typical variations in the lignin content previously reported. Moreover, sub-cellular localization analysis revealed that two proteins PbMYB25 and PbMYB52 were localized to the nucleus. All together, PbMYB25 and PbMYB52 were inferred to be candidate genes involved in the regulation of lignin biosynthesis during the development of pear fruit. This study provides useful information for further functional analysis of the MYB gene family in pear.

  2. MYB Transcription Factors in Chinese Pear (Pyrus bretschneideri Rehd.): Genome-Wide Identification, Classification, and Expression Profiling during Fruit Development

    PubMed Central

    Cao, Yunpeng; Han, Yahui; Li, Dahui; Lin, Yi; Cai, Yongping

    2016-01-01

    The MYB family is one of the largest families of transcription factors in plants. Although, some MYBs were reported to play roles in secondary metabolism, no comprehensive study of the MYB family in Chinese pear (Pyrus bretschneideri Rehd.) has been reported. In the present study, we performed genome-wide analysis of MYB genes in Chinese pear, designated as PbMYBs, including analyses of their phylogenic relationships, structures, chromosomal locations, promoter regions, GO annotations, and collinearity. A total of 129 PbMYB genes were identified in the pear genome and were divided into 31 subgroups based on phylogenetic analysis. These PbMYBs were unevenly distributed among 16 chromosomes (total of 17 chromosomes). The occurrence of gene duplication events indicated that whole-genome duplication and segmental duplication likely played key roles in expansion of the PbMYB gene family. Ka/Ks analysis suggested that the duplicated PbMYBs mainly experienced purifying selection with restrictive functional divergence after the duplication events. Interspecies microsynteny analysis revealed maximum orthology between pear and peach, followed by plum and strawberry. Subsequently, the expression patterns of 20 PbMYB genes that may be involved in lignin biosynthesis according to their phylogenetic relationships were examined throughout fruit development. Among the 20 genes examined, PbMYB25 and PbMYB52 exhibited expression patterns consistent with the typical variations in the lignin content previously reported. Moreover, sub-cellular localization analysis revealed that two proteins PbMYB25 and PbMYB52 were localized to the nucleus. All together, PbMYB25 and PbMYB52 were inferred to be candidate genes involved in the regulation of lignin biosynthesis during the development of pear fruit. This study provides useful information for further functional analysis of the MYB gene family in pear. PMID:27200050

  3. Interactions between the R2R3-MYB transcription factor, AtMYB61, and target DNA binding sites.

    PubMed

    Prouse, Michael B; Campbell, Malcolm M

    2013-01-01

    Despite the prominent roles played by R2R3-MYB transcription factors in the regulation of plant gene expression, little is known about the details of how these proteins interact with their DNA targets. For example, while Arabidopsis thaliana R2R3-MYB protein AtMYB61 is known to alter transcript abundance of a specific set of target genes, little is known about the specific DNA sequences to which AtMYB61 binds. To address this gap in knowledge, DNA sequences bound by AtMYB61 were identified using cyclic amplification and selection of targets (CASTing). The DNA targets identified using this approach corresponded to AC elements, sequences enriched in adenosine and cytosine nucleotides. The preferred target sequence that bound with the greatest affinity to AtMYB61 recombinant protein was ACCTAC, the AC-I element. Mutational analyses based on the AC-I element showed that ACC nucleotides in the AC-I element served as the core recognition motif, critical for AtMYB61 binding. Molecular modelling predicted interactions between AtMYB61 amino acid residues and corresponding nucleotides in the DNA targets. The affinity between AtMYB61 and specific target DNA sequences did not correlate with AtMYB61-driven transcriptional activation with each of the target sequences. CASTing-selected motifs were found in the regulatory regions of genes previously shown to be regulated by AtMYB61. Taken together, these findings are consistent with the hypothesis that AtMYB61 regulates transcription from specific cis-acting AC elements in vivo. The results shed light on the specifics of DNA binding by an important family of plant-specific transcriptional regulators. PMID:23741471

  4. MdSOS2L1 forms a complex with MdMYB1 to control vacuolar pH by transcriptionally regulating MdVHA-B1 in apples.

    PubMed

    Sun, Cui-Hui; Zhang, Quan-Yan; Sun, Mei-Hong; Hu, Da-Gang

    2016-01-01

    Vacuolar pH is important and involves in many different physiological processes in plants. A recent paper published in Plant Physiology reveals that MdMYB1 regulates vacuolar pH by directly transcriptionally regulating proton pump genes and malate transporters genes, such as V-ATPase subunit gene MdVHA-B1. Here, we found that MdSOS2L1 in vitro did not directly interact with MdMYB1, however, in vivo formed a complex with MdMYB1 in the nucleus to regulate MdVHA-B1-mediated vacuolar acidification. This finding shed light on the role of MdSOS2L1 in transcriptionally regulating MdVHA-B1 in addition to its post-modified function in apples. PMID:26910596

  5. Fruit-Surface Flavonoid Accumulation in Tomato Is Controlled by a SlMYB12-Regulated Transcriptional Network

    PubMed Central

    Mintz-Oron, Shira; Venger, Ilya; Levy, Dorit; Yativ, Merav; Domínguez, Eva; Wang, Zhonghua; De Vos, Ric C. H.; Jetter, Reinhard; Schreiber, Lukas; Heredia, Antonio; Rogachev, Ilana; Aharoni, Asaph

    2009-01-01

    The cuticle covering plants' aerial surfaces is a unique structure that plays a key role in organ development and protection against diverse stress conditions. A detailed analysis of the tomato colorless-peel y mutant was carried out in the framework of studying the outer surface of reproductive organs. The y mutant peel lacks the yellow flavonoid pigment naringenin chalcone, which has been suggested to influence the characteristics and function of the cuticular layer. Large-scale metabolic and transcript profiling revealed broad effects on both primary and secondary metabolism, related mostly to the biosynthesis of phenylpropanoids, particularly flavonoids. These were not restricted to the fruit or to a specific stage of its development and indicated that the y mutant phenotype is due to a mutation in a regulatory gene. Indeed, expression analyses specified three R2R3-MYB–type transcription factors that were significantly down-regulated in the y mutant fruit peel. One of these, SlMYB12, was mapped to the genomic region on tomato chromosome 1 previously shown to harbor the y mutation. Identification of an additional mutant allele that co-segregates with the colorless-peel trait, specific down-regulation of SlMYB12 and rescue of the y phenotype by overexpression of SlMYB12 on the mutant background, confirmed that a lesion in this regulator underlies the y phenotype. Hence, this work provides novel insight to the study of fleshy fruit cuticular structure and paves the way for the elucidation of the regulatory network that controls flavonoid accumulation in tomato fruit cuticle. PMID:20019811

  6. PyMYB10 and PyMYB10.1 Interact with bHLH to Enhance Anthocyanin Accumulation in Pears

    PubMed Central

    Feng, Shouqian; Sun, Shasha; Chen, Xiaoliu; Wu, Shujing; Wang, Deyun; Chen, Xuesen

    2015-01-01

    Color is an important agronomic trait of pears, and the anthocyanin content of fruit is immensely significant for pear coloring. In this study, an anthocyanin-activating R2R3-MYB transcription factor gene, PyMYB10.1, was isolated from fruits of red sand pear (Pyrus pyrifolia cv. Aoguan). Alignments of the nucleotide and amino acid sequences suggested that PyMYB10.1 was involved in anthocyanin regulation. Similar to PyMYB10, PyMYB10.1 was predominantly expressed in red tissues, including the skin, leaf and flower, but it was minimally expressed in non-red fruit flesh. The expression of this gene could be induced by light. Dual-luciferase assays indicated that both PyMYB10 and PyMYB10.1 activated the AtDFR promoter. The activation of AtDFR increased to a greater extent when combined with a bHLH co-factor, such as PybHLH, MrbHLH1, MrbHLH2, or AtbHLH2. However, the response of this activation depended on the protein complex formed. PyMYB10-AtbHLH2 activated the AtDFR promoter to a greater extent than other combinations of proteins. PyMYB10-AtbHLH2 also induced the highest anthocyanin accumulation in tobacco transient-expression assays. Moreover, PybHLH interacted with PyMYB10 and PyMYB10.1. These results suggest that both PyMYB10 and PyMYB10.1 are positive anthocyanin biosynthesis regulators in pears that act via the formation of a ternary complex with PybHLH. The functional characterization of PyMYB10 and PyMYB10.1 will aid further understanding of the anthocyanin regulation in pears. PMID:26536358

  7. The Arabidopsis MYB96 Transcription Factor Is a Positive Regulator of ABSCISIC ACID-INSENSITIVE4 in the Control of Seed Germination.

    PubMed

    Lee, Kyounghee; Lee, Hong Gil; Yoon, Seongmun; Kim, Hyun Uk; Seo, Pil Joon

    2015-06-01

    Seed germination is a key developmental transition that initiates the plant life cycle. The timing of germination is determined by the coordinated action of two phytohormones, gibberellin and abscisic acid (ABA). In particular, ABA plays a key role in integrating environmental information and inhibiting the germination process. The utilization of embryonic lipid reserves contributes to seed germination by acting as an energy source, and ABA suppresses lipid degradation to modulate the germination process. Here, we report that the ABA-responsive R2R3-type MYB transcription factor MYB96, which is highly expressed in embryo, regulates seed germination by controlling the expression of abscisic acid-insensitive4 (ABI4) in Arabidopsis (Arabidopsis thaliana). In the presence of ABA, germination was accelerated in MYB96-deficient myb96-1 seeds, whereas the process was significantly delayed in MYB96-overexpressing activation-tagging myb96-ox seeds. Consistently, myb96-1 seeds degraded a larger extent of lipid reserves even in the presence of ABA, while reduced lipid mobilization was observed in myb96-ox seeds. MYB96 directly regulates ABI4, which acts as a repressor of lipid breakdown, to define its spatial and temporal expression. Genetic analysis further demonstrated that ABI4 is epistatic to MYB96 in the control of seed germination. Taken together, the MYB96-ABI4 module regulates lipid mobilization specifically in the embryo to ensure proper seed germination under suboptimal conditions.

  8. The Arabidopsis MYB96 Transcription Factor Is a Positive Regulator of ABSCISIC ACID-INSENSITIVE4 in the Control of Seed Germination1

    PubMed Central

    Lee, Kyounghee; Lee, Hong Gil; Kim, Hyun Uk; Seo, Pil Joon

    2015-01-01

    Seed germination is a key developmental transition that initiates the plant life cycle. The timing of germination is determined by the coordinated action of two phytohormones, gibberellin and abscisic acid (ABA). In particular, ABA plays a key role in integrating environmental information and inhibiting the germination process. The utilization of embryonic lipid reserves contributes to seed germination by acting as an energy source, and ABA suppresses lipid degradation to modulate the germination process. Here, we report that the ABA-responsive R2R3-type MYB transcription factor MYB96, which is highly expressed in embryo, regulates seed germination by controlling the expression of ABSCISIC ACID-INSENSITIVE4 (ABI4) in Arabidopsis (Arabidopsis thaliana). In the presence of ABA, germination was accelerated in MYB96-deficient myb96-1 seeds, whereas the process was significantly delayed in MYB96-overexpressing activation-tagging myb96-ox seeds. Consistently, myb96-1 seeds degraded a larger extent of lipid reserves even in the presence of ABA, while reduced lipid mobilization was observed in myb96-ox seeds. MYB96 directly regulates ABI4, which acts as a repressor of lipid breakdown, to define its spatial and temporal expression. Genetic analysis further demonstrated that ABI4 is epistatic to MYB96 in the control of seed germination. Taken together, the MYB96-ABI4 module regulates lipid mobilization specifically in the embryo to ensure proper seed germination under suboptimal conditions. PMID:25869652

  9. Effects of seasonal temperature changes on DkMyb4 expression involved in proanthocyanidin regulation in two genotypes of persimmon (Diospyros kaki Thunb.) fruit.

    PubMed

    Akagi, Takashi; Tsujimoto, Tomoyuki; Ikegami, Ayako; Yonemori, Keizo

    2011-05-01

    Persimmon fruits accumulate a large amount of proanthocyanidin (PA). Fruits of the mutant non-astringent (NA) type lose their ability to accumulate PA at an early stage of fruit development, whereas fruits of the normal astringent (A) type sustain PA accumulation until ripening. This allelotype is determined by the genotype of a single ASTRINGENCY (AST) locus. It is possible that the reduction in PA accumulation in NA-type fruits is due to phenological down-regulation of DkMyb4 (a PA regulator) and the resultant down-regulation of structural genes in the PA pathway. In this study, attempts were made to identify the regulatory mechanisms of phenological PA accumulation in A- and NA-type fruits, focusing particularly on the effects of ambient temperature. Continuous cool temperature conditions caused sustained expression of DkMyb4 in NA-type fruits, as well as in A-type fruits, resulting in increased expression of PA pathway genes and PA accumulation. However, the expression of some A/NA phenotypic marker genes was not significantly affected by the cool temperature conditions. In addition, PA composition in NA-type fruits exposed to cool temperatures differed from that in A-type fruits. These results indicate that a cool ambient temperature may have induced DkMyb4 expression and resultant PA accumulation, but did not directly affect the expression of the AST gene.

  10. The MYB-NFIB gene fusion-a novel genetic link between adenoid cystic carcinoma and dermal cylindroma.

    PubMed

    Fehr, A; Kovács, A; Löning, T; Frierson, Hf; van den Oord, Jj; Stenman, G

    2011-07-01

    We have recently shown that the recurrent t(6;9)(q22 ∼ 23;p23 ∼ 24) translocation in adenoid cystic carcinoma (ACC) of the breast and head and neck results in a fusion of the two transcription factor genes MYB and NFIB. Here we demonstrate, for the first time, that benign sporadic, dermal cylindromas also express the MYB-NFIB gene fusion. RT-PCR and immunohistochemical analyses revealed that eight of 12 analysed tumours (67%) expressed MYB-NFIB fusion transcripts and/or stained positive for MYB protein. Nucleotide sequence analyses confirmed that the composition of the chimeric transcript variants identified was identical to that in ACC, suggesting a similar molecular mechanism of activation of MYB in cylindroma as in ACC. In contrast, no evidence for the presence of the MYB-NFIB fusion was found in other types of basaloid skin and salivary gland tumours, indicating that the fusion indeed has a restricted expression pattern. Our findings broaden the spectrum of neoplasms associated with MYB oncogene activation and reveal a novel genetic link between ACC and dermal cylindroma. These results, together with our previous observations, further strengthen the evidence for common molecular pathways of importance for the development of both benign and malignant breast, salivary and adnexal tumours.

  11. MdCOP1 Ubiquitin E3 Ligases Interact with MdMYB1 to Regulate Light-Induced Anthocyanin Biosynthesis and Red Fruit Coloration in Apple1[W][OA

    PubMed Central

    Li, Yuan-Yuan; Mao, Ke; Zhao, Cheng; Zhao, Xian-Yan; Zhang, Hua-Lei; Shu, Huai-Rui; Hao, Yu-Jin

    2012-01-01

    MdMYB1 is a crucial regulator of light-induced anthocyanin biosynthesis and fruit coloration in apple (Malus domestica). In this study, it was found that MdMYB1 protein accumulated in the light but degraded via a ubiquitin-dependent pathway in the dark. Subsequently, the MdCOP1-1 and MdCOP1-2 genes were isolated from apple fruit peel and were functionally characterized in the Arabidopsis (Arabidopsis thaliana) cop1-4 mutant. Yeast (Saccharomyces cerevisiae) two-hybrid, bimolecular fluorescence complementation, and coimmunoprecipitation assays showed that MdMYB1 interacts with the MdCOP1 proteins. Furthermore, in vitro and in vivo experiments indicated that MdCOP1s are necessary for the ubiquitination and degradation of MdMYB1 protein in the dark and are therefore involved in the light-controlled stability of the MdMYB1 protein. Finally, a viral vector-based transformation approach demonstrated that MdCOP1s negatively regulate the peel coloration of apple fruits by modulating the degradation of the MdMYB1 protein. Our findings provide new insight into the mechanism by which light controls anthocyanin accumulation and red fruit coloration in apple and even other plant species. PMID:22855936

  12. A single-repeat R3-MYB transcription factor MYBC1 negatively regulates freezing tolerance in Arabidopsis

    SciTech Connect

    Zhai, Hong; Bai, Xi; Zhu, Yanming; Li, Yong; Cai, Hua; Ji, Wei; Ji, Zuojun; Liu, Xiaofei; Liu, Xin; Li, Jing

    2010-04-16

    We had previously identified the MYBC1 gene, which encodes a single-repeat R3-MYB protein, as a putative osmotic responding gene; however, no R3-MYB transcription factor has been reported to regulate osmotic stress tolerance. Thus, we sought to elucidate the function of MYBC1 in response to osmotic stresses. Real-time RT-PCR analysis indicated that MYBC1 expression responded to cold, dehydration, salinity and exogenous ABA at the transcript level. mybc1 mutants exhibited an increased tolerance to freezing stress, whereas 35S::MYBC1 transgenic plants exhibited decreased cold tolerance. Transcript levels of some cold-responsive genes, including CBF/DREB genes, KIN1, ADC1, ADC2 and ZAT12, though, were not altered in the mybc1 mutants or the 35S::MYBC1 transgenic plants in response to cold stress, as compared to the wild type. Microarray analysis results that are publically available were investigated and found transcript level of MYBC1 was not altered by overexpression of CBF1, CBF2, and CBF3, suggesting that MYBC1 is not down regulated by these CBF family members. Together, these results suggested that MYBC1is capable of negatively regulating the freezing tolerance of Arabidopsis in the CBF-independent pathway. In transgenic Arabidopsis carrying an MYBC1 promoter driven {beta}-glucuronidase (GUS) construct, GUS activity was observed in all tissues and was relatively stronger in the vascular tissues. Fused MYBC1 and GFP protein revealed that MYBC1 was localized exclusively in the nuclear compartment.

  13. A Unique Mutation in a MYB Gene Cosegregates with the Nectarine Phenotype in Peach

    PubMed Central

    Dondini, Luca; Pacheco, Igor; Dettori, Maria Teresa; Gazza, Laura; Scalabrin, Simone; Strozzi, Francesco; Tartarini, Stefano; Bassi, Daniele; Verde, Ignazio; Rossini, Laura

    2014-01-01

    Nectarines play a key role in peach industry; the fuzzless skin has implications for consumer acceptance. The peach/nectarine (G/g) trait was described as monogenic and previously mapped on chromosome 5. Here, the position of the G locus was delimited within a 1.1 cM interval (635 kb) based on linkage analysis of an F2 progeny from the cross ‘Contender’ (C, peach) x ‘Ambra’ (A, nectarine). Careful inspection of the genes annotated in the corresponding genomic sequence (Peach v1.0), coupled with variant discovery, led to the identification of MYB gene PpeMYB25 as a candidate for trichome formation on fruit skin. Analysis of genomic re-sequencing data from five peach/nectarine accessions pointed to the insertion of a LTR retroelement in exon 3 of the PpeMYB25 gene as the cause of the recessive glabrous phenotype. A functional marker (indelG) developed on the LTR insertion cosegregated with the trait in the CxA F2 progeny and was validated on a broad panel of genotypes, including all known putative donors of the nectarine trait. This marker was shown to efficiently discriminate between peach and nectarine plants, indicating that a unique mutational event gave rise to the nectarine trait and providing a useful diagnostic tool for early seedling selection in peach breeding programs. PMID:24595269

  14. Alternatively spliced products of the maize P gene encode proteins with homology to the DNA-binding domain of myb-like transcription factors.

    PubMed Central

    Grotewold, E; Athma, P; Peterson, T

    1991-01-01

    The Zea mays P gene has been postulated to regulate the biosynthetic pathway of a flavonoid-derived pigment in certain floral tissues [Styles, E. D. & Ceska, O. (1977) Can. J. Genet. Cytol. 19, 289-302]. We have characterized two P transcripts that are alternatively spliced at their 3' ends. One message of 1802 nucleotides encodes a 43.7-kDa protein with an N-terminal region showing approximately 40% homology to the DNA-binding domain of several members of the myb family of protooncogene proteins. A second message of 945 nucleotides encodes a 17.3-kDa protein that contains most of the myb-homologous domain but differs from the first protein at the C terminus. The deduced P-encoded proteins show an even higher homology (70%) in the myb-homologous domain to the maize regulatory gene C1. Additionally, the P and C1 genes are structurally similar in the sizes and positions of the first and second exons and first intron. We show that P is required for accumulation in the pericarp of transcripts of two genes (A1 and C2) encoding enzymes for flavonoid biosynthesis--genes also regulated by C1 in the aleurone. Images PMID:2052542

  15. β-Glucosidase BGLU42 is a MYB72-dependent key regulator of rhizobacteria-induced systemic resistance and modulates iron deficiency responses in Arabidopsis roots.

    PubMed

    Zamioudis, Christos; Hanson, Johannes; Pieterse, Corné M J

    2014-10-01

    Selected soil-borne rhizobacteria can trigger an induced systemic resistance (ISR) that is effective against a broad spectrum of pathogens. In Arabidopsis thaliana, the root-specific transcription factor MYB72 is required for the onset of ISR, but is also associated with plant survival under conditions of iron deficiency. Here, we investigated the role of MYB72 in both processes. To identify MYB72 target genes, we analyzed the root transcriptomes of wild-type Col-0, mutant myb72 and complemented 35S:FLAG-MYB72/myb72 plants in response to ISR-inducing Pseudomonas fluorescens WCS417. Five WCS417-inducible genes were misregulated in myb72 and complemented in 35S:FLAG-MYB72/myb72. Amongst these, we uncovered β-glucosidase BGLU42 as a novel component of the ISR signaling pathway. Overexpression of BGLU42 resulted in constitutive disease resistance, whereas the bglu42 mutant was defective in ISR. Furthermore, we found 195 genes to be constitutively upregulated in MYB72-overexpressing roots in the absence of WCS417. Many of these encode enzymes involved in the production of iron-mobilizing phenolic metabolites under conditions of iron deficiency. We provide evidence that BGLU42 is required for their release into the rhizosphere. Together, this work highlights a thus far unidentified link between the ability of beneficial rhizobacteria to stimulate systemic immunity and mechanisms induced by iron deficiency in host plants. PMID:25138267

  16. β-Glucosidase BGLU42 is a MYB72-dependent key regulator of rhizobacteria-induced systemic resistance and modulates iron deficiency responses in Arabidopsis roots.

    PubMed

    Zamioudis, Christos; Hanson, Johannes; Pieterse, Corné M J

    2014-10-01

    Selected soil-borne rhizobacteria can trigger an induced systemic resistance (ISR) that is effective against a broad spectrum of pathogens. In Arabidopsis thaliana, the root-specific transcription factor MYB72 is required for the onset of ISR, but is also associated with plant survival under conditions of iron deficiency. Here, we investigated the role of MYB72 in both processes. To identify MYB72 target genes, we analyzed the root transcriptomes of wild-type Col-0, mutant myb72 and complemented 35S:FLAG-MYB72/myb72 plants in response to ISR-inducing Pseudomonas fluorescens WCS417. Five WCS417-inducible genes were misregulated in myb72 and complemented in 35S:FLAG-MYB72/myb72. Amongst these, we uncovered β-glucosidase BGLU42 as a novel component of the ISR signaling pathway. Overexpression of BGLU42 resulted in constitutive disease resistance, whereas the bglu42 mutant was defective in ISR. Furthermore, we found 195 genes to be constitutively upregulated in MYB72-overexpressing roots in the absence of WCS417. Many of these encode enzymes involved in the production of iron-mobilizing phenolic metabolites under conditions of iron deficiency. We provide evidence that BGLU42 is required for their release into the rhizosphere. Together, this work highlights a thus far unidentified link between the ability of beneficial rhizobacteria to stimulate systemic immunity and mechanisms induced by iron deficiency in host plants.

  17. A R2R3-MYB Transcription Factor Regulates the Flavonol Biosynthetic Pathway in a Traditional Chinese Medicinal Plant, Epimedium sagittatum.

    PubMed

    Huang, Wenjun; Khaldun, A B M; Chen, Jianjun; Zhang, Chanjuan; Lv, Haiyan; Yuan, Ling; Wang, Ying

    2016-01-01

    Flavonols as plant secondary metabolites with vital roles in plant development and defense against UV light, have been demonstrated to be the main bioactive components (BCs) in the genus Epimedium plants, several species of which are used as materials for Herba Epimedii, an important traditional Chinese medicine. The flavonol biosynthetic pathway genes had been already isolated from Epimedium sagittatum, but a R2R3-MYB transcription factor regulating the flavonol synthesis has not been functionally characterized so far in Epimedium plants. In this study, we isolated and characterized the R2R3-MYB transcription factor EsMYBF1 involved in regulation of the flavonol biosynthetic pathway from E. sagittatum. Sequence analysis indicated that EsMYBF1 belongs to the subgroup 7 of R2R3-MYB family which contains the flavonol-specific MYB regulators identified to date. Transient reporter assay showed that EsMYBF1 strongly activated the promoters of EsF3H (flavanone 3-hydroxylase) and EsFLS (flavonol synthase), but not the promoters of EsDFRs (dihydroflavonol 4-reductase) and EsANS (anthocyanidin synthase) in transiently transformed Nicotiana benthamiana leaves. Both yeast two-hybrid assay and transient reporter assay validated EsMYBF1 to be independent of EsTT8, or AtTT8 bHLH regulators of the flavonoid pathway as cofactors. Ectopic expression of EsMYBF1 in transgenic tobacco resulted in the increased flavonol content and the decreased anthocyanin content in flowers. Correspondingly, the structural genes involved in flavonol synthesis were upregulated in the EsMYBF1 overexpression lines, including NtCHS (chalcone synthase), NtCHI (chalcone isomerase), NtF3H and NtFLS, whereas the late biosynthetic genes of the anthocyanin pathway (NtDFR and NtANS) were remarkably downregulated, compared to the controls. These results suggest that EsMYBF1 is a flavonol-specific R2R3-MYB regulator, and involved in regulation of the biosynthesis of the flavonol-derived BCs in E. sagittatum. Thus

  18. A R2R3-MYB Transcription Factor Regulates the Flavonol Biosynthetic Pathway in a Traditional Chinese Medicinal Plant, Epimedium sagittatum

    PubMed Central

    Huang, Wenjun; Khaldun, A. B. M.; Chen, Jianjun; Zhang, Chanjuan; Lv, Haiyan; Yuan, Ling; Wang, Ying

    2016-01-01

    Flavonols as plant secondary metabolites with vital roles in plant development and defense against UV light, have been demonstrated to be the main bioactive components (BCs) in the genus Epimedium plants, several species of which are used as materials for Herba Epimedii, an important traditional Chinese medicine. The flavonol biosynthetic pathway genes had been already isolated from Epimedium sagittatum, but a R2R3-MYB transcription factor regulating the flavonol synthesis has not been functionally characterized so far in Epimedium plants. In this study, we isolated and characterized the R2R3-MYB transcription factor EsMYBF1 involved in regulation of the flavonol biosynthetic pathway from E. sagittatum. Sequence analysis indicated that EsMYBF1 belongs to the subgroup 7 of R2R3-MYB family which contains the flavonol-specific MYB regulators identified to date. Transient reporter assay showed that EsMYBF1 strongly activated the promoters of EsF3H (flavanone 3-hydroxylase) and EsFLS (flavonol synthase), but not the promoters of EsDFRs (dihydroflavonol 4-reductase) and EsANS (anthocyanidin synthase) in transiently transformed Nicotiana benthamiana leaves. Both yeast two-hybrid assay and transient reporter assay validated EsMYBF1 to be independent of EsTT8, or AtTT8 bHLH regulators of the flavonoid pathway as cofactors. Ectopic expression of EsMYBF1 in transgenic tobacco resulted in the increased flavonol content and the decreased anthocyanin content in flowers. Correspondingly, the structural genes involved in flavonol synthesis were upregulated in the EsMYBF1 overexpression lines, including NtCHS (chalcone synthase), NtCHI (chalcone isomerase), NtF3H and NtFLS, whereas the late biosynthetic genes of the anthocyanin pathway (NtDFR and NtANS) were remarkably downregulated, compared to the controls. These results suggest that EsMYBF1 is a flavonol-specific R2R3-MYB regulator, and involved in regulation of the biosynthesis of the flavonol-derived BCs in E. sagittatum. Thus

  19. MULTIPASS, a rice R2R3-type MYB transcription factor, regulates adaptive growth by integrating multiple hormonal pathways.

    PubMed

    Schmidt, Romy; Schippers, Jos H M; Mieulet, Delphine; Obata, Toshihiro; Fernie, Alisdair R; Guiderdoni, Emmanuel; Mueller-Roeber, Bernd

    2013-10-01

    Growth regulation is an important aspect of plant adaptation during environmental perturbations. Here, the role of MULTIPASS (OsMPS), an R2R3-type MYB transcription factor of rice, was explored. OsMPS is induced by salt stress and expressed in vegetative and reproductive tissues. Over-expression of OsMPS reduces growth under non-stress conditions, while knockdown plants display increased biomass. OsMPS expression is induced by abscisic acid and cytokinin, but is repressed by auxin, gibberellin and brassinolide. Growth retardation caused by OsMPS over-expression is partially restored by auxin application. Expression profiling revealed that OsMPS negatively regulates the expression of EXPANSIN (EXP) and cell-wall biosynthesis as well as phytohormone signaling genes. Furthermore, the expression of OsMPS-dependent genes is regulated by auxin, cytokinin and abscisic acid. Moreover, we show that OsMPS is a direct upstream regulator of OsEXPA4, OsEXPA8, OsEXPB2, OsEXPB3, OsEXPB6 and the endoglucanase genes OsGLU5 and OsGLU14. The multiple responses of OsMPS and its target genes to various hormones suggest an integrative function of OsMPS in the cross-talk between phytohormones and the environment to regulate adaptive growth.

  20. The F-box protein COI1 functions upstream of MYB305 to regulate primary carbohydrate metabolism in tobacco (Nicotiana tabacum L. cv. TN90)

    PubMed Central

    Zhang, Hongbo

    2014-01-01

    Jasmonate (JA) plays an important role in regulating plant male fertility and secondary metabolism, but its role in regulating primary metabolism remains unclear. The F-box protein CORONATINE INSENSITIVE 1 (COI1) is a critical component of the JA receptor, and mediates JA-signalling by targeting JASMONATE ZIM-domain (JAZ) proteins for proteasomal degradation in response to JA perception. Here, we found that RNA interference-mediated knockdown of NtCOI1 in tobacco (Nicotiana tabacum L. cv. TN90) recapitulated many previously observed phenotypes in coi1 mutants, including male sterility, JA insensitivity, and loss of floral anthocyanin production. It also affected starch metabolism in the pollen, anther wall, and floral nectary, leading to pollen abortion and loss of floral nectar. Transcript levels of genes encoding starch metabolism enzymes were significantly altered in the pollen, anther wall, and floral nectary of NtCOI1-silenced tobacco. Changes in leaf primary metabolism were also observed in the NtCOI1-silenced tobacco. The expression of NtMYB305, an orthologue of MYB305 previously identified as a flavonoid metabolic regulator in Antirrhinum majus flowers and as a floral-nectar regulator mediating starch synthesis in ornamental tobacco, was extremely downregulated in NtCOI1-silenced tobacco. These findings suggest that NtCOI1 functions upstream of NtMYB305 and plays a fundamental role in coordinating plant primary carbohydrate metabolism and correlative physiological processes. PMID:24604735

  1. miR-29 and miR-30 regulate B-Myb expression during cellular senescence

    PubMed Central

    Martinez, Ivan; Cazalla, Demian; Almstead, Laura L.; Steitz, Joan A.; DiMaio, Daniel

    2011-01-01

    Cellular senescence is a form of irreversible growth arrest and a major tumor suppressor mechanism. We show here that the miR-29 and miR-30 microRNA families are up-regulated during induced and replicative senescence and that up-regulation requires activation of the Rb pathway. Expression of a reporter construct containing the 3′UTR of the B-Myb oncogene is repressed during senescence, and repression is blocked by mutations in conserved miR-29 and miR-30 binding sites in the B-Myb 3′UTR. In proliferating cells, transfection of miR-29 and miR-30 represses a reporter construct containing the wild-type but not the mutant B-Myb 3′UTR, and repression of the mutant 3′UTR is reinstituted by compensatory mutations in miR-29 and miR-30 that restore binding to the mutant sites. miR-29 and miR-30 introduction also represses expression of endogenous B-Myb and inhibits cellular DNA synthesis. Finally, interference with miR-29 and miR-30 expression inhibits senescence. These findings demonstrate that miR-29 and miR-30 regulate B-Myb expression by binding to its 3′UTR and suggest that these microRNAs play an important role in Rb-driven cellular senescence. PMID:21187425

  2. NAC-MYB-based transcriptional regulation of secondary cell wall biosynthesis in land plants

    PubMed Central

    Nakano, Yoshimi; Yamaguchi, Masatoshi; Endo, Hitoshi; Rejab, Nur Ardiyana; Ohtani, Misato

    2015-01-01

    Plant cells biosynthesize primary cell walls (PCW) in all cells and produce secondary cell walls (SCWs) in specific cell types that conduct water and/or provide mechanical support, such as xylem vessels and fibers. The characteristic mechanical stiffness, chemical recalcitrance, and hydrophobic nature of SCWs result from the organization of SCW-specific biopolymers, i.e., highly ordered cellulose, hemicellulose, and lignin. Synthesis of these SCW-specific biopolymers requires SCW-specific enzymes that are regulated by SCW-specific transcription factors. In this review, we summarize our current knowledge of the transcriptional regulation of SCW formation in plant cells. Advances in research on SCW biosynthesis during the past decade have expanded our understanding of the transcriptional regulation of SCW formation, particularly the functions of the NAC and MYB transcription factors. Focusing on the NAC-MYB-based transcriptional network, we discuss the regulatory systems that evolved in land plants to modify the cell wall to serve as a key component of structures that conduct water and provide mechanical support. PMID:25999964

  3. AtMYB2 Regulates Whole Plant Senescence by Inhibiting Cytokinin-Mediated Branching at Late Stages of Development in Arabidopsis1[C][W][OA

    PubMed Central

    Guo, Yongfeng; Gan, Susheng

    2011-01-01

    Whole plant senescence of monocarpic plants consists of three major processes: arrest of shoot apical meristem, organ senescence, and permanent suppression of axillary buds. At early stages of development, axillary buds are inhibited by shoot apex-produced auxin, a mechanism known as apical dominance. How the buds are suppressed as an essential part of whole plant senescence, especially when the shoot apexes are senescent, is not clear. Here, we report an AtMYB2-regulated post apical dominance mechanism by which Arabidopsis (Arabidopsis thaliana) inhibits the outgrowth of axillary buds as part of the whole plant senescence program. AtMYB2 is expressed in the compressed basal internode region of Arabidopsis at late stages of development to suppress the production of cytokinins, the group of hormones that are required for axillary bud outgrowth. atmyb2 T-DNA insertion lines have enhanced expression of cytokinin-synthesizing isopentenyltransferases genes, contain higher levels of cytokinins, and display a bushy phenotype at late stages of development. As a result of the continuous generation of new shoots, atmyb2 plants have a prolonged life span. The AtMYB2 promoter-directed cytokinin oxidase 1 gene in the T-DNA insertion lines reduces the endogenous cytokinin levels and restores the bushy phenotype to the wild type. PMID:21543729

  4. Identification of Transcription Factors ZmMYB111 and ZmMYB148 Involved in Phenylpropanoid Metabolism

    PubMed Central

    Zhang, Junjie; Zhang, Shuangshuang; Li, Hui; Du, Hai; Huang, Huanhuan; Li, Yangping; Hu, Yufeng; Liu, Hanmei; Liu, Yinghong; Yu, Guowu; Huang, Yubi

    2016-01-01

    Maize is the leading crop worldwide in terms of both planting area and total yields, but environmental stresses cause significant losses in productivity. Phenylpropanoid compounds play an important role in plant stress resistance; however, the mechanism of their synthesis is not fully understood, especially in regard to the expression and regulation of key genes. Phenylalanine ammonia-lyase (PAL) is the first key enzyme involved in phenylpropanoid metabolism, and it has a significant effect on the synthesis of important phenylpropanoid compounds. According to the results of sequence alignments and functional prediction, we selected two conserved R2R3-MYB transcription factors as candidate genes for the regulation of phenylpropanoid metabolism. The two candidate R2R3-MYB genes, which we named ZmMYB111 and ZmMYB148, were cloned, and then their structural characteristics and phylogenetic placement were predicted and analyzed. In addition, a series of evaluations were performed, including expression profiles, subcellular localization, transcription activation, protein–DNA interaction, and transient expression in maize endosperm. Our results indicated that both ZmMYB111 and ZmMYB148 are indeed R2R3-MYB transcription factors and that they may play a regulatory role in PAL gene expression. PMID:26913047

  5. Alternative splicing of RNAs transcribed from the human c- myb gene

    SciTech Connect

    Shen-Ong, G.L.C.; Skurla, R.M. Jr.; Owens, J.D.; Mushinski, J.F. )

    1990-06-01

    An alternative splicing event in which a portion of the intron bounded by the vE6 and vE7 exons with v-{ital myb} homology is included as an additional 363-nucleotide coding exon (termed E6A or coding exon 9A) has been described for normal and tumor murine cells that express {ital myb}. The authors show that this alternative splicing event is conserved in human c-{ital myb} transcripts. In addition, another novel exon (termed E7A or coding exon 10A) is identified in human c-{ital myb} mRNAs expressed in normal and tumor cells. Although the {ital myb} protein isoform encoded by murine E6A-containing mRNA is larger than the major c-{ital myb} protein, the predicted products of both forms of human alternatively spliced {ital myb} transcripts are 3{prime}-truncated {ital myb} proteins that terminate in the alternative exons. These proteins are predicted to lack the same carboxy-terminal domains as the viral {ital myb} proteins encoded by avian myeloblastosis virus and E26 virus. The junction sequences that flank these exons closely resemble the consensus splice donor and splice acceptor sequences, yet the alternative transcripts are less abundant than is the major form of c-{ital myb} transcripts. The contribution that alternative splicing events in c-{ital myb} expression may make on c-{ital myb} function remains to be elucidated.

  6. MYB Elongation Is Regulated by the Nucleic Acid Binding of NFκB p50 to the Intronic Stem-Loop Region

    PubMed Central

    Malaterre, Jordane; Huiling, Xu; Sonza, Secondo; Cures, Alina; Purcell, Damian F. J.; Ramsland, Paul A.; Gerondakis, Steven; Gonda, Thomas J.; Ramsay, Robert G.

    2015-01-01

    MYB transcriptional elongation is regulated by an attenuator sequence within intron 1 that has been proposed to encode a RNA stem loop (SLR) followed by a polyU tract. We report that NFκBp50 can bind the SLR polyU RNA and promote MYB transcriptional elongation together with NFκBp65. We identified a conserved lysine-rich motif within the Rel homology domain (RHD) of NFκBp50, mutation of which abrogated the interaction of NFκBp50 with the SLR polyU and impaired NFκBp50 mediated MYB elongation. We observed that the TAR RNA-binding region of Tat is homologous to the NFκBp50 RHD lysine-rich motif, a finding consistent with HIV Tat acting as an effector of MYB transcriptional elongation in an SLR dependent manner. Furthermore, we identify the DNA binding activity of NFκBp50 as a key component required for the SLR polyU mediated regulation of MYB. Collectively these results suggest that the MYB SLR polyU provides a platform for proteins to regulate MYB and reveals novel nucleic acid binding properties of NFκBp50 required for MYB regulation. PMID:25853889

  7. MYB elongation is regulated by the nucleic acid binding of NFκB p50 to the intronic stem-loop region.

    PubMed

    Pereira, Lloyd A; Hugo, Honor J; Malaterre, Jordane; Huiling, Xu; Sonza, Secondo; Cures, Alina; Purcell, Damian F J; Ramsland, Paul A; Gerondakis, Steven; Gonda, Thomas J; Ramsay, Robert G

    2015-01-01

    MYB transcriptional elongation is regulated by an attenuator sequence within intron 1 that has been proposed to encode a RNA stem loop (SLR) followed by a polyU tract. We report that NFκBp50 can bind the SLR polyU RNA and promote MYB transcriptional elongation together with NFκBp65. We identified a conserved lysine-rich motif within the Rel homology domain (RHD) of NFκBp50, mutation of which abrogated the interaction of NFκBp50 with the SLR polyU and impaired NFκBp50 mediated MYB elongation. We observed that the TAR RNA-binding region of Tat is homologous to the NFκBp50 RHD lysine-rich motif, a finding consistent with HIV Tat acting as an effector of MYB transcriptional elongation in an SLR dependent manner. Furthermore, we identify the DNA binding activity of NFκBp50 as a key component required for the SLR polyU mediated regulation of MYB. Collectively these results suggest that the MYB SLR polyU provides a platform for proteins to regulate MYB and reveals novel nucleic acid binding properties of NFκBp50 required for MYB regulation.

  8. Integrated genome-wide chromatin occupancy and expression analyses identify key myeloid pro-differentiation transcription factors repressed by Myb.

    PubMed

    Zhao, Liang; Glazov, Evgeny A; Pattabiraman, Diwakar R; Al-Owaidi, Faisal; Zhang, Ping; Brown, Matthew A; Leo, Paul J; Gonda, Thomas J

    2011-06-01

    To gain insight into the mechanisms by which the Myb transcription factor controls normal hematopoiesis and particularly, how it contributes to leukemogenesis, we mapped the genome-wide occupancy of Myb by chromatin immunoprecipitation followed by massively parallel sequencing (ChIP-Seq) in ERMYB myeloid progenitor cells. By integrating the genome occupancy data with whole genome expression profiling data, we identified a Myb-regulated transcriptional program. Gene signatures for leukemia stem cells, normal hematopoietic stem/progenitor cells and myeloid development were overrepresented in 2368 Myb regulated genes. Of these, Myb bound directly near or within 793 genes. Myb directly activates some genes known critical in maintaining hematopoietic stem cells, such as Gfi1 and Cited2. Importantly, we also show that, despite being usually considered as a transactivator, Myb also functions to repress approximately half of its direct targets, including several key regulators of myeloid differentiation, such as Sfpi1 (also known as Pu.1), Runx1, Junb and Cebpb. Furthermore, our results demonstrate that interaction with p300, an established coactivator for Myb, is unexpectedly required for Myb-mediated transcriptional repression. We propose that the repression of the above mentioned key pro-differentiation factors may contribute essentially to Myb's ability to suppress differentiation and promote self-renewal, thus maintaining progenitor cells in an undifferentiated state and promoting leukemic transformation.

  9. Mapping a candidate gene (MdMYB10) for red flesh and foliage colour in apple

    PubMed Central

    Chagné, David; Carlisle, Charmaine M; Blond, Céline; Volz, Richard K; Whitworth, Claire J; Oraguzie, Nnadozie C; Crowhurst, Ross N; Allan, Andrew C; Espley, Richard V; Hellens, Roger P; Gardiner, Susan E

    2007-01-01

    Background Integrating plant genomics and classical breeding is a challenge for both plant breeders and molecular biologists. Marker-assisted selection (MAS) is a tool that can be used to accelerate the development of novel apple varieties such as cultivars that have fruit with anthocyanin through to the core. In addition, determining the inheritance of novel alleles, such as the one responsible for red flesh, adds to our understanding of allelic variation. Our goal was to map candidate anthocyanin biosynthetic and regulatory genes in a population segregating for the red flesh phenotypes. Results We have identified the Rni locus, a major genetic determinant of the red foliage and red colour in the core of apple fruit. In a population segregating for the red flesh and foliage phenotype we have determined the inheritance of the Rni locus and DNA polymorphisms of candidate anthocyanin biosynthetic and regulatory genes. Simple Sequence Repeats (SSRs) and Single Nucleotide Polymorphisms (SNPs) in the candidate genes were also located on an apple genetic map. We have shown that the MdMYB10 gene co-segregates with the Rni locus and is on Linkage Group (LG) 09 of the apple genome. Conclusion We have performed candidate gene mapping in a fruit tree crop and have provided genetic evidence that red colouration in the fruit core as well as red foliage are both controlled by a single locus named Rni. We have shown that the transcription factor MdMYB10 may be the gene underlying Rni as there were no recombinants between the marker for this gene and the red phenotype in a population of 516 individuals. Associating markers derived from candidate genes with a desirable phenotypic trait has demonstrated the application of genomic tools in a breeding programme of a horticultural crop species. PMID:17608951

  10. Intronic Sequence Regulates Sugar-Dependent Expression of Arabidopsis thaliana Production of Anthocyanin Pigment-1/MYB75

    PubMed Central

    Broeckling, Bettina E.; Watson, Ruth A.; Steinwand, Blaire; Bush, Daniel R.

    2016-01-01

    Sucrose-specific regulation of gene expression is recognized as an important signaling response, distinct from glucose, which serves to modulate plant growth, metabolism, and physiology. The Arabidopsis MYB transcription factor Production of Anthocyanin Pigment-1 (PAP1) plays a key role in anthocyanin biosynthesis and expression of PAP1 is known to be regulated by sucrose. Sucrose treatment of Arabidopsis seedlings led to a 20-fold induction of PAP1 transcript, which represented a 6-fold increase over levels in glucose-treated seedlings. The PAP1 promoter was not sufficient for conferring a sucrose response to a reporter gene and did not correctly report expression of PAP1 in plants. Although we identified 3 putative sucrose response elements in the PAP1 gene, none were found to be necessary for this response. Using deletion analysis, we identified a 90 bp sequence within intron 1 of PAP1 that is necessary for the sucrose response. This sequence was sufficient for conferring a sucrose response to a minimal promoter: luciferase reporter when present in multiple copies upstream of the promoter. This work lays the foundation for dissecting the sucrose signaling pathway of PAP1 and contributes to understanding the interplay between sucrose signaling, anthocyanin biosynthesis, and stress responses. PMID:27248141

  11. The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patterns of Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula[OPEN

    PubMed Central

    2015-01-01

    Accumulation of anthocyanins and proanthocyanidins (PAs) is limited to specific cell types and developmental stages, but little is known about how antagonistically acting transcriptional regulators work together to determine temporal and spatial patterning of pigmentation at the cellular level, especially for PAs. Here, we characterize MYB2, a transcriptional repressor regulating both anthocyanin and PA biosynthesis in the model legume Medicago truncatula. MYB2 was strongly upregulated by MYB5, a major regulator of PA biosynthesis in M. truncatula and a component of MYB-basic helix loop helix-WD40 (MBW) activator complexes. Overexpression of MYB2 abolished anthocyanin and PA accumulation in M. truncatula hairy roots and Arabidopsis thaliana seeds, respectively. Anthocyanin deposition was expanded in myb2 mutant seedlings and flowers accompanied by increased anthocyanin content. PA mainly accumulated in the epidermal layer derived from the outer integument in the M. truncatula seed coat, starting from the hilum area. The area of PA accumulation and ANTHOCYANIDIN REDUCTASE expression was expanded into the seed body at the early stage of seed development in the myb2 mutant. Genetic, biochemical, and cell biological evidence suggests that MYB2 functions as part of a multidimensional regulatory network to define the temporal and spatial pattern of anthocyanin and PA accumulation linked to developmental processes. PMID:26410301

  12. BZcon1, a SANT/Myb-Type Gene Involved in the Conidiation of Cochliobolus carbonum

    PubMed Central

    Zhang, Jun-xiang; Wu, Yi-xin; Ho, Honhing; Zhang, Hao; He, Peng-fei; He, Yue-qiu

    2014-01-01

    The fungal pathogen Cochliobolus carbonum (anamorph, Bipolaris zeicola) causes Northern Leaf Spot, leading to a ubiquitous and devastating foliar disease of corn in Yunnan Province, China. Asexual spores (conidia) play a major role in both epidemics and pathogenesis of Northern Leaf Spot, but the molecular mechanism of conidiation in C. carbonum has remained elusive. Here, using a map-based cloning strategy, we cloned a single dominant gene, designated as BZcon1 (for Bipolaris zeicola conidiation), which encodes a predicted unknown protein containing 402 amino acids, with two common conserved SANT/Myb domains in N-terminal. The BZcon1 knockout mutant completely lost the capability to produce conidiophores and conidia but displayed no effect on hyphal growth and sexual reproduction. The introduced BZcon1 gene fully complemented the BZcon1 null mutation, restoring the capability for sporulation. These data suggested that the BZcon1 gene is essential for the conidiation of C. carbonum. PMID:24898708

  13. Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera.

    PubMed

    Matus, José Tomás; Loyola, Rodrigo; Vega, Andrea; Peña-Neira, Alvaro; Bordeu, Edmundo; Arce-Johnson, Patricio; Alcalde, José Antonio

    2009-01-01

    Anthocyanins, flavan-3-ols, and flavonols are the three major classes of flavonoid compounds found in grape berry tissues. Several viticultural practices increase flavonoid content in the fruit, but the underlying genetic mechanisms responsible for these changes have not been completely deciphered. The impact of post-veraison sunlight exposure on anthocyanin and flavonol accumulation in grape berry skin and its relation to the expression of different transcriptional regulators known to be involved in flavonoid synthesis was studied. Treatments consisting of removing or moving aside the basal leaves which shade berry clusters were applied. Shading did not affect sugar accumulation or gene expression of HEXOSE TRANSPORTER 1, although in the leaf removal treatment, these events were retarded during the first weeks of ripening. Flavonols were the most drastically reduced flavonoids following shading and leaf removal treatments, related to the reduced expression of FLAVONOL SYNTHASE 4 and its putative transcriptional regulator MYB12. Anthocyanin accumulation and the expression of CHS2, LDOX, OMT, UFGT, MYBA1, and MYB5a genes were also affected. Other regulatory genes were less affected or not affected at all by these treatments. Non-transcriptional control mechanisms for flavonoid synthesis are also suggested, especially during the initial stages of ripening. Although berries from the leaf removal treatment received more light than shaded fruits, malvidin-3-glucoside and total flavonol content was reduced compared with the treatment without leaf removal. This work reveals that flavonol-related gene expression responds rapidly to field changes in light levels, as shown by the treatment in which shaded fruits were exposed to light in the late stages of ripening. Taken together, this study establishes MYB-specific responsiveness for the effect of sun exposure and sugar transport on flavonoid synthesis. PMID:19129169

  14. Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera

    PubMed Central

    Matus, José Tomás; Loyola, Rodrigo; Vega, Andrea; Peña-Neira, Alvaro; Bordeu, Edmundo; Arce-Johnson, Patricio; Alcalde, José Antonio

    2009-01-01

    Anthocyanins, flavan-3-ols, and flavonols are the three major classes of flavonoid compounds found in grape berry tissues. Several viticultural practices increase flavonoid content in the fruit, but the underlying genetic mechanisms responsible for these changes have not been completely deciphered. The impact of post-veraison sunlight exposure on anthocyanin and flavonol accumulation in grape berry skin and its relation to the expression of different transcriptional regulators known to be involved in flavonoid synthesis was studied. Treatments consisting of removing or moving aside the basal leaves which shade berry clusters were applied. Shading did not affect sugar accumulation or gene expression of HEXOSE TRANSPORTER 1, although in the leaf removal treatment, these events were retarded during the first weeks of ripening. Flavonols were the most drastically reduced flavonoids following shading and leaf removal treatments, related to the reduced expression of FLAVONOL SYNTHASE 4 and its putative transcriptional regulator MYB12. Anthocyanin accumulation and the expression of CHS2, LDOX, OMT, UFGT, MYBA1, and MYB5a genes were also affected. Other regulatory genes were less affected or not affected at all by these treatments. Non-transcriptional control mechanisms for flavonoid synthesis are also suggested, especially during the initial stages of ripening. Although berries from the leaf removal treatment received more light than shaded fruits, malvidin-3-glucoside and total flavonol content was reduced compared with the treatment without leaf removal. This work reveals that flavonol-related gene expression responds rapidly to field changes in light levels, as shown by the treatment in which shaded fruits were exposed to light in the late stages of ripening. Taken together, this study establishes MYB-specific responsiveness for the effect of sun exposure and sugar transport on flavonoid synthesis. PMID:19129169

  15. Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera.

    PubMed

    Matus, José Tomás; Loyola, Rodrigo; Vega, Andrea; Peña-Neira, Alvaro; Bordeu, Edmundo; Arce-Johnson, Patricio; Alcalde, José Antonio

    2009-01-01

    Anthocyanins, flavan-3-ols, and flavonols are the three major classes of flavonoid compounds found in grape berry tissues. Several viticultural practices increase flavonoid content in the fruit, but the underlying genetic mechanisms responsible for these changes have not been completely deciphered. The impact of post-veraison sunlight exposure on anthocyanin and flavonol accumulation in grape berry skin and its relation to the expression of different transcriptional regulators known to be involved in flavonoid synthesis was studied. Treatments consisting of removing or moving aside the basal leaves which shade berry clusters were applied. Shading did not affect sugar accumulation or gene expression of HEXOSE TRANSPORTER 1, although in the leaf removal treatment, these events were retarded during the first weeks of ripening. Flavonols were the most drastically reduced flavonoids following shading and leaf removal treatments, related to the reduced expression of FLAVONOL SYNTHASE 4 and its putative transcriptional regulator MYB12. Anthocyanin accumulation and the expression of CHS2, LDOX, OMT, UFGT, MYBA1, and MYB5a genes were also affected. Other regulatory genes were less affected or not affected at all by these treatments. Non-transcriptional control mechanisms for flavonoid synthesis are also suggested, especially during the initial stages of ripening. Although berries from the leaf removal treatment received more light than shaded fruits, malvidin-3-glucoside and total flavonol content was reduced compared with the treatment without leaf removal. This work reveals that flavonol-related gene expression responds rapidly to field changes in light levels, as shown by the treatment in which shaded fruits were exposed to light in the late stages of ripening. Taken together, this study establishes MYB-specific responsiveness for the effect of sun exposure and sugar transport on flavonoid synthesis.

  16. Characterization of the regulatory network of BoMYB2 in controlling anthocyanin biosynthesis in purple cauliflower.

    PubMed

    Chiu, Li-Wei; Li, Li

    2012-10-01

    Purple cauliflower (Brassica oleracea L. var. botrytis) Graffiti represents a unique mutant in conferring ectopic anthocyanin biosynthesis, which is caused by the tissue-specific activation of BoMYB2, an ortholog of Arabidopsis PAP2 or MYB113. To gain a better understanding of the regulatory network of anthocyanin biosynthesis, we investigated the interaction among cauliflower MYB-bHLH-WD40 network proteins and examined the interplay of BoMYB2 with various bHLH transcription factors in planta. Yeast two-hybrid studies revealed that cauliflower BoMYBs along with the other regulators formed the MYB-bHLH-WD40 complexes and BobHLH1 acted as a bridge between BoMYB and BoWD40-1 proteins. Different BoMYBs exhibited different binding activity to BobHLH1. Examination of the BoMYB2 transgenic lines in Arabidopsis bHLH mutant backgrounds demonstrated that TT8, EGL3, and GL3 were all involved in the BoMYB2-mediated anthocyanin biosynthesis. Expression of BoMYB2 in Arabidopsis caused up-regulation of AtTT8 and AtEGL3 as well as a subset of anthocyanin structural genes encoding flavonoid 3'-hydroxylase, dihydroflavonol 4-reductase, and leucoanthocyanidin dioxygenase. Taken together, our results show that MYB-bHLH-WD40 network transcription factors regulated the bHLH gene expression, which may represent a critical feature in the control of anthocyanin biosynthesis. BoMYB2 together with various BobHLHs specifically regulated the late anthocyanin biosynthetic pathway genes for anthocyanin biosynthesis. Our findings provide additional information for the complicated regulatory network of anthocyanin biosynthesis and the transcriptional regulation of transcription factors in vegetable crops.

  17. The Arabidopsis Transcription Factor MYB77 Modulates Auxin Signal Transduction[W

    PubMed Central

    Shin, Ryoung; Burch, Adrien Y.; Huppert, Kari A.; Tiwari, Shiv B.; Murphy, Angus S.; Guilfoyle, Tom J.; Schachtman, Daniel P.

    2007-01-01

    Auxin is a key plant hormone that regulates plant development, apical dominance, and growth-related tropisms, such as phototropism and gravitropism. In this study, we report a new Arabidopsis thaliana transcription factor, MYB77, that is involved in auxin response. In MYB77 knockout plants, we found that auxin-responsive gene expression was greatly attenuated. Lateral root density in the MYB77 knockout was lower than the wild type at low concentrations of indole-3-acetic acid (IAA) and also under low nutrient conditions. MYB77 interacts with auxin response factors (ARFs) in vitro through the C terminus (domains III and IV) of ARFs and the activation domain of MYB77. A synergistic genetic interaction was demonstrated between MYB77 and ARF7 that resulted in a strong reduction in lateral root numbers. Experiments with protoplasts confirmed that the coexpression of MYB77 and an ARF C terminus enhance reporter gene expression. R2R3 MYB transcription factors have not been previously implicated in regulating the expression of auxin-inducible genes. Also it was previously unknown that ARFs interact with proteins other than those in the Aux/IAA family via conserved domains. The interaction between MYB77 and ARFs defines a new type of combinatorial transcriptional control in plants. This newly defined transcription factor interaction is part of the plant cells' repertoire for modulating response to auxin, thereby controlling lateral root growth and development under changing environmental conditions. PMID:17675404

  18. Identification of genes in the phenylalanine metabolic pathway by ectopic expression of a MYB transcription factor in tomato fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Altering expression of transcription factors can be an effective means to coordinately modulate entire metabolic pathways in plants. It can also provide useful information concerning the identities of genes that constitute metabolic networks. Here, we used ectopic expression of a MYB transcription f...

  19. The oil palm VIRESCENS gene controls fruit colour and encodes a R2R3-MYB.

    PubMed

    Singh, Rajinder; Low, Eng-Ti Leslie; Ooi, Leslie Cheng-Li; Ong-Abdullah, Meilina; Nookiah, Rajanaidu; Ting, Ngoot-Chin; Marjuni, Marhalil; Chan, Pek-Lan; Ithnin, Maizura; Manaf, Mohd Arif Abdul; Nagappan, Jayanthi; Chan, Kuang-Lim; Rosli, Rozana; Halim, Mohd Amin; Azizi, Norazah; Budiman, Muhammad A; Lakey, Nathan; Bacher, Blaire; Van Brunt, Andrew; Wang, Chunyan; Hogan, Michael; He, Dong; MacDonald, Jill D; Smith, Steven W; Ordway, Jared M; Martienssen, Robert A; Sambanthamurthi, Ravigadevi

    2014-01-01

    Oil palm, a plantation crop of major economic importance in Southeast Asia, is the predominant source of edible oil worldwide. We report the identification of the virescens (VIR) gene, which controls fruit exocarp colour and is an indicator of ripeness. VIR is a R2R3-MYB transcription factor with homology to Lilium LhMYB12 and similarity to Arabidopsis production of anthocyanin pigment1 (PAP1). We identify five independent mutant alleles of VIR in over 400 accessions from sub-Saharan Africa that account for the dominant-negative virescens phenotype. Each mutation results in premature termination of the carboxy-terminal domain of VIR, resembling McClintock's C1-I allele in maize. The abundance of alleles likely reflects cultural practices, by which fruits were venerated for magical and medicinal properties. The identification of VIR will allow selection of the trait at the seed or early-nursery stage, 3-6 years before fruits are produced, greatly advancing introgression into elite breeding material. PMID:24978855

  20. The oil palm VIRESCENS gene controls fruit colour and encodes a R2R3-MYB

    PubMed Central

    Singh, Rajinder; Low, Eng-Ti Leslie; Ooi, Leslie Cheng-Li; Ong-Abdullah, Meilina; Nookiah, Rajanaidu; Ting, Ngoot-Chin; Marjuni, Marhalil; Chan, Pek-Lan; Ithnin, Maizura; Manaf, Mohd Arif Abdul; Nagappan, Jayanthi; Chan, Kuang-Lim; Rosli, Rozana; Halim, Mohd Amin; Azizi, Norazah; Budiman, Muhammad A.; Lakey, Nathan; Bacher, Blaire; Van Brunt, Andrew; Wang, Chunyan; Hogan, Michael; He, Dong; MacDonald, Jill D.; Smith, Steven W.; Ordway, Jared M.; Martienssen, Robert A.; Sambanthamurthi, Ravigadevi

    2014-01-01

    Oil palm, a plantation crop of major economic importance in Southeast Asia, is the predominant source of edible oil worldwide. We report the identification of the VIRESCENS (VIR) gene, which controls fruit exocarp colour and is an indicator of ripeness. VIR is a R2R3-MYB transcription factor with homology to Lilium LhMYB12 and similarity to Arabidopsis PRODUCTION OF ANTHOCYANIN PIGMENT1 (PAP1). We identify five independent mutant alleles of VIR in over 400 accessions from sub-Saharan Africa that account for the dominant-negative virescens phenotype. Each mutation results in premature termination of the carboxy-terminal domain of VIR, resembling McClintock’s C1-I allele in maize. The abundance of alleles likely reflects cultural practices, by which fruits were venerated for magical and medicinal properties. The identification of VIR will allow selection of the trait at the seed or early-nursery stage, 3-6 years before fruits are produced, greatly advancing introgression into elite breeding material. PMID:24978855

  1. The WEREWOLF MYB protein directly regulates CAPRICE transcription during cell fate specification in the Arabidopsis root epidermis.

    PubMed

    Ryu, Kook Hui; Kang, Yeon Hee; Park, Young-hwan; Hwang, Ildoo; Schiefelbein, John; Lee, Myeong Min

    2005-11-01

    The Arabidopsis root epidermis is composed of two types of cells, hair cells and non-hair cells, and their fate is determined in a position-dependent manner. WEREWOLF (WER), a R2R3 MYB protein, has been shown genetically to function as a master regulator to control both of the epidermal cell fates. To directly test the proposed role of WER in this system, we examined its subcellular localization and defined its transcriptional activation properties. We show that a WER-GFP fusion protein is functional and accumulates in the nucleus of the N-position cells in the Arabidopsis root epidermis, as expected for a transcriptional regulator. We also find that a modified WER protein with a strong activation domain (WER-VP16) promotes the formation of both epidermal cell types, supporting the view that WER specifies both cell fates. In addition, we used the glucocorticoid receptor (GR) inducible system to show that CPC transcription is regulated directly by WER. Using EMSA, we found two WER-binding sites (WBSs; WBSI and WBSII) in the CPC promoter. WER-WBSI binding was confirmed in vivo using the yeast one-hybrid assay. Binding between the WER protein and both WBSs (WBSI and WBSII), and the importance of the two WBSs in CPC promoter activity were confirmed in Arabidopsis. These results provide experimental support for the proposed role of WER as an activator of gene transcription during the specification of both epidermal cell fates.

  2. OsMYB103L, an R2R3-MYB transcription factor, influences leaf rolling and mechanical strength in rice (Oryza sativa L.)

    PubMed Central

    2014-01-01

    Background The shape of grass leaves possesses great value in both agronomy and developmental biology research. Leaf rolling is one of the important traits in rice (Oryza sativa L.) breeding. MYB transcription factors are one of the largest gene families and have important roles in plant development, metabolism and stress responses. However, little is known about their functions in rice. Results In this study, we report the functional characterization of a rice gene, OsMYB103L, which encodes an R2R3-MYB transcription factor. OsMYB103L was localized in the nucleus with transactivation activity. Overexpression of OsMYB103L in rice resulted in a rolled leaf phenotype. Further analyses showed that expression levels of several cellulose synthase genes (CESAs) were significantly increased, as was the cellulose content in OsMYB103L overexpressing lines. Knockdown of OsMYB103L by RNA interference led to a decreased level of cellulose content and reduced mechanical strength in leaves. Meanwhile, the expression levels of several CESA genes were decreased in these knockdown lines. Conclusions These findings suggest that OsMYB103L may target CESA genes for regulation of cellulose synthesis and could potentially be engineered for desirable leaf shape and mechanical strength in rice. PMID:24906444

  3. Overexpression of MYB drives proliferation of CYLD-defective cylindroma cells.

    PubMed

    Rajan, Neil; Andersson, Mattias K; Sinclair, Naomi; Fehr, André; Hodgson, Kirsty; Lord, Christopher J; Kazakov, Dmitry V; Vanecek, Tomas; Ashworth, Alan; Stenman, Göran

    2016-06-01

    Cutaneous cylindroma is an adnexal tumour with apocrine differentiation. A predisposition to multiple cylindromas is seen in patients with Brooke-Spiegler syndrome, who carry germline mutations in the tumour suppressor gene CYLD. Previous studies of inherited cylindromas have highlighted the frequent presence of bi-allelic truncating CYLD mutations as a recurrent driver mutation. We have previously shown that sporadic cylindromas express either MYB-NFIB fusion transcripts or show evidence of MYB activation in the absence of such fusions. Here, we investigated inherited cylindromas from several families with germline CYLD mutations for the presence of MYB activation. Strikingly, none of the inherited CYLD-defective (n = 23) tumours expressed MYB-NFIB fusion transcripts. However, MYB expression was increased in the majority of tumours (69%) and global gene expression analysis revealed that well-established MYB target genes were up-regulated in CYLD-defective tumours. Moreover, knock-down of MYB expression caused a significant reduction in cylindroma cell proliferation, suggesting that MYB is also a key player and oncogenic driver in inherited cylindromas. Taken together, our findings suggest molecular heterogeneity in the pathogenesis of sporadic and inherited cutaneous cylindromas, with convergence on MYB activation. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. PMID:26969893

  4. The beet Y locus encodes an anthocyanin MYB-like protein that activates the betalain red pigment pathway.

    PubMed

    Hatlestad, Gregory J; Akhavan, Neda A; Sunnadeniya, Rasika M; Elam, Lee; Cargile, Scott; Hembd, Austin; Gonzalez, Antonio; McGrath, J Mitchell; Lloyd, Alan M

    2015-01-01

    Nearly all flowering plants produce red/violet anthocyanin pigments. Caryophyllales is the only order containing families that replace anthocyanins with unrelated red and yellow betalain pigments. Close biological correlation of pigmentation patterns suggested that betalains might be regulated by a conserved anthocyanin-regulating transcription factor complex consisting of a MYB, a bHLH and a WD repeat-containing protein (the MBW complex). Here we show that a previously uncharacterized anthocyanin MYB-like protein, Beta vulgaris MYB1 (BvMYB1), regulates the betalain pathway in beets. Silencing BvMYB1 downregulates betalain biosynthetic genes and pigmentation, and overexpressing BvMYB1 upregulates them. However, unlike anthocyanin MYBs, BvMYB1 will not interact with bHLH members of heterologous anthocyanin MBW complexes because of identified nonconserved residues. BvMYB1 resides at the historic beet pigment-patterning locus, Y, required for red-fleshed beets. We show that Y and y express different levels of BvMYB1 transcripts. The co-option of a transcription factor regulating anthocyanin biosynthesis would be an important evolutionary event allowing betalains to largely functionally replace anthocyanins. PMID:25436858

  5. The beet Y locus encodes an anthocyanin MYB-like protein that activates the betalain red pigment pathway.

    PubMed

    Hatlestad, Gregory J; Akhavan, Neda A; Sunnadeniya, Rasika M; Elam, Lee; Cargile, Scott; Hembd, Austin; Gonzalez, Antonio; McGrath, J Mitchell; Lloyd, Alan M

    2015-01-01

    Nearly all flowering plants produce red/violet anthocyanin pigments. Caryophyllales is the only order containing families that replace anthocyanins with unrelated red and yellow betalain pigments. Close biological correlation of pigmentation patterns suggested that betalains might be regulated by a conserved anthocyanin-regulating transcription factor complex consisting of a MYB, a bHLH and a WD repeat-containing protein (the MBW complex). Here we show that a previously uncharacterized anthocyanin MYB-like protein, Beta vulgaris MYB1 (BvMYB1), regulates the betalain pathway in beets. Silencing BvMYB1 downregulates betalain biosynthetic genes and pigmentation, and overexpressing BvMYB1 upregulates them. However, unlike anthocyanin MYBs, BvMYB1 will not interact with bHLH members of heterologous anthocyanin MBW complexes because of identified nonconserved residues. BvMYB1 resides at the historic beet pigment-patterning locus, Y, required for red-fleshed beets. We show that Y and y express different levels of BvMYB1 transcripts. The co-option of a transcription factor regulating anthocyanin biosynthesis would be an important evolutionary event allowing betalains to largely functionally replace anthocyanins.

  6. PtoMYB92 is a Transcriptional Activator of the Lignin Biosynthetic Pathway During Secondary Cell Wall Formation in Populus tomentosa.

    PubMed

    Li, Chaofeng; Wang, Xianqiang; Ran, Lingyu; Tian, Qiaoyan; Fan, Di; Luo, Keming

    2015-12-01

    Wood is the most abundant biomass in perennial woody plants and is mainly made up of secondary cell wall. R2R3-MYB transcription factors are important regulators of secondary wall biosynthesis in plants. In this study, we describe the identification and characterization of a poplar MYB transcription factor PtoMYB92, a homolog of Arabidopsis MYB42 and MYB85, which is involved in the regulation of secondary cell wall biosynthesis. PtoMYB92 is specifically expressed in xylem tissue in poplar. Subcellular localization and transcriptional activation analysis suggest that PtoMYB92 is a nuclear-localized transcriptional activator. Overexpression of PtoMYB92 in poplar resulted in an increase in secondary cell wall thickness in stems and ectopic deposition of lignin in leaves. Quantitative real-time PCR showed that PtoMYB92 specifically activated the expression of lignin biosynthetic genes. Furthermore, transient expression assays using a β-glucuronidase (GUS) reporter gene revealed that PtoMYB92 is an activator in the lignin biosynthetic pathway during secondary cell wall formation. Taken together, our results suggest that PtoMYB92 is involved in the regulation of secondary cell wall formation in poplar by controlling the biosynthesis of monolignols.

  7. The Arabidopsis Myb transcription factor MTF1 is a unidirectional regulator of susceptibility to Agrobacterium.

    PubMed

    Sardesai, Nagesh; Laluk, Kristin; Mengiste, Tesfaye; Gelvin, Stanton

    2014-04-30

    We recently described the Arabidopsis Myb transcription factor MTF1 that negatively regulates plant susceptibility to Agrobacterium-mediated transformation. Roots of mtf1 mutant plants show increased susceptibility to several Agrobacterium strains, and complementing the mutants with a MTF1 cDNA decreases transformation susceptibility to wild-type levels. Here, we show that overexpression of MTF1 in a wild-type Arabidopsis background does not result in altered transformation susceptibility. However, MTF1 overexpressing plants show increased root length and larger and darker leaves, indicating that MTF1 plays a role in plant growth and development. MTF1 decreases Arabidopsis root susceptibility specifically to Agrobacterium but plant responses to the pathogens Alternaria brassicicola or Pseudomonas syringae pv Tomato were not altered. However, the homozygous MTF1 mutant mtf1-4 is resistant to Botrytis cinerea strain BO5-10 and is regulated through the ethylene signaling pathway mediated by upregulation of the AP2/ERF transcription factor ORA59. PMID:24785741

  8. Opposing Control by Transcription Factors MYB61 and MYB3 Increases Freezing Tolerance by Relieving C-Repeat Binding Factor Suppression1[OPEN

    PubMed Central

    Zhang, Yunqin; Miao, Zhenyan; Xie, Can; Meng, Xiangzhao; Deng, Jie; Mysore, Kirankumar S.; Frugier, Florian; Wang, Tao

    2016-01-01

    Cold acclimation is an important process by which plants respond to low temperature and enhance their winter hardiness. C-REPEAT BINDING FACTOR1 (CBF1), CBF2, and CBF3 genes were shown previously to participate in cold acclimation in Medicago truncatula. In addition, MtCBF4 is transcriptionally induced by salt, drought, and cold stresses. We show here that MtCBF4, shown previously to enhance drought and salt tolerance, also positively regulates cold acclimation and freezing tolerance. To identify molecular factors acting upstream and downstream of the MtCBF4 transcription factor (TF) in cold responses, we first identified genes that are differentially regulated upon MtCBF4 overexpression using RNAseq Digital Gene Expression Profiling. Among these, we showed that MtCBF4 directly activates the transcription of the COLD ACCLIMATION SPECIFIC15 (MtCAS15) gene. To gain insights into how MtCBF4 is transcriptionally regulated in response to cold, an R2R3-MYB TF, MtMYB3, was identified based on a yeast one-hybrid screen as binding directly to MYB cis-elements in the MtCBF4 promoter, leading to the inhibition of MtCBF4 expression. In addition, another MYB TF, MtMYB61, identified as an interactor of MtMYB3, can relieve the inhibitory effect of MtMYB3 on MtCBF4 transcription. This study, therefore, supports a model describing how MtCBF4 is regulated by antagonistic MtMYB3/MtMYB61 TFs, leading to the up-regulation of downstream targets such as MtCAS15 acting in cold acclimation in M. truncatula. PMID:27578551

  9. Genome-wide analysis of the MYB transcription factor superfamily in soybean

    PubMed Central

    2012-01-01

    Background The MYB superfamily constitutes one of the most abundant groups of transcription factors described in plants. Nevertheless, their functions appear to be highly diverse and remain rather unclear. To date, no genome-wide characterization of this gene family has been conducted in a legume species. Here we report the first genome-wide analysis of the whole MYB superfamily in a legume species, soybean (Glycine max), including the gene structures, phylogeny, chromosome locations, conserved motifs, and expression patterns, as well as a comparative genomic analysis with Arabidopsis. Results A total of 244 R2R3-MYB genes were identified and further classified into 48 subfamilies based on a phylogenetic comparative analysis with their putative orthologs, showed both gene loss and duplication events. The phylogenetic analysis showed that most characterized MYB genes with similar functions are clustered in the same subfamily, together with the identification of orthologs by synteny analysis, functional conservation among subgroups of MYB genes was strongly indicated. The phylogenetic relationships of each subgroup of MYB genes were well supported by the highly conserved intron/exon structures and motifs outside the MYB domain. Synonymous nucleotide substitution (dN/dS) analysis showed that the soybean MYB DNA-binding domain is under strong negative selection. The chromosome distribution pattern strongly indicated that genome-wide segmental and tandem duplication contribute to the expansion of soybean MYB genes. In addition, we found that ~ 4% of soybean R2R3-MYB genes had undergone alternative splicing events, producing a variety of transcripts from a single gene, which illustrated the extremely high complexity of transcriptome regulation. Comparative expression profile analysis of R2R3-MYB genes in soybean and Arabidopsis revealed that MYB genes play conserved and various roles in plants, which is indicative of a divergence in function. Conclusions In this

  10. Alleles of the maize P gene with distinct tissue specificities encode Myb-homologous proteins with C-terminal replacements.

    PubMed Central

    Chopra, S; Athma, P; Peterson, T

    1996-01-01

    The maize P gene is a transcriptional regulator of genes encoding enzymes for flavonoid biosynthesis in the pathway leading to the production of a red phlobaphene pigment. Multiple alleles of the P gene confer distinct patterns of pigmentation to specific floral organs, such as the kernel pericarp and cob tissues. To determine the basis of allele-specific pigmentation, we have characterized the gene products and transcript accumulation patterns of the P-wr allele, which specifies colorless pericarps and red cob tissues. RNA transcripts of P-wr are present in colorless pericarps as well as in the colored cob tissues; however, the expression of P-wr in pericarp does not induce the accumulation of transcripts from the C2 and A1 genes, which encode enzymes for flavonoid pigment biosynthesis. The coding sequences of P-wr were compared with the P-rr allele, which specifies red pericarp and red cob. The P-wr and P-rr cDNA sequences are very similar in their 5' regions. There are only two nucleotide changes that result in amino acid differences; both are outside of the Myb-homologous DNA binding domain. In contrast, the 3' coding region of P-rr is replaced by a unique 210-bp sequence in P-wr. The predicted P-wr protein has a C-terminal sequence resembling a cysteine-containing metal binding domain that is not present in the P-rr protein. These results indicate that the differential pericarp pigmentation specified by the P-rr and P-wr alleles does not result from an absence of P-wr transcripts in pericarps. Rather, the allele-specific patterns of P-rr and P-wr pigmentation may be associated with structural differences in the proteins encoded by each allele. PMID:8768374

  11. Genome-wide analysis of citrus R2R3MYB genes and their spatiotemporal expression under stresses and hormone treatments.

    PubMed

    Xie, Rangjin; Li, Yongjie; He, Shaolan; Zheng, Yongqiang; Yi, Shilai; Lv, Qiang; Deng, Lie

    2014-01-01

    The R2R3MYB proteins represent one of the largest families of transcription factors, which play important roles in plant growth and development. Although genome-wide analysis of this family has been conducted in many species, little is known about R2R3MYB genes in citrus, In this study, 101 R2R3MYB genes has been identified in the citrus (Citrus sinesis and Citrus clementina) genomes, which are almost equal to the number of rice. Phylogenetic analysis revealed that they could be subdivided into 21 subgroups. The evolutionary relationships and the intro-exon organizations were also analyzed, revealing strong gene conservation but also the expansions of particular functional genes during the plant evolution. Tissue-specific expression profiles showed that 95 citrus R2R3MYB genes were expressed in at least one tissue and the other 6 genes showed very low expression in all tissues tested, suggesting that citrus R2R3MYB genes play important roles in the development of all citrus organs. The transcript abundance level analysis during abiotic conditions (NaCl, abscisic acid, jasmonic acid, drought and low temperature) identified a group of R2R3MYB genes that responded to one or multiple treatments, which showed a promising for improving citrus adaptation to stresses. Our results provided an essential foundation for the future selection of the citrus R2R3MYB genes for cloning and functional dissection with an aim of uncovering their roles in citrus growth and development.

  12. Genome-Wide Analysis of Citrus R2R3MYB Genes and Their Spatiotemporal Expression under Stresses and Hormone Treatments

    PubMed Central

    He, Shaolan; Zheng, Yongqiang; Yi, Shilai; Lv, Qiang; Deng, Lie

    2014-01-01

    The R2R3MYB proteins represent one of the largest families of transcription factors, which play important roles in plant growth and development. Although genome-wide analysis of this family has been conducted in many species, little is known about R2R3MYB genes in citrus, In this study, 101 R2R3MYB genes has been identified in the citrus (Citrus sinesis and Citrus clementina) genomes, which are almost equal to the number of rice. Phylogenetic analysis revealed that they could be subdivided into 21 subgroups. The evolutionary relationships and the intro-exon organizations were also analyzed, revealing strong gene conservation but also the expansions of particular functional genes during the plant evolution. Tissue-specific expression profiles showed that 95 citrus R2R3MYB genes were expressed in at least one tissue and the other 6 genes showed very low expression in all tissues tested, suggesting that citrus R2R3MYB genes play important roles in the development of all citrus organs. The transcript abundance level analysis during abiotic conditions (NaCl, abscisic acid, jasmonic acid, drought and low temperature) identified a group of R2R3MYB genes that responded to one or multiple treatments, which showed a promising for improving citrus adaptation to stresses. Our results provided an essential foundation for the future selection of the citrus R2R3MYB genes for cloning and functional dissection with an aim of uncovering their roles in citrus growth and development. PMID:25473954

  13. Genome-wide analysis of citrus R2R3MYB genes and their spatiotemporal expression under stresses and hormone treatments.

    PubMed

    Xie, Rangjin; Li, Yongjie; He, Shaolan; Zheng, Yongqiang; Yi, Shilai; Lv, Qiang; Deng, Lie

    2014-01-01

    The R2R3MYB proteins represent one of the largest families of transcription factors, which play important roles in plant growth and development. Although genome-wide analysis of this family has been conducted in many species, little is known about R2R3MYB genes in citrus, In this study, 101 R2R3MYB genes has been identified in the citrus (Citrus sinesis and Citrus clementina) genomes, which are almost equal to the number of rice. Phylogenetic analysis revealed that they could be subdivided into 21 subgroups. The evolutionary relationships and the intro-exon organizations were also analyzed, revealing strong gene conservation but also the expansions of particular functional genes during the plant evolution. Tissue-specific expression profiles showed that 95 citrus R2R3MYB genes were expressed in at least one tissue and the other 6 genes showed very low expression in all tissues tested, suggesting that citrus R2R3MYB genes play important roles in the development of all citrus organs. The transcript abundance level analysis during abiotic conditions (NaCl, abscisic acid, jasmonic acid, drought and low temperature) identified a group of R2R3MYB genes that responded to one or multiple treatments, which showed a promising for improving citrus adaptation to stresses. Our results provided an essential foundation for the future selection of the citrus R2R3MYB genes for cloning and functional dissection with an aim of uncovering their roles in citrus growth and development. PMID:25473954

  14. Analysis of the grape MYB R2R3 subfamily reveals expanded wine quality-related clades and conserved gene structure organization across Vitis and Arabidopsis genomes

    PubMed Central

    Matus, José Tomás; Aquea, Felipe; Arce-Johnson, Patricio

    2008-01-01

    Background The MYB superfamily constitutes the most abundant group of transcription factors described in plants. Members control processes such as epidermal cell differentiation, stomatal aperture, flavonoid synthesis, cold and drought tolerance and pathogen resistance. No genome-wide characterization of this family has been conducted in a woody species such as grapevine. In addition, previous analysis of the recently released grape genome sequence suggested expansion events of several gene families involved in wine quality. Results We describe and classify 108 members of the grape R2R3 MYB gene subfamily in terms of their genomic gene structures and similarity to their putative Arabidopsis thaliana orthologues. Seven gene models were derived and analyzed in terms of gene expression and their DNA binding domain structures. Despite low overall sequence homology in the C-terminus of all proteins, even in those with similar functions across Arabidopsis and Vitis, highly conserved motif sequences and exon lengths were found. The grape epidermal cell fate clade is expanded when compared with the Arabidopsis and rice MYB subfamilies. Two anthocyanin MYBA related clusters were identified in chromosomes 2 and 14, one of which includes the previously described grape colour locus. Tannin related loci were also detected with eight candidate homologues in chromosomes 4, 9 and 11. Conclusion This genome wide transcription factor analysis in Vitis suggests that clade-specific grape R2R3 MYB genes are expanded while other MYB genes could be well conserved compared to Arabidopsis. MYB gene abundance, homology and orientation within particular loci also suggests that expanded MYB clades conferring quality attributes of grapes and wines, such as colour and astringency, could possess redundant, overlapping and cooperative functions. PMID:18647406

  15. Disruption of B-myb in DT40 cells reveals novel function for B-Myb in the response to DNA-damage.

    PubMed

    Ahlbory, Dörthe; Appl, Hartmut; Lang, Detlef; Klempnauer, Karl-Heinz

    2005-11-01

    B-Myb is a highly conserved vertebrate member of the Myb transcription factor family, which is expressed in virtually all proliferating cells. A large body of evidence suggests that B-Myb plays an important role in cell cycle regulation; however, the exact nature of its function has not yet been clarified. We have used gene targeting in chicken DT40 cells, a cell line exhibiting very high rates of homologous recombination, to create cells expressing endogenous B-myb in a doxycyclin-dependent manner. We find that the cells proliferate well in the absence of B-Myb, suggesting that B-Myb is not essential for cell proliferation per se. However, cells lacking B-Myb are more sensitive to DNA-damage induced by UV-irradiation and alkylation. Our work provides the first direct evidence for a novel function of B-Myb in the response to DNA-damage. The cells described here should be a useful model to characterize this function in more detail. PMID:16170378

  16. Regulation of nuclear translocation of the Myb1 transcription factor by TvCyclophilin 1 in the protozoan parasite Trichomonas vaginalis.

    PubMed

    Hsu, Hong-Ming; Chu, Chien-Hsin; Wang, Ya-Ting; Lee, Yu; Wei, Shu-Yi; Liu, Hsing-Wei; Ong, Shiou-Jeng; Chen, Chinpan; Tai, Jung-Hsiang

    2014-07-01

    In Trichomonas vaginalis, a Myb1 protein was previously demonstrated to repress transcription of an iron-inducible ap65-1 gene. In this study, a human cyclophilin A homologue, TvCyclophilin 1 (TvCyP1), was identified as a Myb1-binding protein using a bacterial two-hybrid library screening system. The recombinant TvCyP1 exhibited typical peptidyl-prolyl isomerase activity with kcat/Km of ∼7.1 μm(-1) s(-1). In a pulldown assay, the His-tagged Myb1 interacted with a GST-TvCyP1 fusion protein, which had an enzymatic proficiency half that of recombinant TvCyP1. Both the enzymatic proficiency of GST-TvCyP1 and its binding to His-Myb1 were eliminated by mutation of Arg(63) in the catalytic motif or inhibited by cyclosporin A. TvCyP1 was primarily localized to the hydrogenosomes by immunofluorescence assay, but it was also co-purified with Myb1 in certain vesicle fractions from differential and gradient centrifugations. Transgenic cells overexpressing HA-TvCyP1 had a higher level of nuclear Myb1 but a much lower level of Myb1 associated with the vesicles than control and those overexpressing HA-TvCyP1(R63A). Myb1 was detected at a much higher level in the HA-TvCyP1 protein complex than in the HA-TvCyP1(R63A) protein complex immunoprecipitated from P15 and P100, but not S100, fractions of postnuclear lysates. A TvCyP1-binding motif, (105)YGPKWNK(111), was identified in Myb1 in which Gly(106) and Pro(107) were essential for its binding to TvCyP1. Mutation of Gly(106) and Pro(107), respectively, in HA-Myb1 resulted in cytoplasmic retention and elevated nuclear translocation of the overexpressed protein. These results suggest that TvCyP1 may induce the release of Myb1 that is restrained to certain cytoplasmic vesicles prior to its nuclear translocation.

  17. Functional diversification of the potato R2R3 MYB anthocyanin activators AN1, MYBA1, and MYB113 and their interaction with basic helix-loop-helix cofactors.

    PubMed

    Liu, Yuhui; Lin-Wang, Kui; Espley, Richard V; Wang, Li; Yang, Hongyu; Yu, Bin; Dare, Andrew; Varkonyi-Gasic, Erika; Wang, Jing; Zhang, Junlian; Wang, Di; Allan, Andrew C

    2016-04-01

    In potato (Solanum tuberosum L.), R2R3 MYBs are involved in the regulation of anthocyanin biosynthesis. We examined sequences of these MYBs in cultivated potatoes, which are more complex than diploid potato due to ploidy and heterozygosity. We found amino acid variants in the C-terminus of the MYB StAN1, termed R0, R1, and R3, due to the presence of a repeated 10-amino acid motif. These variant MYBs showed some expression in both white and pigmented tubers. We found several new alleles or gene family members of R2R3 MYBs,StMYBA1 and StMYB113, which were also expressed in white potato tubers. From functional analysis in tobacco, we showed that the presence of a C-terminal 10-amino acid motif is optimal for activating anthocyanin accumulation. Engineering a motif back into a MYB lacking this sequence enhanced its activating ability. Versions of StMYBA1 and StMYB113 can also activate anthocyanin accumulation in tobacco leaves, with the exception of StMYB113-3, which has a partial R2R3 domain. We isolated five family members of potato StbHLH1, and one StJAF13, to test their ability to interact with MYB variants. The results showed that two alleles of StbHLH1 from white skin and red skin are non-functional, while three other StbHLH1s have different co-regulating abilities, and need to be activated by StJAF13. Combined with expression analysis in potato tuber, results suggest that StbHLH1 and StJAF13a re key co-regulators of anthocyanin biosynthesis, while the transcripts of MYB variants StAN1,StMYBA1, and StMYB113 are well expressed, even in the absence of pigmentation.

  18. Functional diversification of the potato R2R3 MYB anthocyanin activators AN1, MYBA1, and MYB113 and their interaction with basic helix-loop-helix cofactors

    PubMed Central

    Liu, Yuhui; Lin-Wang, Kui; Espley, Richard V.; Wang, Li; Yang, Hongyu; Yu, Bin; Dare, Andrew; Varkonyi-Gasic, Erika; Wang, Jing; Zhang, Junlian; Wang, Di; Allan, Andrew C.

    2016-01-01

    In potato (Solanum tuberosum L.), R2R3 MYBs are involved in the regulation of anthocyanin biosynthesis. We examined sequences of these MYBs in cultivated potatoes, which are more complex than diploid potato due to ploidy and heterozygosity. We found amino acid variants in the C-terminus of the MYB StAN1, termed R0, R1, and R3, due to the presence of a repeated 10-amino acid motif. These variant MYBs showed some expression in both white and pigmented tubers. We found several new alleles or gene family members of R2R3 MYBs, StMYBA1 and StMYB113, which were also expressed in white potato tubers. From functional analysis in tobacco, we showed that the presence of a C-terminal 10-amino acid motif is optimal for activating anthocyanin accumulation. Engineering a motif back into a MYB lacking this sequence enhanced its activating ability. Versions of StMYBA1 and StMYB113 can also activate anthocyanin accumulation in tobacco leaves, with the exception of StMYB113-3, which has a partial R2R3 domain. We isolated five family members of potato StbHLH1, and one StJAF13, to test their ability to interact with MYB variants. The results showed that two alleles of StbHLH1 from white skin and red skin are non-functional, while three other StbHLH1s have different co-regulating abilities, and need to be activated by StJAF13. Combined with expression analysis in potato tuber, results suggest that StbHLH1 and StJAF13 are key co-regulators of anthocyanin biosynthesis, while the transcripts of MYB variants StAN1, StMYBA1, and StMYB113 are well expressed, even in the absence of pigmentation. PMID:26884602

  19. Genes and gene regulation

    SciTech Connect

    MacLean, N.

    1988-01-01

    Genetics has long been a central topic for biologists, and recent progress has captured the public imagination as well. This book addresses questions that are at the leading edge of this continually advancing discipline. In tune with the increasing emphasis on molecular biology and genetic engineering, this text emphasizes the molecular aspects of gene expression, and the evolution of gene sequence organization and control. It reviews the genetic material of viruses, bacteria, and of higher organisms. Cells and organisms are compared in terms of gene numbers, their arrangements within a cell, and the control mechanisms which regulate the activity of genes.

  20. A putative functional MYB transcription factor induced by low temperature regulates anthocyanin biosynthesis in purple kale (Brassica Oleracea var. acephala f. tricolor).

    PubMed

    Zhang, Bin; Hu, Zongli; Zhang, Yanjie; Li, Yali; Zhou, Shuang; Chen, Guoping

    2012-02-01

    The purple kale (Brassica Oleracea var. acephala f. tricolor) is a mutation in kales, giving the mutant phenotype of brilliant purple color in the interior. Total anthocyanin analysis showed that the amount of anthocyanins in the purple kale was up to 1.73 mg g(-1) while no anthocyanin was detected in the white kale. To elucidate the molecular mechanism of the anthocyanin biosynthesis in the purple kale, we analyzed the expression of structural genes and some transcription factors associated with anthocyanin biosynthesis in the purple cultivar "Red Dove" and the white cultivar "White Dove". The result showed that nearly all the anthocyanin biosynthetic genes showed higher expression levels in the purple cultivar than in the white cultivar, especially for DFR and ANS, they were barely detected in the white cultivar. Interestingly, the fact that a R2R3 MYB transcription factor named BoPAP1 was extremely up-regulated in the purple kale and induced by low temperature attracted our attention. Further sequence analysis showed that BoPAP1 shared high similarity with AtPAP1 and BoMYB1. In addition, the anthocyanin accumulation in the purple kale is strongly induced by the low temperature stress. The total anthocyanin contents in the purple kale under low temperature were about 50-fold higher than the plants grown in the greenhouse. The expression of anthocyanin biosynthetic genes C4H, F3H, DFR, ANS and UFGT were all enhanced under the low temperature. These evidences strongly suggest that BoPAP1 may play an important role in activating the anthocyanin structural genes for the abundant anthocyanin accumulation in the purple kale.

  1. Activator- and repressor-type MYB transcription factors are involved in chilling injury induced flesh lignification in loquat via their interactions with the phenylpropanoid pathway

    PubMed Central

    Xu, Qian; Yin, Xue-ren; Zeng, Jiao-ke; Ge, Hang; Song, Min; Xu, Chang-jie; Li, Xian; Ferguson, Ian B.; Chen, Kun-song

    2014-01-01

    Lignin biosynthesis and its transcriptional regulatory networks have been studied in model plants and woody trees. However, lignification also occurs in some fleshy fruit and has rarely been considered in this way. Loquat (Eriobotrya japonica) is one such convenient tissue for exploring the transcription factors involved in regulating fruit flesh lignification. Firmness and lignin content of ‘Luoyangqing’ loquat were fund to increase during low-temperature storage as a typical symptom of chilling injury, while heat treatment (HT) and low-temperature conditioning (LTC) effectively alleviated them. Two novel EjMYB genes, EjMYB1 and EjMYB2, were isolated and were found to be localized in the nucleus. These genes responded differently to low temperature, with EjMYB1 induced and EjMYB2 inhibited at 0 °C. They also showed different temperature responses under HT and LTC conditions, and may be responsible for different regulation of flesh lignification at the transcriptional level. Transactivation assays indicated that EjMYB1 and EjMYB2 are a transcriptional activator and repressor, respectively. EjMYB1 activated promoters of both Arabidopsis and loquat lignin biosynthesis genes, while EjMYB2 countered the inductive effects of EjMYB1. This finding was also supported by transient overexpression in tobacco. Regulation of lignification by EjMYB1 and EjMYB2 is likely to be achieved via their competitive interaction with AC elements in the promoter region of lignin biosynthesis genes such as Ej4CL1. PMID:24860186

  2. Activator- and repressor-type MYB transcription factors are involved in chilling injury induced flesh lignification in loquat via their interactions with the phenylpropanoid pathway.

    PubMed

    Xu, Qian; Yin, Xue-ren; Zeng, Jiao-ke; Ge, Hang; Song, Min; Xu, Chang-Jie; Li, Xian; Ferguson, Ian B; Chen, Kun-song

    2014-08-01

    Lignin biosynthesis and its transcriptional regulatory networks have been studied in model plants and woody trees. However, lignification also occurs in some fleshy fruit and has rarely been considered in this way. Loquat ( Eriobotrya japonica ) is one such convenient tissue for exploring the transcription factors involved in regulating fruit flesh lignification. Firmness and lignin content of 'Luoyangqing' loquat were fund to increase during low-temperature storage as a typical symptom of chilling injury, while heat treatment (HT) and low-temperature conditioning (LTC) effectively alleviated them. Two novel EjMYB genes, EjMYB1 and EjMYB2, were isolated and were found to be localized in the nucleus. These genes responded differently to low temperature, with EjMYB1 induced and EjMYB2 inhibited at 0 °C. They also showed different temperature responses under HT and LTC conditions, and may be responsible for different regulation of flesh lignification at the transcriptional level. Transactivation assays indicated that EjMYB1 and EjMYB2 are a transcriptional activator and repressor, respectively. EjMYB1 activated promoters of both Arabidopsis and loquat lignin biosynthesis genes, while EjMYB2 countered the inductive effects of EjMYB1. This finding was also supported by transient overexpression in tobacco. Regulation of lignification by EjMYB1 and EjMYB2 is likely to be achieved via their competitive interaction with AC elements in the promoter region of lignin biosynthesis genes such as Ej4CL1.

  3. Identification and possible role of a MYB transcription factor from saffron (Crocus sativus).

    PubMed

    Gómez-Gómez, Lourdes; Trapero-Mozos, Almudena; Gómez, Maria Dolores; Rubio-Moraga, Angela; Ahrazem, Oussama

    2012-03-15

    The MYB family is the most abundant group of transcription factors described for plants. Plant MYB genes have been shown to be involved in the regulation of many aspects of plant development. No MYB genes are described for saffron, the dried stigma of Crocus sativus, utilized as a colorant for foodstuffs. In this study, we used RACE-PCR to isolate a full length cDNA of 894bp with a 591bp open reading frame, encoding a putative CsMYB1 from C. sativus. Comparison between gDNA and cDNA revealed no introns. Homology studies indicated that the deduced amino acid sequence is similar to members of the R2R3 MYB subfamily. Expression analysis showed the presence of high transcript levels in stigma tissue and low levels in tepals, whereas no signal was detected in either anthers or leaves. The RT-PCR analysis revealed that CsMYB1 expression is developmentally regulated during stigma development. Furthermore, expression analysis in stigmas from different Crocus species showed a correlation with stigma morphology. No transcripts were found in stigma tissues of Crocus species characterized by branched stigma morphology. Taken together, these results suggest that CsMYB1 may be involved in the regulation of stigma morphology in Crocus.

  4. Heterologous expression of IbMYB1a by different promoters exhibits different patterns of anthocyanin accumulation in tobacco.

    PubMed

    An, Chul Han; Lee, Ki-Won; Lee, Sang-Hoon; Jeong, Yu Jeong; Woo, Su Gyoung; Chun, Hyokon; Park, Youn-Il; Kwak, Sang-Soo; Kim, Cha Young

    2015-04-01

    We previously reported that the transient and stable expression of IbMYB1a produced anthocyanin pigmentation in tobacco leaves and transgenic Arabidopsis plants, respectively. To further determine the effects of different promoters on the expression of IbMYB1a and anthocyanin production, we generated and characterized stably transformed tobacco (Nicotiana tabacum SR1) plants expressing IbMYB1a under the control of three different promoters. We compared the differences in anthocyanin accumulation patterns and phenotypic features of the leaves of these transgenic tobacco plants during growth. Expression of IbMYB1a under the control of these three different promoters led to a remarkable variation in anthocyanin pigmentation in tobacco leaves. The anthocyanin contents of the leaves of the SPO-IbMYB1a-OX (SPO-M) line were higher than those of the SWPA2-IbMYB1a-OX (SPA-M) and 35S-IbMYB1a-OX (35S-M) lines. High levels of anthocyanin pigments negatively affected plant growth in the SPO-M lines, resulting delayed growth and, occasionally, a stunted phenotype. Furthermore, HPLC analysis revealed that transcriptional regulation of IbMYB1a led to the production of cyanidin-based anthocyanins in the tobacco plants. In addition, RT-PCR analysis revealed that IbMYB1a expression induced the up-regulation of several structural genes in the anthocyanin biosynthetic pathway, including DFR and ANS. Differential expression levels of IbMYB1a under the control of different promoters were highly correlated with the expression levels of the structural genes, thereby affecting anthocyanin production levels. These results indicate that IbMYB1a positively controls the expression of multiple anthocyanin biosynthetic genes and anthocyanin accumulation in heterologous tobacco plants. PMID:25681576

  5. CACTA-superfamily transposable element is inserted in MYB transcription factor gene of soybean line producing variegated seeds.

    PubMed

    Yan, Fan; Di, Shaokang; Takahashi, Ryoji

    2015-08-01

    The R gene of soybean, presumably encoding a MYB transcription factor, controls seed coat color. The gene consists of multiple alleles, R (black), r-m (black spots and (or) concentric streaks on brown seed), and r (brown seed). This study was conducted to determine the structure of the MYB transcription factor gene in a near-isogenic line (NIL) having r-m allele. PCR amplification of a fragment of the candidate gene Glyma.09G235100 generated a fragment of about 1 kb in the soybean cultivar Clark, whereas a fragment of about 14 kb in addition to fragments of 1 and 1.4 kb were produced in L72-2040, a Clark 63 NIL with the r-m allele. Clark 63 is a NIL of Clark with the rxp and Rps1 alleles. A DNA fragment of 13 060 bp was inserted in the intron of Glyma.09G235100 in L72-2040. The fragment had the CACTA motif at both ends, imperfect terminal inverted repeats (TIR), inverse repetition of short sequence motifs close to the 5' and 3' ends, and a duplication of three nucleotides at the site of integration, indicating that it belongs to a CACTA-superfamily transposable element. We designated the element as Tgm11. Overall nucleotide sequence, motifs of TIR, and subterminal repeats were similar to those of Tgm1 and Tgs1, suggesting that these elements comprise a family.

  6. Genome-Wide Identification and Characterization of R2R3MYB Family in Cucumis sativus

    PubMed Central

    Li, Qiang; Zhang, Cunjia; Li, Jing; Wang, Lina; Ren, Zhonghai

    2012-01-01

    Background The R2R3MYB proteins comprise one of the largest families of transcription factors in plants. Although genome-wide analysis of this family has been carried out in some species, little is known about R2R3MYB genes in cucumber (Cucumis sativus L.). Principal Findings This study has identified 55 R2R3MYB genes in the latest cucumber genome and the CsR2R3MYB family contained the smallest number of identified genes compared to other species that have been studied due to the absence of recent gene duplication events. These results were also supported by genome distribution and gene duplication analysis. Phylogenetic analysis showed that they could be classified into 11 subgroups. The evolutionary relationships and the intron - exon organizations that showed similarities with Arabidopsis, Vitis and Glycine R2R3MYB proteins were also analyzed and suggested strong gene conservation but also the expansions of particular functional genes during the evolution of the plant species. In addition, we found that 8 out of 55 (∼14.54%) cucumber R2R3MYB genes underwent alternative splicing events, producing a variety of transcripts from a single gene, which illustrated the extremely high complexity of transcriptome regulation. Tissue-specific expression profiles showed that 50 cucumber R2R3MYB genes were expressed in at least one of the tissues and the other 5 genes showed very low expression in all tissues tested, which suggested that cucumber R2R3MYB genes took part in many cellular processes. The transcript abundance level analysis during abiotic conditions (NaCl, ABA and low temperature treatments) identified a group of R2R3MYB genes that responded to one or more treatments. Conclusions This study has produced a comparative genomics analysis of the cucumber R2R3MYB gene family and has provided the first steps towards the selection of CsR2R3MYB genes for cloning and functional dissection that can be used in further studies to uncover their roles in cucumber growth and

  7. Expansion and diversification of the Populus R2R3-MYB family of transcription factors.

    PubMed

    Wilkins, Olivia; Nahal, Hardeep; Foong, Justin; Provart, Nicholas J; Campbell, Malcolm M

    2009-02-01

    The R2R3-MYB proteins comprise one of the largest families of transcription factors in plants. R2R3-MYB family members regulate plant-specific processes, such as the elaboration of specialized cell types, including xylem, guard cells, trichomes, and root hairs, and the biosynthesis of specialized branches of metabolism, including phenylpropanoid biosynthesis. As such, R2R3-MYB family members are hypothesized to contribute to the emergence of evolutionary innovations that have arisen in specific plant lineages. As a first step in determining the role played by R2R3-MYB family members in the emergence of lineage-specific innovations in the genus Populus, the entire Populus trichocarpa R2R3-MYB family was characterized. The Populus R2R3-MYB complement is much larger than that found in other angiosperms with fully sequenced genomes. Phylogenetic analyses, together with chromosome placement, showed that the expansion of the Populus R2R3-MYB family was not only attributable to whole genome duplication but also involved selective expansion of specific R2R3-MYB clades. Expansion of the Populus R2R3-MYB family prominently involved members with expression patterns that suggested a role in specific components of Populus life history, including wood formation and reproductive development. An expandable compendium of microarray-based expression data (PopGenExpress) and associated Web-based tools were developed to better enable within- and between-species comparisons of Populus R2R3-MYB gene expression. This resource, which includes intuitive graphic visualization of gene expression data across multiple tissues, organs, and treatments, is freely available to, and expandable by, scientists wishing to better understand the genome biology of Populus, an ecologically dominant and economically important forest tree genus. PMID:19091872

  8. Expansion and diversification of the Populus R2R3-MYB family of transcription factors.

    PubMed

    Wilkins, Olivia; Nahal, Hardeep; Foong, Justin; Provart, Nicholas J; Campbell, Malcolm M

    2009-02-01

    The R2R3-MYB proteins comprise one of the largest families of transcription factors in plants. R2R3-MYB family members regulate plant-specific processes, such as the elaboration of specialized cell types, including xylem, guard cells, trichomes, and root hairs, and the biosynthesis of specialized branches of metabolism, including phenylpropanoid biosynthesis. As such, R2R3-MYB family members are hypothesized to contribute to the emergence of evolutionary innovations that have arisen in specific plant lineages. As a first step in determining the role played by R2R3-MYB family members in the emergence of lineage-specific innovations in the genus Populus, the entire Populus trichocarpa R2R3-MYB family was characterized. The Populus R2R3-MYB complement is much larger than that found in other angiosperms with fully sequenced genomes. Phylogenetic analyses, together with chromosome placement, showed that the expansion of the Populus R2R3-MYB family was not only attributable to whole genome duplication but also involved selective expansion of specific R2R3-MYB clades. Expansion of the Populus R2R3-MYB family prominently involved members with expression patterns that suggested a role in specific components of Populus life history, including wood formation and reproductive development. An expandable compendium of microarray-based expression data (PopGenExpress) and associated Web-based tools were developed to better enable within- and between-species comparisons of Populus R2R3-MYB gene expression. This resource, which includes intuitive graphic visualization of gene expression data across multiple tissues, organs, and treatments, is freely available to, and expandable by, scientists wishing to better understand the genome biology of Populus, an ecologically dominant and economically important forest tree genus.

  9. A MYB transcription factor from the grey mangrove is induced by stress and confers NaCl tolerance in tobacco.

    PubMed

    Ganesan, G; Sankararamasubramanian, H M; Harikrishnan, M; Ganpudi, Ashwin; Ashwin, G; Parida, Ajay

    2012-07-01

    MYB transcription factor genes play important roles in developmental and various other processes in plants. In this study, functional characterization of AmMYB1, a single-repeat MYB transcription factor isolated from the salt-tolerant mangrove tree Avicennia marina is reported. AmMYB1 cDNA was 1046 bp in length with an open reading frame of 783 bp, encoding 260 amino acids. The corresponding gene had two introns and three exons and was present as a single copy in A. marina. The deduced amino acid sequence showed similarities to MYB proteins reported in other plants, including the conserved MYB binding domain. RNA gel blot analysis showed that the AmMYB1 transcript expression was more pronounced in green photosynthetic tissue and was strongly induced by stresses such as salt (500 mM), light (500 µE m(-2) s(-1)), and the exogenous application of ABA (100 µM). An analysis of the upstream sequence of AmMYB1 gene revealed the presence of regulatory elements identical to those present in the promoters of stress inducible genes. The promoter was responsive to NaCl and could enhance reporter gene expression in planta. An in vitro DNA binding assay using the promoter region (TGGTTAG) of the AtRD22 gene and a transactivation assay in yeast cells suggest the possibility of AmMYB1 protein regulating the expression of other genes during salt stress. Transgenic tobacco plants constitutively expressing the AmMYB1 transcription factor showed better tolerance to NaCl stress.

  10. Tight interconnection and multi-level control of Arabidopsis MYB44 in MAPK cascade signalling.

    PubMed

    Persak, Helene; Pitzschke, Andrea

    2013-01-01

    Abiotic stress poses a huge, ever-increasing problem to plants and agriculture. The dissection of signalling pathways mediating stress tolerance is a prerequisite to develop more resistant plant species. Mitogen-activated protein kinase (MAPK) cascades are universal signalling modules. In Arabidopsis, the MAPK MPK3 and its upstream regulator MAPK kinase MKK4 initiate the adaptation response to numerous abiotic and biotic stresses. Yet, molecular steps directly linked with MKK4-MPK3 activation are largely unknown. Starting with a yeast-two-hybrid screen for interacting partners of MKK4, we identified a transcription factor, MYB44. MYB44 is controlled at multiple levels by and strongly inter-connected with MAPK signalling. As we had shown earlier, stress-induced expression of the MYB44 gene is regulated by a MPK3-targeted bZIP transcription factor VIP1. At the protein level, MYB44 interacts with MPK3 in vivo. MYB44 is phosphorylated by MPK3 in vitro at a single residue, Ser145. Although replacement of Ser145 by a non-phosphorylatable (S145A) or phosphomimetic (S145D) residue did not alter MYB44 subcellular localisation, dimerization behaviour nor DNA-binding characteristics, abiotic stress tolerance tests in stable transgenic Arabidopsis plants clearly related S145 phosphorylation to MYB44 function: Compared to Arabidopsis wild type plants, MYB44 overexpressing lines exhibit an enhanced tolerance to osmotic stress and are slightly more sensitive to abscisic acid. Interestingly, overexpression of the S145A variant revealed that impaired phosphorylation does not render the MYB44 protein non-functional. Instead, S145A lines are highly sensitive to abiotic stress, and thereby remarkably similar to mpk3-deficient plants. Its in vivo interaction with the nuclear sub-pools of both MPK3 and MKK4 renders MYB44 the first plant transcription factor to have a second function as putative MAPK cascade scaffolding protein.

  11. Overexpression of MYB drives proliferation of CYLD‐defective cylindroma cells†

    PubMed Central

    Andersson, Mattias K; Sinclair, Naomi; Fehr, André; Hodgson, Kirsty; Lord, Christopher J; Kazakov, Dmitry V; Vanecek, Tomas; Ashworth, Alan; Stenman, Göran

    2016-01-01

    Abstract Cutaneous cylindroma is an adnexal tumour with apocrine differentiation. A predisposition to multiple cylindromas is seen in patients with Brooke–Spiegler syndrome, who carry germline mutations in the tumour suppressor gene CYLD. Previous studies of inherited cylindromas have highlighted the frequent presence of bi‐allelic truncating CYLD mutations as a recurrent driver mutation. We have previously shown that sporadic cylindromas express either MYB–NFIB fusion transcripts or show evidence of MYB activation in the absence of such fusions. Here, we investigated inherited cylindromas from several families with germline CYLD mutations for the presence of MYB activation. Strikingly, none of the inherited CYLD‐defective (n = 23) tumours expressed MYB–NFIB fusion transcripts. However, MYB expression was increased in the majority of tumours (69%) and global gene expression analysis revealed that well‐established MYB target genes were up‐regulated in CYLD‐defective tumours. Moreover, knock‐down of MYB expression caused a significant reduction in cylindroma cell proliferation, suggesting that MYB is also a key player and oncogenic driver in inherited cylindromas. Taken together, our findings suggest molecular heterogeneity in the pathogenesis of sporadic and inherited cutaneous cylindromas, with convergence on MYB activation. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. PMID:26969893

  12. Diversification of R2R3-MYB Transcription Factors in the Tomato Family Solanaceae.

    PubMed

    Gates, Daniel J; Strickler, Susan R; Mueller, Lukas A; Olson, Bradley J S C; Smith, Stacey D

    2016-08-01

    MYB transcription factors play an important role in regulating key plant developmental processes involving defense, cell shape, pigmentation, and root formation. Within this gene family, sequences containing an R2R3 MYB domain are the most abundant type and exhibit a wide diversity of functions. In this study, we identify 559 R2R3 MYB genes using whole genome data from four species of Solanaceae and reconstruct their evolutionary relationships. We compare the Solanaceae R2R3 MYBs to the well-characterized Arabidopsis thaliana sequences to estimate functional diversity and to identify gains and losses of MYB clades in the Solanaceae. We identify numerous R2R3 MYBs that do not appear closely related to Arabidopsis MYBs, and thus may represent clades of genes that have been lost along the Arabidopsis lineage or gained after the divergence of Rosid and Asterid lineages. Despite differences in the distribution of R2R3 MYBs across functional subgroups and species, the overall size of the R2R3 subfamily has changed relatively little over the roughly 50 million-year history of Solanaceae. We added our information regarding R2R3 MYBs in Solanaceae to other data and performed a meta-analysis to trace the evolution of subfamily size across land plants. The results reveal many shifts in the number of R2R3 genes, including a 54 % increase along the angiosperm stem lineage. The variation in R2R3 subfamily size across land plants is weakly positively correlated with genome size and strongly positively correlated with total number of genes. The retention of such a large number of R2R3 copies over long evolutionary time periods suggests that they have acquired new functions and been maintained by selection. Discovering the nature of this functional diversity will require integrating forward and reverse genetic approaches on an -omics scale.

  13. Possible Involvement of MYB44-Mediated Stomatal Regulation in Systemic Resistance Induced by Penicillium simplicissimum GP17-2 in Arabidopsis.

    PubMed

    Hieno, Ayaka; Naznin, Hushna Ara; Hyakumachi, Mitsuro; Higuchi-Takeuchi, Mieko; Matsui, Minami; Yamamoto, Yoshiharu Y

    2016-06-25

    The plant growth-promoting fungus (PGPF), Penicillium simplicissimum GP17-2 (GP17-2), induces systemic resistance against Pseudomonas syringae pv. tomato DC3000 (Pst) in Arabidopsis thaliana. The molecular mechanisms underlying induced systemic resistance (ISR) by GP17-2 were investigated in the present study. Microscopic observations revealed that stomatal reopening by Pst was restricted by elicitation with the culture filtrate (CF) from GP17-2. A gene expression analysis of MYB44, which enhances abscisic acid signaling and consequently closes stomata, revealed that the gene was activated by CF. CF-elicited myb44 mutant plants failed to restrict stomatal reopening and showed lower resistance to Pst than wild-type plants. These results indicate that stomatal resistance by GP17-2 is mediated by the gene activation of MYB44. We herein revealed that the MYB44-mediated prevention of penetration through the stomata is one of the components responsible for GP17-2-elicited ISR. PMID:27301421

  14. Possible Involvement of MYB44-Mediated Stomatal Regulation in Systemic Resistance Induced by Penicillium simplicissimum GP17-2 in Arabidopsis

    PubMed Central

    Hieno, Ayaka; Naznin, Hushna Ara; Hyakumachi, Mitsuro; Higuchi-Takeuchi, Mieko; Matsui, Minami; Yamamoto, Yoshiharu Y.

    2016-01-01

    The plant growth-promoting fungus (PGPF), Penicillium simplicissimum GP17-2 (GP17-2), induces systemic resistance against Pseudomonas syringae pv. tomato DC3000 (Pst) in Arabidopsis thaliana. The molecular mechanisms underlying induced systemic resistance (ISR) by GP17-2 were investigated in the present study. Microscopic observations revealed that stomatal reopening by Pst was restricted by elicitation with the culture filtrate (CF) from GP17-2. A gene expression analysis of MYB44, which enhances abscisic acid signaling and consequently closes stomata, revealed that the gene was activated by CF. CF-elicited myb44 mutant plants failed to restrict stomatal reopening and showed lower resistance to Pst than wild-type plants. These results indicate that stomatal resistance by GP17-2 is mediated by the gene activation of MYB44. We herein revealed that the MYB44-mediated prevention of penetration through the stomata is one of the components responsible for GP17-2-elicited ISR. PMID:27301421

  15. Functional analysis of three BrMYB28 transcription factors controlling the biosynthesis of glucosinolates in Brassica rapa.

    PubMed

    Seo, Mi-Suk; Jin, Mina; Chun, Jin-Hyuk; Kim, Sun-Ju; Park, Beom-Seok; Shon, Seong-Han; Kim, Jung Sun

    2016-03-01

    Glucosinolates (GSLs) are secondary metabolites that have anticarcinogenic activity and play defense roles in plants of the Brassicaceae family. MYB28 is known as a transcription factor that regulates aliphatic GSL biosynthesis in Arabidopsis thaliana. Brassicaceae plants have three orthologous copies of AtMYB28 derived from recent genome triplication. These BrMYB28 genes have a high level of sequence homology, with 81-87% similarities in the coding DNA sequence compared to Arabidopsis. Overexpression of three paralogous BrMYB28 genes in transgenic Chinese cabbage increased the total GSL content in all T1 generation plants and in two inbred lines of homozygous T2 plants. The highest total GSL contents were detected in homozygous T2 lines overexpressing BrMYB28.1, which showed an approximate fivefold increase compared to that of nontransgenic plants. The homozygous T2 lines with overexpressed BrMYB28.1 also showed an increased content of aliphatic, indolic, and aromatic GSLs compared to that of nontransgenic plants. Furthermore, all of the three BrMYB28 genes were identified as negative regulators of BrAOP2 and positive regulators of BrGSL-OH in the homozygous T2 lines. These data indicate the regulatory mechanism of GSL biosynthesis in B. rapa is unlike that in A. thaliana. Our results will provide useful information for elucidating the regulatory mechanism of GSL biosynthesis in polyploid plants.

  16. Functional analysis of three BrMYB28 transcription factors controlling the biosynthesis of glucosinolates in Brassica rapa.

    PubMed

    Seo, Mi-Suk; Jin, Mina; Chun, Jin-Hyuk; Kim, Sun-Ju; Park, Beom-Seok; Shon, Seong-Han; Kim, Jung Sun

    2016-03-01

    Glucosinolates (GSLs) are secondary metabolites that have anticarcinogenic activity and play defense roles in plants of the Brassicaceae family. MYB28 is known as a transcription factor that regulates aliphatic GSL biosynthesis in Arabidopsis thaliana. Brassicaceae plants have three orthologous copies of AtMYB28 derived from recent genome triplication. These BrMYB28 genes have a high level of sequence homology, with 81-87% similarities in the coding DNA sequence compared to Arabidopsis. Overexpression of three paralogous BrMYB28 genes in transgenic Chinese cabbage increased the total GSL content in all T1 generation plants and in two inbred lines of homozygous T2 plants. The highest total GSL contents were detected in homozygous T2 lines overexpressing BrMYB28.1, which showed an approximate fivefold increase compared to that of nontransgenic plants. The homozygous T2 lines with overexpressed BrMYB28.1 also showed an increased content of aliphatic, indolic, and aromatic GSLs compared to that of nontransgenic plants. Furthermore, all of the three BrMYB28 genes were identified as negative regulators of BrAOP2 and positive regulators of BrGSL-OH in the homozygous T2 lines. These data indicate the regulatory mechanism of GSL biosynthesis in B. rapa is unlike that in A. thaliana. Our results will provide useful information for elucidating the regulatory mechanism of GSL biosynthesis in polyploid plants. PMID:26820138

  17. Phosphatidic acid interacts with a MYB transcription factor and regulates its nuclear localization and function in Arabidopsis.

    PubMed

    Yao, Hongyan; Wang, Geliang; Guo, Liang; Wang, Xuemin

    2013-12-01

    Phosphatidic acid (PA) has emerged as a class of cellular mediators involved in various cellular and physiological processes, but little is known about its mechanism of action. Here we show that PA interacts with werewolf (WER), a R2R3 MYB transcription factor involved in root hair formation. The PA-interacting region is confined to the end of the R2 subdomain. The ablation of the PA binding motif has no effect on WER binding to DNA, but abolishes its nuclear localization and its function in regulating epidermal cell fate. Inhibition of PA production by phospholipase Dζ also suppresses WER's nuclear localization, root hair formation, and elongation. These results suggest a role for PA in promoting protein nuclear localization.

  18. Phosphatidic Acid Interacts with a MYB Transcription Factor and Regulates Its Nuclear Localization and Function in Arabidopsis[C][W

    PubMed Central

    Yao, Hongyan; Wang, Geliang; Guo, Liang; Wang, Xuemin

    2013-01-01

    Phosphatidic acid (PA) has emerged as a class of cellular mediators involved in various cellular and physiological processes, but little is known about its mechanism of action. Here we show that PA interacts with WEREWOLF (WER), a R2R3 MYB transcription factor involved in root hair formation. The PA-interacting region is confined to the end of the R2 subdomain. The ablation of the PA binding motif has no effect on WER binding to DNA, but abolishes its nuclear localization and its function in regulating epidermal cell fate. Inhibition of PA production by phospholipase Dζ also suppresses WER’s nuclear localization, root hair formation, and elongation. These results suggest a role for PA in promoting protein nuclear localization. PMID:24368785

  19. Red colouration in apple fruit is due to the activity of the MYB transcription factor, MdMYB10.

    PubMed

    Espley, Richard V; Hellens, Roger P; Putterill, Jo; Stevenson, David E; Kutty-Amma, Sumathi; Allan, Andrew C

    2007-02-01

    Anthocyanin concentration is an important determinant of the colour of many fruits. In apple (Malus x domestica), centuries of breeding have produced numerous varieties in which levels of anthocyanin pigment vary widely and change in response to environmental and developmental stimuli. The apple fruit cortex is usually colourless, although germplasm does exist where the cortex is highly pigmented due to the accumulation of either anthocyanins or carotenoids. From studies in a diverse array of plant species, it is apparent that anthocyanin biosynthesis is controlled at the level of transcription. Here we report the transcript levels of the anthocyanin biosynthetic genes in a red-fleshed apple compared with a white-fleshed cultivar. We also describe an apple MYB transcription factor, MdMYB10, that is similar in sequence to known anthocyanin regulators in other species. We further show that this transcription factor can induce anthocyanin accumulation in both heterologous and homologous systems, generating pigmented patches in transient assays in tobacco leaves and highly pigmented apple plants following stable transformation with constitutively expressed MdMYB10. Efficient induction of anthocyanin biosynthesis in transient assays by MdMYB10 was dependent on the co-expression of two distinct bHLH proteins from apple, MdbHLH3 and MdbHLH33. The strong correlation between the expression of MdMYB10 and apple anthocyanin levels during fruit development suggests that this transcription factor is responsible for controlling anthocyanin biosynthesis in apple fruit; in the red-fleshed cultivar and in the skin of other varieties, there is an induction of MdMYB10 expression concurrent with colour formation during development. Characterization of MdMYB10 has implications for the development of new varieties through classical breeding or a biotechnological approach.

  20. A Transcription Factor γMYB1 Binds to the P1BS cis-Element and Activates PLA2-γ Expression with its Co-Activator γMYB2.

    PubMed

    Nguyen, Ha Thi Kim; Kim, Soo Youn; Cho, Kwang-Moon; Hong, Jong Chan; Shin, Jeong Sheop; Kim, Hae Jin

    2016-04-01

    Phospholipase A2(PLA2) hydrolyzes phospholipid molecules to produce two products that are both precursors of second messengers of signaling pathways and signaling molecules per se.Arabidopsis thaliana PLA2 paralogs (-β,-γ and -δ) play critical roles during pollen development, pollen germination and tube growth. In this study, analysis of the PLA2-γ promoter using a deletion series revealed that the promoter region -153 to -1 is crucial for its pollen specificity. Using a yeast one-hybrid screening assay with the PLA2-γ promoter and an Arabidopsis transcription factor (TF)-only library, we isolated two novel MYB-like TFs belonging to the MYB-CC family, denoted here as γMYB1 and γMYB2. By electrophoretic mobility shift assay, we found that these two TFs bind directly to the P1BS (phosphate starvation response 1-binding sequence)cis-element of the PLA2-γ promoter. γMYB1 alone functioned as a transcriptional activator for PLA2-γ expression, whereas γMYB2 directly interacted with γMYB1 and enhanced its activation. Overexpression of γMYB1 in the mature pollen grain led to increased expression of not only the PLA2-γ gene but also of several genes whose promoters contain the P1BS cis-element and which are involved in the Pi starvation response, phospholipid biosynthesis and sugar synthesis. Based on these results, we suggest that the TF γMYB1 binds to the P1BS cis-element, activates the expression of PLA2-γ with the assistance of its co-activator, γMYB2, and regulates the expression of several target genes involved in many plant metabolic reactions. PMID:26872838

  1. Regulatory domains of the A-Myb transcription factor and its interaction with the CBP/p300 adaptor molecules.

    PubMed Central

    Facchinetti, V; Loffarelli, L; Schreek, S; Oelgeschläger, M; Lüscher, B; Introna, M; Golay, J

    1997-01-01

    The A-Myb transcription factor belongs to the Myb family of oncoproteins and is likely to be involved in the regulation of proliferation and/or differentiation of normal B cells and Burkitt's lymphoma cells. To characterize in detail the domains of A-Myb that regulate its function, we have generated a series of deletion mutants and have investigated their trans-activation potential as well as their DNA-binding activity. Our results have allowed us to delineate the trans-activation domain as well as two separate regulatory regions. The boundaries of the trans-activation domain (amino acid residues 218-319) are centred on a sequence rich in charged amino acids (residues 259-281). A region (residues 320-482) localized immediately downstream of the trans-activation domain and containing a newly identified conserved stretch of 48 residues markedly inhibits specific DNA binding. Finally the last 110 residues of A-Myb (residues 643-752), which include a sequence conserved in all mammalian myb genes (region III), negatively regulate the maximal trans-activation potential of A-Myb. We have also investigated the functional interaction between A-Myb and the nuclear adaptor molecule CBP [cAMP response element-binding protein (CREB)-binding protein]. We demonstrate that CBP synergizes with A-Myb in a dose-dependent fashion, and that this co-operative effect can be inhibited by E1A and can also be observed with the CBP homologue p300. We show that this functional synergism requires the presence of the A-Myb charged sequence and that it involves physical interaction between A-Myb and the CREB-binding domain of CBP. PMID:9210395

  2. Characterization of a citrus R2R3-MYB transcription factor that regulates the flavonol and hydroxycinnamic acid biosynthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavonols and hydroxycinnamic acids are important phenylpropanoid metabolites in plants. In this study, we isolated and characterized a citrus R2R3-MYB transcription factor CsMYBF1, encoding a protein belonging to the flavonol-specific MYB subgroup. Ectopic expression of CsMYBF1 in tomato led to an ...

  3. Function of MYB domain transcription factors in abiotic stress and epigenetic control of stress response in plant genome

    PubMed Central

    Roy, Sujit

    2016-01-01

    ABSTRACT Plants have developed highly efficient and remarkable mechanisms to survive under frequent and extreme environmental stress conditions. Exposure of plants to various stress factors is associated with coordinated changes in gene expression at the transcriptional level and hence transcription factors, such as those belonging to the MYB family play a central role in triggering the right responses. MYB transcription factors have been extensively studied in regard of their involvement in the regulation of a number of such stress responses in plants. Genetic and molecular biological studies, primarily in Arabidopsis, have also begun to unravel the role of MYB transcription factors in the epigenetic regulation of stress responses in plants. This review focuses on the role of MYB transcription factors in the regulation of various stress responses in general, highlighting on recent advances in our understanding of the involvement of this class of transcription factors in epigenetic regulation of stress response in plant genome. PMID:26636625

  4. Analysis of interactions between heterologously produced bHLH and MYB proteins that regulate anthocyanin biosynthesis: quantitative interaction kinetics by Microscale Thermophoresis.

    PubMed

    Nemie-Feyissa, Dugassa; Heidari, Behzad; Blaise, Mickael; Lillo, Cathrine

    2015-03-01

    The two Arabidopsis basic-helix-loop-helix transcription factors GLABRA3 (GL3) and ENHANCER OF GLABRA3 (EGL3) are positive regulators of anthocyanin biosynthesis, and form protein complexes (MBW complexes) with various R2R3 MYB transcription factors and a WD40 repeat protein TRANSPARENT TESTA GLABROUS1 (TTG1). In earlier studies, GL3, in contrast to EGL3, was shown to be essential for accumulation of anthocyanins in response to nitrogen depletion. This could not be fully explained by the strong induction of GL3 in response to nitrogen depletion because the EGL3 transcripts were constitutively at a relatively high level and transcripts levels of the two genes were similar under nitrogen depletion. Here the GL3 and EGL3 proteins were characterized with respect to their affinities for PRODUCTION OF ANTHOCYANIN PIGMENT2 (PAP2), a R2R3-MYB which is induced by nitrogen depletion and is part of MBW complexes promoting anthocyanin synthesis. GL3 and EGL3 were also tested for their binding to MYBL2, a negative regulator of anthocyanin synthesis and MBW complexes. Using heterologously expressed proteins and Microscale Thermophoresis, GL3 showed binding constants (Kd) of 3.5±1.7 and 22.7±3.7 μM, whereas EGL3 showed binding constants of 7.5±2.3 and 8.9±1.4 μM for PAP2 and MYBL2, respectively. This implies that MYBL2 will not inhibit a MBW complex containing GL3 as easily as for a complex containing EGL3. In transgenic plants where EGL3 reaches high concentrations compared with MYBL2 the equilibrium is shifted and MYBL2 is not likely to be an efficient competitor, hence anthocyanin formation could be restored by either EGL3 or GL3 genes when overexpressed by help of the 35S promoter. The present work underpins that GL3 is essential for anthocyanin accumulation under nitrogen depletion not only due to transcriptional activation, but also because of binding properties to proteins promoting or inhibiting the activity of the MBW complex. PMID:25659750

  5. QsMYB1 expression is modulated in response to heat and drought stresses and during plant recovery in Quercus suber.

    PubMed

    Almeida, Tânia; Pinto, Glória; Correia, Barbara; Santos, Conceição; Gonçalves, Sónia

    2013-12-01

    Cork oak is an economically important forest species showing a great tolerance to high temperatures and shortage of water. However, the mechanisms underlying this plasticity are still poorly understood. Among the stress regulators, transcription factors (TFs) are especially important since they can control a wide range of stress-inducible genes, which make them powerful targets for genetic engineering of stress tolerance. Here we evaluated the influence of increasing temperatures (up to 55 °C) or drought (18% field capacity, FC) on the expression profile of an R2R3-MYB transcription factor of cork oak, the QsMYB1. QsMYB1 was previously identified as being preferentially expressed in cork tissues and as having an associated alternative splicing mechanism, which results in two different transcripts (QsMYB1.1 and QsMYB1.2). Expression analysis by reverse transcription quantitative PCR (RT-qPCR) revealed that increasing temperatures led to a gradual down-regulation of QsMYB1 transcripts with more effect on QsMYB1.1 abundance. On the other hand, under drought condition, expression of QsMYB1 variants, mainly the QsMYB1.2, was transiently up-regulated shortly after the stress imposition. Recovery from each stress has also resulted in a differential response by both QsMYB1 transcripts. Several physiological and biochemical parameters (plant water status, chlorophyll fluorescence, lipid peroxidation and proline content) were determined in order to monitor the plant performance under stress and recovery. In conclusion, this report provides the first evidence that QsMYB1 TF may have a putative function in the regulatory network of cork oak response to heat and drought stresses and during plant recovery.

  6. Molecular characterization of an MYB transcription factor from a succulent halophyte involved in stress tolerance

    PubMed Central

    Shukla, Pushp Sheel; Agarwal, Parinita; Gupta, Kapil; Agarwal, Pradeep K.

    2015-01-01

    Abiotic stresses like drought, salinity and extreme temperature significantly affect crop productivity. Plants respond at molecular, cellular and physiological levels for management of stress tolerance. Functional and regulatory genes play a major role in controlling these abiotic stresses through an intricate network of transcriptional machinery. Transcription factors are potential tools for manipulating stress tolerance since they control a large number of downstream genes. In the present study, we have isolated SbMYB44 from a succulent halophyte, Salicornia brachiata Roxb. SbMYB44 with an open-reading frame of 810 bp encodes a protein of 269 amino acids, with an estimated molecular mass of 30.31 kDa and an isoelectric point of 6.29. The in silico analysis revealed that the SbMYB44 protein contains the conserved R2R3 imperfect repeats, two SANT domains and post-translational modification sites. The SbMYB44 transcript showed up-regulation in response to salinity, desiccation, high temperature, and abscisic acid and salicylic acid treatments. The SbMYB44 recombinant protein showed binding to dehydration-responsive cis-elements (RD22 and MBS-1), suggesting its possible role in stress signalling. Overexpression of SbMYB44 enhanced the growth of yeast cells under both ionic and osmotic stresses. PMID:25986050

  7. A functional interaction of E7 with B-Myb-MuvB complex promotes acute cooperative transcriptional activation of both S- and M-phase genes. (129 c).

    PubMed

    Pang, C L; Toh, S Y; He, P; Teissier, S; Ben Khalifa, Y; Xue, Y; Thierry, F

    2014-07-31

    High-risk human papillomaviruses are causative agents of cervical cancer. Viral protein E7 is required to establish and maintain the pro-oncogenic phenotype in infected cells, but the molecular mechanisms by which E7 promotes carcinogenesis are only partially understood. Our transcriptome analyses in primary human fibroblasts transduced with the viral protein revealed that E7 activates a group of mitotic genes via the activator B-Myb-MuvB complex. We show that E7 interacts with the B-Myb, FoxM1 and LIN9 components of this activator complex, leading to cooperative transcriptional activation of mitotic genes in primary cells and E7 recruitment to the corresponding promoters. E7 interaction with LIN9 and FoxM1 depended on the LXCXE motif, which is also required for pocket protein interaction and degradation. Using E7 mutants for the degradation of pocket proteins but intact for the LXCXE motif, we demonstrate that E7 functional interaction with the B-Myb-MuvB complex and pocket protein degradation are two discrete functions of the viral protein that cooperate to promote acute transcriptional activation of mitotic genes. Transcriptional level of E7 in patient's cervical lesions at different stages of progression was shown to correlate with those of B-Myb and FoxM1 as well as other mitotic gene transcripts, thereby linking E7 with cellular proliferation and progression in cervical cancer in vivo. E7 thus can directly activate the transcriptional levels of cell cycle genes independently of pocket protein stability.

  8. bHLH05 Is an Interaction Partner of MYB51 and a Novel Regulator of Glucosinolate Biosynthesis in Arabidopsis1[W][OPEN

    PubMed Central

    Gigolashvili, Tamara

    2014-01-01

    By means of yeast (Saccharomyces cerevisiae) two-hybrid screening, we identified basic helix-loop-helix transcription factor05 (bHLH05) as an interacting partner of MYB51, the key regulator of indolic glucosinolates (GSLs) in Arabidopsis (Arabidopsis thaliana). Furthermore, we show that bHLH04, bHLH05, and bHLH06/MYC2 also interact with other R2R3-MYBs regulating GSL biosynthesis. Analysis of bhlh loss-of-function mutants revealed that the single bhlh mutants retained GSL levels that were similar to those in wild-type plants, whereas the triple bhlh04/05/06 mutant was depleted in the production of GSL. Unlike bhlh04/06 and bhlh05/06 mutants, the double bhlh04/05 mutant was strongly affected in the production of GSL, pointing to a special role of bHLH04 and bHLH05 in the control of GSL levels in the absence of jasmonic acid. The combination of two specific gain-of-function alleles of MYB and bHLH proteins had an additive effect on GSL levels, as demonstrated by the analysis of the double MYB34-1D bHLH05D94N mutant, which produces 20-fold more indolic GSLs than bHLH05D94N and ecotype Columbia-0 of Arabidopsis. The amino acid substitution D94N in bHLH05D94N negatively affects the interaction with JASMONATE-ZIM DOMAIN protein, thereby resulting in constitutive activation of bHLH05 and mimicking jasmonic acid treatment. Our study revealed the bHLH04, bHLH05, and bHLH06/MYC2 factors as novel regulators of GSL biosynthesis in Arabidopsis. PMID:25049362

  9. The Myb-p300-CREB axis modulates intestine homeostasis, radiosensitivity and tumorigenesis

    PubMed Central

    Sampurno, S; Bijenhof, A; Cheasley, D; Xu, H; Robine, S; Hilton, D; Alexander, W S; Pereira, L; Mantamadiotis, T; Malaterre, J; Ramsay, R G

    2013-01-01

    The gastrointestinal (GI) epithelium is constantly renewing, depending upon the intestinal stem cells (ISC) regulated by a spectrum of transcription factors (TFs), including Myb. We noted previously in mice with a p300 mutation (plt6) within the Myb-interaction-domain phenocopied Myb hypomorphic mutant mice with regard to thrombopoiesis, and here, changes in GI homeostasis. p300 is a transcriptional coactivator for many TFs, most prominently cyclic-AMP response element-binding protein (CREB), and also Myb. Studies have highlighted the importance of CREB in proliferation and radiosensitivity, but not in the GI. This prompted us to directly investigate the p300–Myb–CREB axis in the GI. Here, the role of CREB has been defined by generating GI-specific inducible creb knockout (KO) mice. KO mice show efficient and specific deletion of CREB, with no evident compensation by CREM and ATF1. Despite complete KO, only modest effects on proliferation, radiosensitivity and differentiation in the GI under homeostatic or stress conditions were evident, even though CREB target gene pcna (proliferating cell nuclear antigen) was downregulated. creb and p300 mutant lines show increased goblet cells, whereas a reduction in enteroendocrine cells was apparent only in the p300 line, further resembling the Myb hypomorphs. When propagated in vitro, crebKO ISC were defective in organoid formation, suggesting that the GI stroma compensates for CREB loss in vivo, unlike in MybKO studies. Thus, it appears that p300 regulates GI differentiation primarily through Myb, rather than CREB. Finally, active pCREB is elevated in colorectal cancer (CRC) cells and adenomas, and is required for the expression of drug transporter, MRP2, associated with resistance to Oxaliplatin as well as several chromatin cohesion protein that are relevant to CRC therapy. These data raise the prospect that CREB may have a role in GI malignancy as it does in other cancer types, but unlike Myb, is not critical for GI

  10. Sugarcane transgenics expressing MYB transcription factors show improved glucose release

    DOE PAGESBeta

    Poovaiah, Charleson R.; Bewg, William P.; Lan, Wu; Ralph, John; Coleman, Heather D.

    2016-07-15

    In this study, sugarcane, a tropical C4 perennial crop, is capable of producing 30-100 tons or more of biomass per hectare annually. The lignocellulosic residue remaining after sugar extraction is currently underutilized and can provide a significant source of biomass for the production of second-generation bioethanol. As a result, MYB31 and MYB42 were cloned from maize and expressed in sugarcane with and without the UTR sequences. The cloned sequences were 98 and 99 % identical to the published nucleotide sequences. The inclusion of the UTR sequences did not affect any of the parameters tested. There was little difference in plantmore » height and the number of internodes of the MYB-overexpressing sugarcane plants when compared with controls. MYB transgene expression determined by qPCR exhibited continued expression in young and maturing internodes. MYB31 downregulated more genes within the lignin biosynthetic pathway than MYB42. MYB31 and MYB42 expression resulted in decreased lignin content in some lines. All MYB42 plants further analyzed showed significant increases in glucose release by enzymatic hydrolysis in 72 h, whereas only two MYB31 plants released more glucose than control plants. This correlated directly with a significant decrease in acid-insoluble lignin. Soluble sucrose content of the MYB42 transgenic plants did not vary compared to control plants. In conclusion, this study demonstrates the use of MYB transcription factors to improve the production of bioethanol from sugarcane bagasse remaining after sugar extraction.« less

  11. Immunomodulation by MYB is associated with tumor relapse in patients with early stage colorectal cancer.

    PubMed

    Millen, Rosemary; Malaterre, Jordane; Cross, Ryan S; Carpinteri, Sandra; Desai, Jayesh; Tran, Ben; Darcy, Phillip; Gibbs, Peter; Sieber, Oliver; Zeps, Nikolajs; Waring, Paul; Fox, Stephen; Pereira, Lloyd; Ramsay, Robert G

    2016-07-01

    The presence of tumor immune infiltrating cells (TILs), particularly CD8(+) T-cells, is a robust predictor of outcome in patients with colorectal cancer (CRC). We revisited TIL abundance specifically in patients with microsatellite stable (MSS) CRC without evidence of lymph node or metastatic spread. Examination of the density of CD8(+) T-cells in primary tumors in the context of other pro-oncogenic markers was performed to investigate potential regulators of TILs. Two independent cohorts of patients with MSS T2-4N0M0 CRC, enriched for cases with atypical relapse, were investigated. We quantified CD8(+) and CD45RO(+) -TILs, inflammatory markers, NFkBp65, pStat3, Cyclo-oxygenase-2 (COX2) and GRP78 as well as transcription factors (TF), β-catenin and MYB. High CD8(+) TILs correlated with a better relapse-free survival in both cohorts (p = 0.002) with MYB and its target gene, GRP78 being higher in the relapse group (p = 0.001); no difference in pSTAT3 and p65 was observed. A mouse CRC (CT26) model was employed to evaluate the effect of MYB on GRP78 expression as well as T-cell infiltration. MYB over-expressing in CT26 cells increased GRP78 expression and the analysis of tumor-draining lymph nodes adjacent to tumors showed reduced T-cell activation. Furthermore, MYB over-expression reduced the efficacy of anti-PD-1 to modulate CT26 tumor growth. This high MYB and GRP78 show a reciprocal relationship with CD8(+) TILs which may be useful refining the prediction of patient outcome. These data reveal a new immunomodulatory function for MYB suggesting a basis for further development of anti-GRP78 and/or anti-MYB therapies. PMID:27622014

  12. Immunomodulation by MYB is associated with tumor relapse in patients with early stage colorectal cancer

    PubMed Central

    Millen, Rosemary; Malaterre, Jordane; Cross, Ryan S.; Carpinteri, Sandra; Desai, Jayesh; Tran, Ben; Darcy, Phillip; Gibbs, Peter; Sieber, Oliver; Zeps, Nikolajs; Waring, Paul; Fox, Stephen; Pereira, Lloyd; Ramsay, Robert G.

    2016-01-01

    ABSTRACT The presence of tumor immune infiltrating cells (TILs), particularly CD8+ T-cells, is a robust predictor of outcome in patients with colorectal cancer (CRC). We revisited TIL abundance specifically in patients with microsatellite stable (MSS) CRC without evidence of lymph node or metastatic spread. Examination of the density of CD8+ T-cells in primary tumors in the context of other pro-oncogenic markers was performed to investigate potential regulators of TILs. Two independent cohorts of patients with MSS T2-4N0M0 CRC, enriched for cases with atypical relapse, were investigated. We quantified CD8+ and CD45RO+ -TILs, inflammatory markers, NFkBp65, pStat3, Cyclo-oxygenase-2 (COX2) and GRP78 as well as transcription factors (TF), β-catenin and MYB. High CD8+ TILs correlated with a better relapse-free survival in both cohorts (p = 0.002) with MYB and its target gene, GRP78 being higher in the relapse group (p = 0.001); no difference in pSTAT3 and p65 was observed. A mouse CRC (CT26) model was employed to evaluate the effect of MYB on GRP78 expression as well as T-cell infiltration. MYB over-expressing in CT26 cells increased GRP78 expression and the analysis of tumor-draining lymph nodes adjacent to tumors showed reduced T-cell activation. Furthermore, MYB over-expression reduced the efficacy of anti-PD-1 to modulate CT26 tumor growth. This high MYB and GRP78 show a reciprocal relationship with CD8+ TILs which may be useful refining the prediction of patient outcome. These data reveal a new immunomodulatory function for MYB suggesting a basis for further development of anti-GRP78 and/or anti-MYB therapies. PMID:27622014

  13. Immunomodulation by MYB is associated with tumor relapse in patients with early stage colorectal cancer

    PubMed Central

    Millen, Rosemary; Malaterre, Jordane; Cross, Ryan S.; Carpinteri, Sandra; Desai, Jayesh; Tran, Ben; Darcy, Phillip; Gibbs, Peter; Sieber, Oliver; Zeps, Nikolajs; Waring, Paul; Fox, Stephen; Pereira, Lloyd; Ramsay, Robert G.

    2016-01-01

    ABSTRACT The presence of tumor immune infiltrating cells (TILs), particularly CD8+ T-cells, is a robust predictor of outcome in patients with colorectal cancer (CRC). We revisited TIL abundance specifically in patients with microsatellite stable (MSS) CRC without evidence of lymph node or metastatic spread. Examination of the density of CD8+ T-cells in primary tumors in the context of other pro-oncogenic markers was performed to investigate potential regulators of TILs. Two independent cohorts of patients with MSS T2-4N0M0 CRC, enriched for cases with atypical relapse, were investigated. We quantified CD8+ and CD45RO+ -TILs, inflammatory markers, NFkBp65, pStat3, Cyclo-oxygenase-2 (COX2) and GRP78 as well as transcription factors (TF), β-catenin and MYB. High CD8+ TILs correlated with a better relapse-free survival in both cohorts (p = 0.002) with MYB and its target gene, GRP78 being higher in the relapse group (p = 0.001); no difference in pSTAT3 and p65 was observed. A mouse CRC (CT26) model was employed to evaluate the effect of MYB on GRP78 expression as well as T-cell infiltration. MYB over-expressing in CT26 cells increased GRP78 expression and the analysis of tumor-draining lymph nodes adjacent to tumors showed reduced T-cell activation. Furthermore, MYB over-expression reduced the efficacy of anti-PD-1 to modulate CT26 tumor growth. This high MYB and GRP78 show a reciprocal relationship with CD8+ TILs which may be useful refining the prediction of patient outcome. These data reveal a new immunomodulatory function for MYB suggesting a basis for further development of anti-GRP78 and/or anti-MYB therapies.

  14. Rhizobacterial volatiles and photosynthesis-related signals coordinate MYB72 expression in Arabidopsis roots during onset of induced systemic resistance and iron-deficiency responses.

    PubMed

    Zamioudis, Christos; Korteland, Jolanda; Van Pelt, Johan A; van Hamersveld, Muriël; Dombrowski, Nina; Bai, Yang; Hanson, Johannes; Van Verk, Marcel C; Ling, Hong-Qing; Schulze-Lefert, Paul; Pieterse, Corné M J

    2015-10-01

    In Arabidopsis roots, the transcription factor MYB72 plays a dual role in the onset of rhizobacteria-induced systemic resistance (ISR) and plant survival under conditions of limited iron availability. Previously, it was shown that MYB72 coordinates the expression of a gene module that promotes synthesis and excretion of iron-mobilizing phenolic compounds in the rhizosphere, a process that is involved in both iron acquisition and ISR signaling. Here, we show that volatile organic compounds (VOCs) from ISR-inducing Pseudomonas bacteria are important elicitors of MYB72. In response to VOC treatment, MYB72 is co-expressed with the iron uptake-related genes FERRIC REDUCTION OXIDASE 2 (FRO2) and IRON-REGULATED TRANSPORTER 1 (IRT1) in a manner that is dependent on FER-LIKE IRON DEFICIENCY TRANSCRIPTION FACTOR (FIT), indicating that MYB72 is an intrinsic part of the plant's iron-acquisition response that is typically activated upon iron starvation. However, VOC-induced MYB72 expression is activated independently of iron availability in the root vicinity. Moreover, rhizobacterial VOC-mediated induction of MYB72 requires photosynthesis-related signals, while iron deficiency in the rhizosphere activates MYB72 in the absence of shoot-derived signals. Together, these results show that the ISR- and iron acquisition-related transcription factor MYB72 in Arabidopsis roots is activated by rhizobacterial volatiles and photosynthesis-related signals, and enhances the iron-acquisition capacity of roots independently of the iron availability in the rhizosphere. This work highlights the role of MYB72 in plant processes by which root microbiota simultaneously stimulate systemic immunity and activate the iron-uptake machinery in their host plants.

  15. MYB46 Modulates Disease Susceptibility to Botrytis cinerea in Arabidopsis12[W

    PubMed Central

    Ramírez, Vicente; Agorio, Astrid; Coego, Alberto; García-Andrade, Javier; Hernández, M. José; Balaguer, Begoña; Ouwerkerk, Pieter B.F.; Zarra, Ignacio; Vera, Pablo

    2011-01-01

    In this study, we show that the Arabidopsis (Arabidopsis thaliana) transcription factor MYB46, previously described to regulate secondary cell wall biosynthesis in the vascular tissue of the stem, is pivotal for mediating disease susceptibility to the fungal pathogen Botrytis cinerea. We identified MYB46 by its ability to bind to a new cis-element located in the 5′ promoter region of the pathogen-induced Ep5C gene, which encodes a type III cell wall-bound peroxidase. We present genetic and molecular evidence indicating that MYB46 modulates the magnitude of Ep5C gene induction following pathogenic insults. Moreover, we demonstrate that different myb46 knockdown mutant plants exhibit increased disease resistance to B. cinerea, a phenotype that is accompanied by selective transcriptional reprogramming of a set of genes encoding cell wall proteins and enzymes, of which extracellular type III peroxidases are conspicuous. In essence, our results substantiate that defense-related signaling pathways and cell wall integrity are interconnected and that MYB46 likely functions as a disease susceptibility modulator to B. cinerea through the integration of cell wall remodeling and downstream activation of secondary lines of defense. PMID:21282403

  16. New member of the R2R3-MYB transcription factors family in grapevine suppresses the anthocyanin accumulation in the flowers of transgenic tobacco.

    PubMed

    Pérez-Díaz, J Ricardo; Pérez-Díaz, Jorge; Madrid-Espinoza, José; González-Villanueva, Enrique; Moreno, Yerko; Ruiz-Lara, Simón

    2016-01-01

    In grapevine, anthocyanins and proanthocyanidins are the main flavonoids in berries, which are associated to organoleptic properties in red wine such as color and astringency. Flavonoid pathway is specifically regulated at transcriptional level and several R2R3-MYB proteins have shown to act as positive regulators. However, some members of this family have shown to repress the flavonoid biosynthesis. In this work, we present the characterization of VvMYB4-like gene, which encodes a putative transcriptional factor highly expressed in the skin of berries at the pre veraison stage in grapevine. Its over-expression in tobacco resulted in the loss of pigmentation in flowers due a decrease in anthocyanin accumulation. Severity in anthocyanin suppression observed in petals could be associated with the expression level of the VvMYB4-like transgene. Expression analysis of flavonoid structural genes revealed the strong down-regulation of the flavonoid-related genes anthocyanidin synthase (ANS) and dihydroflavonol reductase (DFR) genes and also the reduction of the anthocyanin-related gene UDP glucose:flavonoid 3-O-glucosyl transferase (UFGT), which was dependent of the transgene expression. In addition, expression of VvMYB4-like in the model plant Arabidopsis showed similar results, with the higher down-regulation observed in the AtDFR and AtLDOX genes. These results suggest that VvMYB4-like may play an important role in regulation of anthocyanin biosynthesis in grapevine acting as a transcriptional repressor of flavonoid structural genes.

  17. Biologic and Therapeutic Significance of MYB Expression in Human Melanoma

    NASA Astrophysics Data System (ADS)

    Hijiya, Nobuko; Zhang, Jin; Ratajczak, Mariusz Z.; Kant, Jeffrey A.; Deriel, Kim; Herlyn, Meenhard; Zon, Gerald; Gewirtz, Alan M.

    1994-05-01

    We investigated the therapeutic potential of employing antisense oligodeoxynucleotides to target the disruption of MYB, a gene which has been postulated to play a pathogenetic role in cutaneous melanoma. We found that MYB was expressed at low levels in several human melanoma cell lines. Also, growth of representative lines in vitro was inhibited in a dose- and sequence-dependent manner by targeting the MYB gene with unmodified or phosphorothioate-modified antisense oligodeoxynucleotides. Inhibition of cell growth correlated with specific decrease of MYB mRNA. In SCID mice bearing human melanoma tumors, infusion of MYB antisense transiently suppressed MYB gene expression but effected long-term growth suppression of transplanted tumor cells. Toxicity of the oligodeoxynucleotides was minimal in mice, even when targeted to the murine Myb gene. These results suggest that the MYB gene may play an important, though undefined, role in the growth of at least some human melanomas. Inhibition of MYB expression might be of use in the treatment of this disease.

  18. Gene regulation networks generate diverse pigmentation patterns in plants.

    PubMed

    Albert, Nick W; Davies, Kevin M; Schwinn, Kathy E

    2014-01-01

    The diversity of pigmentation patterns observed in plants occurs due to the spatial distribution and accumulation of colored compounds, which may also be associated with structural changes to the tissue. Anthocyanins are flavonoids that provide red/purple/blue coloration to plants, often forming complex patterns such as spots, stripes, and vein-associated pigmentation, particularly in flowers. These patterns are determined by the activity of MYB-bHLH-WDR (MBW) transcription factor complexes, which activate the anthocyanin biosynthesis genes, resulting in anthocyanin pigment accumulation. Recently, we established that the MBW complex controlling anthocyanin synthesis acts within a gene regulation network that is conserved within at least the Eudicots. This network involves hierarchy, reinforcement, and feedback mechanisms that allow for stringent and responsive regulation of the anthocyanin biosynthesis genes. The gene network and mobile nature of the WDR and R3-MYB proteins provide exciting new opportunities to explore the basis of pigmentation patterning, and to investigate the evolutionary history of the MBW components in land plants.

  19. Structure of the Trichomonas vaginalis Myb3 DNA-binding domain bound to a promoter sequence reveals a unique C-terminal β-hairpin conformation.

    PubMed

    Wei, Shu-Yi; Lou, Yuan-Chao; Tsai, Jia-Yin; Ho, Meng-Ru; Chou, Chun-Chi; Rajasekaran, M; Hsu, Hong-Ming; Tai, Jung-Hsiang; Hsiao, Chwan-Deng; Chen, Chinpan

    2012-01-01

    Trichomonas vaginalis Myb3 transcription factor (tvMyb3) recognizes the MRE-1 promoter sequence and regulates ap65-1 gene, which encodes a hydrogenosomal malic enzyme that may play a role in the cytoadherence of the parasite. Here, we identified tvMyb3(53-180) as the essential fragment for DNA recognition and report the crystal structure of tvMyb3(53-180) bound to MRE-1 DNA. The N-terminal fragment adopts the classical conformation of an Myb DNA-binding domain, with the third helices of R2 and R3 motifs intercalating in the major groove of DNA. The C-terminal extension forms a β-hairpin followed by a flexible tail, which is stabilized by several interactions with the R3 motif and is not observed in other Myb proteins. Interestingly, this unique C-terminal fragment does not stably connect with DNA in the complex structure but is involved in DNA binding, as demonstrated by NMR chemical shift perturbation, (1)H-(15)N heteronuclear-nuclear Overhauser effect and intermolecular paramagnetic relaxation enhancement. Site-directed mutagenesis also revealed that this C-terminal fragment is crucial for DNA binding, especially the residue Arg(153) and the fragment K(170)KRK(173). We provide a structural basis for MRE-1 DNA recognition and suggest a possible post-translational regulation of tvMyb3 protein. PMID:21908401

  20. Novel bioresources for studies of Brassica oleracea: identification of a kale MYB transcription factor responsible for glucosinolate production.

    PubMed

    Araki, Ryoichi; Hasumi, Akiko; Nishizawa, Osamu Ishizaki; Sasaki, Katsunori; Kuwahara, Ayuko; Sawada, Yuji; Totoki, Yasushi; Toyoda, Atsushi; Sakaki, Yoshiyuki; Li, Yimeng; Saito, Kazuki; Ogawa, Toshiya; Hirai, Masami Yokota

    2013-10-01

    Plants belonging to the Brassicaceae family exhibit species-specific profiles of glucosinolates (GSLs), a class of defence compounds against pathogens and insects. GSLs also exhibit various human health-promoting properties. Among them, glucoraphanin (aliphatic 4-methylsulphinylbutyl GSL) has attracted the most attention because it hydrolyses to form a potent anticancer compound. Increased interest in developing commercial varieties of Brassicaceae crops with desirable GSL profiles has led to attempts to identify genes that are potentially valuable for controlling GSL biosynthesis. However, little attention has been focused on genes of kale (Brassica oleracea var. acephala). In this study, we established full-length kale cDNA libraries containing 59 904 clones, which were used to generate an expressed sequence tag (EST) data set with 119 204 entries. The EST data set clarified genes related to the GSL biosynthesis pathway in kale. We specifically focused on BoMYB29, a homolog of Arabidopsis MYB29/PMG2/HAG3, not only to characterize its function but also to demonstrate its usability as a biological resource. BoMYB29 overexpression in wild-type Arabidopsis enhanced the expression of aliphatic GSL biosynthetic genes and the accumulation of aliphatic GSLs. When expressed in the myb28myb29 mutant, which exhibited no detectable aliphatic GSLs, BoMYB29 restored the expression of biosynthetic genes and aliphatic GSL accumulation. Interestingly, the ratio of methylsulphinyl GSL content, including glucoraphanin, to that of methylthio GSLs was greatly increased, indicating the suitability of BoMYB29 as a regulator for increasing methylsulphinyl GSL content. Our results indicate that these biological resources can facilitate further identification of genes useful for modifications of GSL profiles and accumulation in kale.

  1. Identification and characterization of MYB-bHLH-WD40 regulatory complexes controlling proanthocyanidin biosynthesis in strawberry (Fragaria × ananassa) fruits.

    PubMed

    Schaart, Jan G; Dubos, Christian; Romero De La Fuente, Irene; van Houwelingen, Adèle M M L; de Vos, Ric C H; Jonker, Harry H; Xu, Wenjia; Routaboul, Jean-Marc; Lepiniec, Loïc; Bovy, Arnaud G

    2013-01-01

    Strawberry (Fragaria × ananassa) fruits contain high concentrations of flavonoids. In unripe strawberries, the flavonoids are mainly represented by proanthocyanidins (PAs), while in ripe fruits the red-coloured anthocyanins also accumulate. Most of the structural genes leading to PA biosynthesis in strawberry have been characterized, but no information is available on their transcriptional regulation. In Arabidopsis thaliana the expression of the PA biosynthetic genes is specifically induced by a ternary protein complex, composed of AtTT2 (AtMYB123), AtTT8 (AtbHLH042) and AtTTG1 (WD40-repeat protein). A strategy combining yeast-two-hybrid screening and agglomerative hierarchical clustering of transcriptomic and metabolomic data was undertaken to identify strawberry PA regulators. Among the candidate genes isolated, four were similar to AtTT2, AtTT8 and AtTTG1 (FaMYB9/FaMYB11, FabHLH3 and FaTTG1, respectively) and two encode putative negative regulators (FaMYB5 and FabHLH3∆). Interestingly, FaMYB9/FaMYB11, FabHLH3 and FaTTG1 were found to complement the tt2-1, tt8-3 and ttg1-1 transparent testa mutants, respectively. In addition, they interacted in yeast and activated the Arabidopsis BANYULS (anthocyanidin reductase) gene promoter when coexpressed in Physcomitrella patens protoplasts. Taken together, these results demonstrated that FaMYB9/FaMYB11, FabHLH3 and FaTTG1 are the respective functional homologues of AtTT2, AtTT8 and AtTTG1, providing new tools for modifying PA content and strawberry fruit quality.

  2. Identification and characterization of MYB-bHLH-WD40 regulatory complexes controlling proanthocyanidin biosynthesis in strawberry (Fragaria × ananassa) fruits.

    PubMed

    Schaart, Jan G; Dubos, Christian; Romero De La Fuente, Irene; van Houwelingen, Adèle M M L; de Vos, Ric C H; Jonker, Harry H; Xu, Wenjia; Routaboul, Jean-Marc; Lepiniec, Loïc; Bovy, Arnaud G

    2013-01-01

    Strawberry (Fragaria × ananassa) fruits contain high concentrations of flavonoids. In unripe strawberries, the flavonoids are mainly represented by proanthocyanidins (PAs), while in ripe fruits the red-coloured anthocyanins also accumulate. Most of the structural genes leading to PA biosynthesis in strawberry have been characterized, but no information is available on their transcriptional regulation. In Arabidopsis thaliana the expression of the PA biosynthetic genes is specifically induced by a ternary protein complex, composed of AtTT2 (AtMYB123), AtTT8 (AtbHLH042) and AtTTG1 (WD40-repeat protein). A strategy combining yeast-two-hybrid screening and agglomerative hierarchical clustering of transcriptomic and metabolomic data was undertaken to identify strawberry PA regulators. Among the candidate genes isolated, four were similar to AtTT2, AtTT8 and AtTTG1 (FaMYB9/FaMYB11, FabHLH3 and FaTTG1, respectively) and two encode putative negative regulators (FaMYB5 and FabHLH3∆). Interestingly, FaMYB9/FaMYB11, FabHLH3 and FaTTG1 were found to complement the tt2-1, tt8-3 and ttg1-1 transparent testa mutants, respectively. In addition, they interacted in yeast and activated the Arabidopsis BANYULS (anthocyanidin reductase) gene promoter when coexpressed in Physcomitrella patens protoplasts. Taken together, these results demonstrated that FaMYB9/FaMYB11, FabHLH3 and FaTTG1 are the respective functional homologues of AtTT2, AtTT8 and AtTTG1, providing new tools for modifying PA content and strawberry fruit quality. PMID:23157553

  3. Genome-wide classification and evolutionary and expression analyses of citrus MYB transcription factor families in sweet orange.

    PubMed

    Hou, Xiao-Jin; Li, Si-Bei; Liu, Sheng-Rui; Hu, Chun-Gen; Zhang, Jin-Zhi

    2014-01-01

    MYB family genes are widely distributed in plants and comprise one of the largest transcription factors involved in various developmental processes and defense responses of plants. To date, few MYB genes and little expression profiling have been reported for citrus. Here, we describe and classify 177 members of the sweet orange MYB gene (CsMYB) family in terms of their genomic gene structures and similarity to their putative Arabidopsis orthologs. According to these analyses, these CsMYBs were categorized into four groups (4R-MYB, 3R-MYB, 2R-MYB and 1R-MYB). Gene structure analysis revealed that 1R-MYB genes possess relatively more introns as compared with 2R-MYB genes. Investigation of their chromosomal localizations revealed that these CsMYBs are distributed across nine chromosomes. Sweet orange includes a relatively small number of MYB genes compared with the 198 members in Arabidopsis, presumably due to a paralog reduction related to repetitive sequence insertion into promoter and non-coding transcribed region of the genes. Comparative studies of CsMYBs and Arabidopsis showed that CsMYBs had fewer gene duplication events. Expression analysis revealed that the MYB gene family has a wide expression profile in sweet orange development and plays important roles in development and stress responses. In addition, 337 new putative microsatellites with flanking sequences sufficient for primer design were also identified from the 177 CsMYBs. These results provide a useful reference for the selection of candidate MYB genes for cloning and further functional analysis forcitrus.

  4. Genome-Wide Classification and Evolutionary and Expression Analyses of Citrus MYB Transcription Factor Families in Sweet Orange

    PubMed Central

    Hou, Xiao-Jin; Li, Si-Bei; Liu, Sheng-Rui; Hu, Chun-Gen; Zhang, Jin-Zhi

    2014-01-01

    MYB family genes are widely distributed in plants and comprise one of the largest transcription factors involved in various developmental processes and defense responses of plants. To date, few MYB genes and little expression profiling have been reported for citrus. Here, we describe and classify 177 members of the sweet orange MYB gene (CsMYB) family in terms of their genomic gene structures and similarity to their putative Arabidopsis orthologs. According to these analyses, these CsMYBs were categorized into four groups (4R-MYB, 3R-MYB, 2R-MYB and 1R-MYB). Gene structure analysis revealed that 1R-MYB genes possess relatively more introns as compared with 2R-MYB genes. Investigation of their chromosomal localizations revealed that these CsMYBs are distributed across nine chromosomes. Sweet orange includes a relatively small number of MYB genes compared with the 198 members in Arabidopsis, presumably due to a paralog reduction related to repetitive sequence insertion into promoter and non-coding transcribed region of the genes. Comparative studies of CsMYBs and Arabidopsis showed that CsMYBs had fewer gene duplication events. Expression analysis revealed that the MYB gene family has a wide expression profile in sweet orange development and plays important roles in development and stress responses. In addition, 337 new putative microsatellites with flanking sequences sufficient for primer design were also identified from the 177 CsMYBs. These results provide a useful reference for the selection of candidate MYB genes for cloning and further functional analysis forcitrus. PMID:25375352

  5. Regulated Gene Therapy.

    PubMed

    Breger, Ludivine; Wettergren, Erika Elgstrand; Quintino, Luis; Lundberg, Cecilia

    2016-01-01

    Gene therapy represents a promising approach for the treatment of monogenic and multifactorial neurological disorders. It can be used to replace a missing gene and mutated gene or downregulate a causal gene. Despite the versatility of gene therapy, one of the main limitations lies in the irreversibility of the process: once delivered to target cells, the gene of interest is constitutively expressed and cannot be removed. Therefore, efficient, safe and long-term gene modification requires a system allowing fine control of transgene expression.Different systems have been developed over the past decades to regulate transgene expression after in vivo delivery, either at transcriptional or post-translational levels. The purpose of this chapter is to give an overview on current regulatory system used in the context of gene therapy for neurological disorders. Systems using external regulation of transgenes using antibiotics are commonly used to control either gene expression using tetracycline-controlled transcription or protein levels using destabilizing domain technology. Alternatively, specific promoters of genes that are regulated by disease mechanisms, increasing expression as the disease progresses or decreasing expression as disease regresses, are also examined. Overall, this chapter discusses advantages and drawbacks of current molecular methods for regulated gene therapy in the central nervous system.

  6. Nitrogen depletion and small R3-MYB transcription factors affecting anthocyanin accumulation in Arabidopsis leaves.

    PubMed

    Nemie-Feyissa, Dugassa; Olafsdottir, Solveig Margret; Heidari, Behzad; Lillo, Cathrine

    2014-02-01

    Ternary complexes consisting of a R2R3-MYB, a bHLH and a WD40 protein (MBW complexes) regulate trichome formation and anthocyanin synthesis in plants. Small R3-MYBs interact with the MBW complexes to exert a negative feedback, and thereby participate in regulation of epidermal cell fate, for example trichome numbers and clustering in leaves. In Arabidopsis thaliana, GL3, a bHLH transcription factor, is important in the MBW complex regulating trichome formation as well as in the MBW complex induced by nitrogen depletion and promoting anthocyanin formation. The small R3-MYBs: CPC, TRY, ETC1, ETC2, ETC3/CPL3, TCL1, MYBL2, are all known to interact with GL3. We here investigated these R3-MYBs in leaves of Arabidopsis rosette stage plants under nitrogen depletion to examine if the small MYBs would interfere with anthocyanin accumulation in plants under normal (autotrophic) growth conditions. CPC expression was enhanced two-fold in response to nitrogen depletion, and ETC3/CPL3 expression was enhanced by almost an order of magnitude (9×). Knockout of ETC3/CPL3 did not influence anthocyanin accumulation, but the results establish ETC3/CPL3 as a nitrate regulated gene and a putative candidate for being involved in nitrate status signaling and root development. Other R3-MYBs tested were not significantly influenced by nitrogen depletion. In conclusion, only CPC expression increased and clearly exerted a negative feedback on anthocyanin accumulation during nitrogen starvation in rosette leaves. PMID:24388610

  7. Genome-Wide Identification and Analysis of the MYB Transcription Factor Superfamily in Solanum lycopersicum.

    PubMed

    Li, Zhenjun; Peng, Rihe; Tian, Yongsheng; Han, Hongjuan; Xu, Jing; Yao, Quanhong

    2016-08-01

    MYB proteins constitute one of the largest transcription factor families in the plant kingdom, members of which perform a variety of functions in plant biological processes. However, there are only very limited reports on the characterization of MYB transcription factors in tomato (Solanum lycopersicum). In our study, a total of 127 MYB genes have been identified in the tomato genome. A complete overview of these MYB genes is presented, including the phylogeny, gene structures, protein motifs, chromosome locations and expression patterns. The 127 SlMYB proteins could be classified into 18 subgroups based on domain similarity and phylogenetic topology. Phylogenetic analysis of SlMYBs along with MYBs from Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) indicated 14 subfamilies. Conserved motifs outside the MYB domain may reflect their functional conservation. The identified tomato MYB genes were distributed on 12 chromosomes at various densities but mainly in chromosomes 6 and 10 (12.6% and 11.8%, respectively). Genome-wide segmental and tandem duplications were also found, which may contribute to the expansion of SlMYB genes. RNA-sequencing and microarray data revealed tissue-specific and stress-responsive expression patterns of SlMYB genes. The expression profiles of SlMYB genes in response to salicylic acid (SA) and jasmonic acid methyl ester (MeJA) were also investigated by real-time PCR. Moreover, ethylene-responsive element-binding factor-associated amphiphilic repression (EAR) motifs were found in 24 SlMYB proteins. Collectively, our comprehensive analysis of SlMYB genes will facilitate future functional studies of the tomato MYB gene family and probably other Solanaceae plants. PMID:27279646

  8. Plant MYB Transcription Factors: Their Role in Drought Response Mechanisms

    PubMed Central

    Baldoni, Elena; Genga, Annamaria; Cominelli, Eleonora

    2015-01-01

    Water scarcity is one of the major causes of poor plant performance and limited crop yields worldwide and it is the single most common cause of severe food shortage in developing countries. Several molecular networks involved in stress perception, signal transduction and stress responses in plants have been elucidated so far. Transcription factors are major players in water stress signaling. In recent years, different MYB transcription factors, mainly in Arabidopsis thaliana (L.) Heynh. but also in some crops, have been characterized for their involvement in drought response. For some of them there is evidence supporting a specific role in response to water stress, such as the regulation of stomatal movement, the control of suberin and cuticular waxes synthesis and the regulation of flower development. Moreover, some of these genes have also been characterized for their involvement in other abiotic or biotic stresses, an important feature considering that in nature, plants are often simultaneously subjected to multiple rather than single environmental perturbations. This review summarizes recent studies highlighting the role of the MYB family of transcription factors in the adaptive responses to drought stress. The practical application value of MYBs in crop improvement, such as stress tolerance engineering, is also discussed. PMID:26184177

  9. Cutaneous cylindroma: it's all about MYB.

    PubMed

    Corda, Gabriele; Sala, Arturo

    2016-08-01

    Cutaneous cylindroma is a rare benign tumour that occasionally turns into malignant cylindrocarcinoma. The cancer can be sporadic or emerge in the context of Brooke-Spiegler syndrome (BSS), an inheritable condition characterized by mutation of the gene CYLD, encoding a tumour suppressor protein that controls the activity of the transcription factor NF-kB. Sporadic cylindromas present histological features shared with adenoid cystic carcinoma (ACC), a head and neck cancer originating from salivary or other exocrine glands. Like ACCs, sporadic cylindromas express, although at lower frequency, the aberrant fusion transcript MYB-NFIB. In a paper recently published in the Journal of Pathology, the research teams led by Neil Rajan and Goran Stenman demonstrate that CYLD-defective cyclindromas in BSS patients are negative for the MYB-NFIB fusion. Only the wild-type MYB oncoprotein is activated in the majority of these tumours. RNA interference studies in cells derived from BSS patients indicate that ablating MYB expression results in a striking reduction of cylindroma cell proliferation, suggesting that MYB plays a pivotal role in the biology of this cancer. The take-home message of the study is that activation of MYB, in its wild-type form or fusion derivatives, is a common feature of spontaneous and hereditary cylindromas, constituting a potentially actionable therapeutic target. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  10. Cloning and Characterization of a Putative R2R3 MYB Transcriptional Repressor of the Rosmarinic Acid Biosynthetic Pathway from Salvia miltiorrhiza

    PubMed Central

    Zhang, Shuncang; Ma, Pengda; Yang, Dongfeng; Li, Wenjing; Liang, Zongsuo; Liu, Yan; Liu, Fenghua

    2013-01-01

    Salvia miltiorrhiza Bunge is one of the most renowned traditional medicinal plants in China. Phenolic acids that are derived from the rosmarinic acid pathway, such as rosmarinic acid and salvianolic acid B, are important bioactive components in S. miltiorrhiza. Accumulations of these compounds have been reported to be induced by various elicitors, while little is known about transcription factors that function in their biosynthetic pathways. We cloned a subgroup 4 R2R3 MYB transcription factor gene (SmMYB39) from S. miltiorrhiza and characterized its roles through overexpression and RNAi-mediated silencing. As the results showed, the content of 4-coumaric acid, rosmarinic acid, salvianolic acid B, salvianolic acid A and total phenolics was dramatically decreased in SmMYB39-overexpressing S. miltiorrhiza lines while being enhanced by folds in SmMYB39-RNAi lines. Quantitative real-time PCR and enzyme activities analyses showed that SmMYB39 negatively regulated transcripts and enzyme activities of 4-hydroxylase (C4H) and tyrosine aminotransferase (TAT). These data suggest that SmMYB39 is involved in regulation of rosmarinic acid pathway and acts as a repressor through suppressing transcripts of key enzyme genes. PMID:24039895

  11. Overexpression of a R2R3 MYB gene MdSIMYB1 increases tolerance to multiple stresses in transgenic tobacco and apples.

    PubMed

    Wang, Rong-Kai; Cao, Zhong-Hui; Hao, Yu-Jin

    2014-01-01

    MYB transcription factors (TFs) involve in plant abiotic stress tolerance and response in various plant species. In this study, rapid amplification of cDNA ends (RACE) was conducted to isolate the R2R3-MYB TF gene MdSIMYB1 from apples (Malus × domestica). The gene transcripts were abundant in the leaves, flowers and fruits, compared to other organs, and were induced by abiotic stresses and plant hormones. We observed the subcellular localization of an MdSIMYB1-GFP fusion protein in the nucleus. Furthermore, the MdSIMYB1 gene was introduced into the tobacco genome and ectopically expressed in transgenic lines. The results indicate that MdSIMYB1 transgenic tobacco seed germination is insensitive to abscisic acid and NaCl treatment. Additionally, it was found that the ectopic expression of MdSIMYB1 enhanced the tolerance of plants to high salinity, drought and cold tolerance by upregulating the stress-responsive genes NtDREB1A, NtERD10B and NtERD10C. Meanwhile, the transgenic tobacco exhibited robust root growth because of the enhanced expression of the auxin-responsive genes NtIAA4.2, NtIAA4.1 and NtIAA2.5 under stress conditions, which is conducive to stress tolerance. Finally, transgenic apple lines were obtained and tested. Transgenic apple lines that were overexpressing MdSIMYB1 exhibited a higher tolerance to abiotic stress than the wild-type control, but suppression of MdSIMYB1 resulted in lower tolerance. Our results indicate that MdSIMYB1 may be utilized as a target gene for enhancing stress tolerance in important crops.

  12. BjMYB1, a transcription factor implicated in plant defence through activating BjCHI1 chitinase expression by binding to a W-box-like element

    PubMed Central

    Gao, Ying; Jia, Shuangwei; Wang, Chunlian; Wang, Fujun; Wang, Fajun; Zhao, Kaijun

    2016-01-01

    We previously identified the W-box-like-4 (Wbl-4) element (GTAGTGACTCAT), one of six Wbl elements in the BjC-P promoter of the unusual chitinase gene BjCHI1 from Brassica juncea, as the core element responsive to fungal infection. Here, we report the isolation and characterization of the cognate transcription factor interacting with the Wbl-4 element. Using Wbl-4 as a target, we performed yeast one-hybrid screening of a B. juncea cDNA library and isolated an R2R3-MYB transcription factor designated as BjMYB1. BjMYB1 was localized in the nucleus of plant cells. EMSA assays confirmed that BjMYB1 binds to the Wbl-4 element. Transiently expressed BjMYB1 up-regulated the activity of the BjC-P promoter through its binding to the Wbl-4 element in tobacco (Nicotiana benthamiana) leaves. In B. juncea, BjMYB1 displayed a similar induced expression pattern as that of BjCHI1 upon infection by the fungus Botrytis cinerea. Moreover, heterogeneous overexpression of BjMYB1 significantly elevated the resistance of transgenic Arabidopsis thaliana to the fungus B. cinerea. These results suggest that BjMYB1 is potentially involved in host defence against fungal attack through activating the expression of BjCHI1 by binding to the Wbl-4 element in the BjC-P promoter. This finding demonstrates a novel DNA target of plant MYB transcription factors. PMID:27353280

  13. Characterization of a New Pink-Fruited Tomato Mutant Results in the Identification of a Null Allele of the SlMYB12 Transcription Factor.

    PubMed

    Fernandez-Moreno, Josefina-Patricia; Tzfadia, Oren; Forment, Javier; Presa, Silvia; Rogachev, Ilana; Meir, Sagit; Orzaez, Diego; Aharoni, Aspah; Granell, Antonio

    2016-07-01

    The identification and characterization of new tomato (Solanum lycopersicum) mutants affected in fruit pigmentation and nutritional content can provide valuable insights into the underlying biology, as well as a source of new alleles for breeding programs. To date, all characterized pink-pigmented tomato fruit mutants appear to result from low SlMYB12 transcript levels in the fruit skin. Two new mutant lines displaying a pink fruit phenotype (pf1 and pf2) were characterized in this study. In the pf mutants, SlMYB12 transcripts accumulated to wild-type levels but exhibited the same truncation, which resulted in the absence of the essential MYB activation domain coding region. Allelism and complementation tests revealed that both pf mutants were allelic to the y locus and showed the same recessive null allele in homozygosis: Δy A set of molecular and metabolic effects, reminiscent of those observed in the Arabidopsis (Arabidopsis thaliana) myb11 myb12 myb111 triple mutant, were found in the tomato Δy mutants. To our knowledge, these have not been described previously, and our data support the idea of their being null mutants, in contrast to previously described transcriptional hypomorphic pink fruit lines. We detected a reduction in the expression of several flavonol glycosides and some associated glycosyl transferases. Transcriptome analysis further revealed that the effects of the pf mutations extended beyond the flavonoid pathway into the interface between primary and secondary metabolism. Finally, screening for Myb-binding sites in the candidate gene promoter sequences revealed that 141 of the 152 co-down-regulated genes may be direct targets of SlMYB12 regulation. PMID:27208285

  14. Characterization of a New Pink-Fruited Tomato Mutant Results in the Identification of a Null Allele of the SlMYB12 Transcription Factor.

    PubMed

    Fernandez-Moreno, Josefina-Patricia; Tzfadia, Oren; Forment, Javier; Presa, Silvia; Rogachev, Ilana; Meir, Sagit; Orzaez, Diego; Aharoni, Aspah; Granell, Antonio

    2016-07-01

    The identification and characterization of new tomato (Solanum lycopersicum) mutants affected in fruit pigmentation and nutritional content can provide valuable insights into the underlying biology, as well as a source of new alleles for breeding programs. To date, all characterized pink-pigmented tomato fruit mutants appear to result from low SlMYB12 transcript levels in the fruit skin. Two new mutant lines displaying a pink fruit phenotype (pf1 and pf2) were characterized in this study. In the pf mutants, SlMYB12 transcripts accumulated to wild-type levels but exhibited the same truncation, which resulted in the absence of the essential MYB activation domain coding region. Allelism and complementation tests revealed that both pf mutants were allelic to the y locus and showed the same recessive null allele in homozygosis: Δy A set of molecular and metabolic effects, reminiscent of those observed in the Arabidopsis (Arabidopsis thaliana) myb11 myb12 myb111 triple mutant, were found in the tomato Δy mutants. To our knowledge, these have not been described previously, and our data support the idea of their being null mutants, in contrast to previously described transcriptional hypomorphic pink fruit lines. We detected a reduction in the expression of several flavonol glycosides and some associated glycosyl transferases. Transcriptome analysis further revealed that the effects of the pf mutations extended beyond the flavonoid pathway into the interface between primary and secondary metabolism. Finally, screening for Myb-binding sites in the candidate gene promoter sequences revealed that 141 of the 152 co-down-regulated genes may be direct targets of SlMYB12 regulation.

  15. Characterization of Flavan-3-ols and Expression of MYB and Late Pathway Genes Involved in Proanthocyanidin Biosynthesis in Foliage of Vitis bellula

    PubMed Central

    Zhu, Yue; Peng, Qing-Zhong; Du, Ci; Li, Ke-Gang; Xie, De-Yu

    2013-01-01

    Proanthocyanidins (PAs) are fundamental nutritional metabolites in different types of grape products consumed by human beings. Although the biosynthesis of PAs in berry of Vitis vinifera has gained intensive investigations, the understanding of PAs in other Vitis species is limited. In this study, we report PA formation and characterization of gene expression involved in PA biosynthesis in leaves of V. bellula, a wild edible grape species native to south and south-west China. Leaves are collected at five developmental stages defined by sizes ranging from 0.5 to 5 cm in length. Analyses of thin layer chromatography (TLC) and high performance liquid chromatography-photodiode array detector (HPLC-PAD) show the formation of (+)-catechin, (−)-epicatechin, (+)-gallocatechin and (−)-epigallocatechin during the entire development of leaves. Analyses of butanol-HCl boiling cleavage coupled with spectrometry measurement at 550 nm show a temporal trend of extractable PA levels, which is characterized by an increase from 0.5 cm to 1.5 cm long leaves followed by a decrease in late stages. TLC and HPLC-PAD analyses identify cyanidin, delphinidin and pelargonidin produced from the cleavage of PAs in the butanol-HCl boiling, showing that the foliage PAs of V. bellula include three different types of extension units. Four cDNAs, which encode VbANR, VbDFR, VbLAR1 and VbLAR2, respectively, are cloned from young leaves. The expression patterns of VbANR and VbLAR2 but not VbLAR1 and VbDFR follow a similar trend as the accumulation patterns of PAs. Two cDNAs encoding VbMYBPA1 and VbMYB5a, the homologs of which have been demonstrated to regulate the expression of both ANR and LAR in V. vinifera, are also cloned and their expression profiles are similar to those of VbANR and VbLAR2. In contrast, the expression profiles of MYBA1 and 2 homologs involved in anthocyanin biosynthesis are different from those of VbANR and VbLAR2. Our data show that both ANR and LAR branches are involved in

  16. Control of trichome formation in Arabidopsis by poplar single-repeat R3 MYB transcription factors

    PubMed Central

    Zhou, Limei; Zheng, Kaijie; Wang, Xiaoyu; Tian, Hainan; Wang, Xianling; Wang, Shucai

    2014-01-01

    In Arabidopsis, trichome formation is regulated by the interplay of R3 MYBs and several others transcription factors including the WD40-repeat protein TRANSPARENT TESTA GLABRA1 (TTG1), the R2R3 MYB transcription factor GLABRA1 (GL1), the bHLH transcription factor GLABRA3 (GL3) or ENHANCER OF GLABRA3 (EGL3), and the homeodomain protein GLABRA2 (GL2). R3 MYBs including TRICHOMELESS1 (TCL1), TCL2, TRYPTICHON (TRY), CAPRICE (CPC), ENHANCER OF TRY AND CPC1 (ETC1), ETC2 and ETC3 negatively regulate trichome formation by competing with GL1 for binding GL3 or EGL3, thus blocking the formation of TTG1–GL3/EGL3–GL1, an activator complex required for the activation of the trichome positive regulator gene GL2. However, it is largely unknown if R3 MYBs in other plant species especially woody plants have similar functions. By BLASTing the Populus trichocarpa protein database using the entire amino acid sequence of TCL1, an Arabidopsis R3 MYB transcription factor, we identified a total of eight R3 MYB transcription factor genes in poplar, namely P. trichocarpa TRICHOMELESS1 through 8 (PtrTCL1–PtrTCL8). The amino acid signature required for interacting with bHLH transcription factors and the amino acids required for cell-to-cell movement of R3 MYBs are not fully conserved in all PtrTCLs. When tested in Arabidopsis protoplasts, however, all PtrTCLs interacted with GL3. Expressing each of the eight PtrTCL genes in Arabidopsis resulted in either glabrous phenotypes or plants with reduced trichome numbers, and expression levels of GL2 in all transgenic plants tested were greatly reduced. Expression of PtrTCL1 under the control of TCL1 native promoter almost completely complemented the mutant phenotype of tcl. In contrast, expression of PtrTCL1 under the control of TRY native promoter in the try mutant, or under the control of CPC native promoter in the cpc mutant resulted in glabrous phenotypes, suggesting that PtrTCL1 functions similarly to TCL1, but not TRY and CPC. PMID

  17. A Cotton MYB Transcription Factor, GbMYB5, is Positively Involved in Plant Adaptive Response to Drought Stress.

    PubMed

    Chen, Tianzi; Li, Wenjuan; Hu, Xuehong; Guo, Jiaru; Liu, Aimin; Zhang, Baolong

    2015-05-01

    Drought stress negatively affects plant growth and limits plant productivity. Genes functioning in plant responses to drought stress are essential for the development of drought-tolerant crops. Here, we report that an R2R3-type MYB transcription factor gene in Gossypium barbadense, GbMYB5, confers drought tolerance in cotton and transgenic tobacco. Virus-induced gene silencing of GbMYB5 compromised the tolerance of cotton plantlets to drought stress and reduced the post-rewatering water recovery survival rate to 50% as compared with the 90% survival rate in the wild type (WT). Silencing GbMYB5 decreased proline content and antioxidant enzyme activities and increased malondialdehyde (MDA) content in cotton under drought stress. The expression levels of drought-inducible genes NCED3, RD22 and RD26 were not affected by the silencing of GbMYB5. However, GbMYB5-overexpressing tobacco lines displayed hypersensitivity to ABA and improved survival rates as well as reduced water loss rates under drought stress. Furthermore, stomatal size and the rate of opening of stomata were markedly decreased in transgenic tobacco. The overexpression of GbMYB5 enhanced the accumulation of proline and antioxidant enzymes while it reduced production of MDA in transgenic tobacco as compared with the WT under drought stress. The transcript levels of the antioxidant genes SOD, CAT and GST, polyamine biosynthesis genes ADC1 and SAMDC, the late embryogenesis abundant protein-encoding gene ERD10D and drought-responsive genes NCED3, BG and RD26 were generally higher in GbMYB5-overexpressing tobacco than in the WT under drought stress. Collectively, our data suggested that GbMYB5 was positively involved in the plant adaptive response to drought stress. PMID:25657343

  18. A Cotton MYB Transcription Factor, GbMYB5, is Positively Involved in Plant Adaptive Response to Drought Stress.

    PubMed

    Chen, Tianzi; Li, Wenjuan; Hu, Xuehong; Guo, Jiaru; Liu, Aimin; Zhang, Baolong

    2015-05-01

    Drought stress negatively affects plant growth and limits plant productivity. Genes functioning in plant responses to drought stress are essential for the development of drought-tolerant crops. Here, we report that an R2R3-type MYB transcription factor gene in Gossypium barbadense, GbMYB5, confers drought tolerance in cotton and transgenic tobacco. Virus-induced gene silencing of GbMYB5 compromised the tolerance of cotton plantlets to drought stress and reduced the post-rewatering water recovery survival rate to 50% as compared with the 90% survival rate in the wild type (WT). Silencing GbMYB5 decreased proline content and antioxidant enzyme activities and increased malondialdehyde (MDA) content in cotton under drought stress. The expression levels of drought-inducible genes NCED3, RD22 and RD26 were not affected by the silencing of GbMYB5. However, GbMYB5-overexpressing tobacco lines displayed hypersensitivity to ABA and improved survival rates as well as reduced water loss rates under drought stress. Furthermore, stomatal size and the rate of opening of stomata were markedly decreased in transgenic tobacco. The overexpression of GbMYB5 enhanced the accumulation of proline and antioxidant enzymes while it reduced production of MDA in transgenic tobacco as compared with the WT under drought stress. The transcript levels of the antioxidant genes SOD, CAT and GST, polyamine biosynthesis genes ADC1 and SAMDC, the late embryogenesis abundant protein-encoding gene ERD10D and drought-responsive genes NCED3, BG and RD26 were generally higher in GbMYB5-overexpressing tobacco than in the WT under drought stress. Collectively, our data suggested that GbMYB5 was positively involved in the plant adaptive response to drought stress.

  19. Brassinosteroids control root epidermal cell fate via direct regulation of a MYB-bHLH-WD40 complex by GSK3-like kinases

    PubMed Central

    Cheng, Yinwei; Zhu, Wenjiao; Chen, Yuxiao; Ito, Shinsaku; Asami, Tadao; Wang, Xuelu

    2014-01-01

    In Arabidopsis, root hair and non-hair cell fates are determined by a MYB-bHLH-WD40 transcriptional complex and are regulated by many internal and environmental cues. Brassinosteroids play important roles in regulating root hair specification by unknown mechanisms. Here, we systematically examined root hair phenotypes in brassinosteroid-related mutants, and found that brassinosteroid signaling inhibits root hair formation through GSK3-like kinases or upstream components. We found that with enhanced brassinosteroid signaling, GL2, a cell fate marker for non-hair cells, is ectopically expressed in hair cells, while its expression in non-hair cells is suppressed when brassinosteroid signaling is reduced. Genetic analysis demonstrated that brassinosteroid-regulated root epidermal cell patterning is dependent on the WER-GL3/EGL3-TTG1 transcriptional complex. One of the GSK3-like kinases, BIN2, interacted with and phosphorylated EGL3, and EGL3s mutated at phosphorylation sites were retained in hair cell nuclei. BIN2 phosphorylated TTG1 to inhibit the activity of the WER-GL3/EGL3-TTG1 complex. Thus, our study provides insights into the mechanism of brassinosteroid regulation of root hair patterning. DOI: http://dx.doi.org/10.7554/eLife.02525.001 PMID:24771765

  20. The Eucalyptus grandis R2R3-MYB transcription factor family: evidence for woody growth-related evolution and function.

    PubMed

    Soler, Marçal; Camargo, Eduardo Leal Oliveira; Carocha, Victor; Cassan-Wang, Hua; San Clemente, Hélène; Savelli, Bruno; Hefer, Charles A; Paiva, Jorge A Pinto; Myburg, Alexander A; Grima-Pettenati, Jacqueline

    2015-06-01

    The R2R3-MYB family, one of the largest transcription factor families in higher plants, controls a wide variety of plant-specific processes including, notably, phenylpropanoid metabolism and secondary cell wall formation. We performed a genome-wide analysis of this superfamily in Eucalyptus, one of the most planted hardwood trees world-wide. A total of 141 predicted R2R3-MYB sequences identified in the Eucalyptus grandis genome sequence were subjected to comparative phylogenetic analyses with Arabidopsis thaliana, Oryza sativa, Populus trichocarpa and Vitis vinifera. We analysed features such as gene structure, conserved motifs and genome location. Transcript abundance patterns were assessed by RNAseq and validated by high-throughput quantitative PCR. We found some R2R3-MYB subgroups with expanded membership in E. grandis, V. vinifera and P. trichocarpa, and others preferentially found in woody species, suggesting diversification of specific functions in woody plants. By contrast, subgroups containing key genes regulating lignin biosynthesis and secondary cell wall formation are more conserved across all of the species analysed. In Eucalyptus, R2R3-MYB tandem gene duplications seem to disproportionately affect woody-preferential and woody-expanded subgroups. Interestingly, some of the genes belonging to woody-preferential subgroups show higher expression in the cambial region, suggesting a putative role in the regulation of secondary growth.

  1. Overexpression of SbMyb60 impacts phenylpropanoid biosynthesis and alters secondary cell wall composition in Sorghum bicolor.

    PubMed

    Scully, Erin D; Gries, Tammy; Sarath, Gautam; Palmer, Nathan A; Baird, Lisa; Serapiglia, Michelle J; Dien, Bruce S; Boateng, Akwasi A; Ge, Zhengxiang; Funnell-Harris, Deanna L; Twigg, Paul; Clemente, Thomas E; Sattler, Scott E

    2016-02-01

    The phenylpropanoid biosynthetic pathway that generates lignin subunits represents a significant target for altering the abundance and composition of lignin. The global regulators of phenylpropanoid metabolism may include MYB transcription factors, whose expression levels have been correlated with changes in secondary cell wall composition and the levels of several other aromatic compounds, including anthocyanins and flavonoids. While transcription factors correlated with downregulation of the phenylpropanoid biosynthesis pathway have been identified in several grass species, few transcription factors linked to activation of this pathway have been identified in C4 grasses, some of which are being developed as dedicated bioenergy feedstocks. In this study we investigated the role of SbMyb60 in lignin biosynthesis in sorghum (Sorghum bicolor), which is a drought-tolerant, high-yielding biomass crop. Ectopic expression of this transcription factor in sorghum was associated with higher expression levels of genes involved in monolignol biosynthesis, and led to higher abundances of syringyl lignin, significant compositional changes to the lignin polymer and increased lignin concentration in biomass. Moreover, transgenic plants constitutively overexpressing SbMyb60 also displayed ectopic lignification in leaf midribs and elevated concentrations of soluble phenolic compounds in biomass. Results indicate that overexpression of SbMyb60 is associated with activation of monolignol biosynthesis in sorghum. SbMyb60 represents a target for modification of plant cell wall composition, with the potential to improve biomass for renewable uses. PMID:26712107

  2. MYT3, A Myb-Like Transcription Factor, Affects Fungal Development and Pathogenicity of Fusarium graminearum

    PubMed Central

    Son, Hokyoung; Choi, Gyung Ja; Kim, Jin-Cheol; Lee, Yin-Won

    2014-01-01

    We previously characterized members of the Myb protein family, MYT1 and MYT2, in Fusarium graminearum. MYT1 and MYT2 are involved in female fertility and perithecium size, respectively. To expand knowledge of Myb proteins in F. graminearum, in this study, we characterized the functions of the MYT3 gene, which encodes a putative Myb-like transcription factor containing two Myb DNA-binding domains and is conserved in the subphylum Pezizomycotina of Ascomycota. MYT3 proteins were localized in nuclei during most developmental stages, suggesting the role of MYT3 as a transcriptional regulator. Deletion of MYT3 resulted in impairment of conidiation, germination, and vegetative growth compared to the wild type, whereas complementation of MYT3 restored the wild-type phenotype. Additionally, the Δmyt3 strain grew poorly on nitrogen-limited media; however, the mutant grew robustly on minimal media supplemented with ammonium. Moreover, expression level of nitrate reductase gene in the Δmyt3 strain was decreased in comparison to the wild type and complemented strain. On flowering wheat heads, the Δmyt3 strain exhibited reduced pathogenicity, which corresponded with significant reductions in trichothecene production and transcript levels of trichothecene biosynthetic genes. When the mutant was selfed, mated as a female, or mated as a male for sexual development, perithecia were not observed on the cultures, indicating that the Δmyt3 strain lost both male and female fertility. Taken together, these results demonstrate that MYT3 is required for pathogenesis and sexual development in F. graminearum, and will provide a robust foundation to establish the regulatory networks for all Myb-like proteins in F. graminearum. PMID:24722578

  3. Overexpression of AtMYB44 Enhances Stomatal Closure to Confer Abiotic Stress Tolerance in Transgenic Arabidopsis1[C][W][OA

    PubMed Central

    Jung, Choonkyun; Seo, Jun Sung; Han, Sang Won; Koo, Yeon Jong; Kim, Chung Ho; Song, Sang Ik; Nahm, Baek Hie; Choi, Yang Do; Cheong, Jong-Joo

    2008-01-01

    AtMYB44 belongs to the R2R3 MYB subgroup 22 transcription factor family in Arabidopsis (Arabidopsis thaliana). Treatment with abscisic acid (ABA) induced AtMYB44 transcript accumulation within 30 min. The gene was also activated under various abiotic stresses, such as dehydration, low temperature, and salinity. In transgenic Arabidopsis carrying an AtMYB44 promoter-driven β-glucuronidase (GUS) construct, strong GUS activity was observed in the vasculature and leaf epidermal guard cells. Transgenic Arabidopsis overexpressing AtMYB44 is more sensitive to ABA and has a more rapid ABA-induced stomatal closure response than wild-type and atmyb44 knockout plants. Transgenic plants exhibited a reduced rate of water loss, as measured by the fresh-weight loss of detached shoots, and remarkably enhanced tolerance to drought and salt stress compared to wild-type plants. Microarray analysis and northern blots revealed that salt-induced activation of the genes that encode a group of serine/threonine protein phosphatases 2C (PP2Cs), such as ABI1, ABI2, AtPP2CA, HAB1, and HAB2, was diminished in transgenic plants overexpressing AtMYB44. By contrast, the atmyb44 knockout mutant line exhibited enhanced salt-induced expression of PP2C-encoding genes and reduced drought/salt stress tolerance compared to wild-type plants. Therefore, enhanced abiotic stress tolerance of transgenic Arabidopsis overexpressing AtMYB44 was conferred by reduced expression of genes encoding PP2Cs, which have been described as negative regulators of ABA signaling. PMID:18162593

  4. Dynamic long-range chromatin interactions control Myb proto-oncogene transcription during erythroid development

    PubMed Central

    Stadhouders, Ralph; Thongjuea, Supat; Andrieu-Soler, Charlotte; Palstra, Robert-Jan; Bryne, Jan Christian; van den Heuvel, Anita; Stevens, Mary; de Boer, Ernie; Kockx, Christel; van der Sloot, Antoine; van den Hout, Mirjam; van IJcken, Wilfred; Eick, Dirk; Lenhard, Boris; Grosveld, Frank; Soler, Eric

    2012-01-01

    The key haematopoietic regulator Myb is essential for coordinating proliferation and differentiation. ChIP-Sequencing and Chromosome Conformation Capture (3C)-Sequencing were used to characterize the structural and protein-binding dynamics of the Myb locus during erythroid differentiation. In proliferating cells expressing Myb, enhancers within the Myb-Hbs1l intergenic region were shown to form an active chromatin hub (ACH) containing the Myb promoter and first intron. This first intron was found to harbour the transition site from transcription initiation to elongation, which takes place around a conserved CTCF site. Upon erythroid differentiation, Myb expression is downregulated and the ACH destabilized. We propose a model for Myb activation by distal enhancers dynamically bound by KLF1 and the GATA1/TAL1/LDB1 complex, which primarily function as a transcription elongation element through chromatin looping. PMID:22157820

  5. Dynamic long-range chromatin interactions control Myb proto-oncogene transcription during erythroid development.

    PubMed

    Stadhouders, Ralph; Thongjuea, Supat; Andrieu-Soler, Charlotte; Palstra, Robert-Jan; Bryne, Jan Christian; van den Heuvel, Anita; Stevens, Mary; de Boer, Ernie; Kockx, Christel; van der Sloot, Antoine; van den Hout, Mirjam; van Ijcken, Wilfred; Eick, Dirk; Lenhard, Boris; Grosveld, Frank; Soler, Eric

    2012-02-15

    The key haematopoietic regulator Myb is essential for coordinating proliferation and differentiation. ChIP-Sequencing and Chromosome Conformation Capture (3C)-Sequencing were used to characterize the structural and protein-binding dynamics of the Myb locus during erythroid differentiation. In proliferating cells expressing Myb, enhancers within the Myb-Hbs1l intergenic region were shown to form an active chromatin hub (ACH) containing the Myb promoter and first intron. This first intron was found to harbour the transition site from transcription initiation to elongation, which takes place around a conserved CTCF site. Upon erythroid differentiation, Myb expression is downregulated and the ACH destabilized. We propose a model for Myb activation by distal enhancers dynamically bound by KLF1 and the GATA1/TAL1/LDB1 complex, which primarily function as a transcription elongation element through chromatin looping. PMID:22157820

  6. Direct repression of MYB by ZEB1 suppresses proliferation and epithelial gene expression during epithelial-to-mesenchymal transition of breast cancer cells

    PubMed Central

    2013-01-01

    Introduction Epithelial-to-mesenchymal transition (EMT) promotes cell migration and is important in metastasis. Cellular proliferation is often downregulated during EMT, and the reverse transition (MET) in metastases appears to be required for restoration of proliferation in secondary tumors. We studied the interplay between EMT and proliferation control by MYB in breast cancer cells. Methods MYB, ZEB1, and CDH1 expression levels were manipulated by lentiviral small-hairpin RNA (shRNA)-mediated knockdown/overexpression, and verified with Western blotting, immunocytochemistry, and qRT-PCR. Proliferation was assessed with bromodeoxyuridine pulse labeling and flow cytometry, and sulforhodamine B assays. EMT was induced with epidermal growth factor for 9 days or by exposure to hypoxia (1% oxygen) for up to 5 days, and assessed with qRT-PCR, cell morphology, and colony morphology. Protein expression in human breast cancers was assessed with immunohistochemistry. ZEB1-MYB promoter binding and repression were determined with Chromatin Immunoprecipitation Assay and a luciferase reporter assay, respectively. Student paired t tests, Mann–Whitney, and repeated measures two-way ANOVA tests determined statistical significance (P < 0.05). Results Parental PMC42-ET cells displayed higher expression of ZEB1 and lower expression of MYB than did the PMC42-LA epithelial variant. Knockdown of ZEB1 in PMC42-ET and MDA-MB-231 cells caused increased expression of MYB and a transition to a more epithelial phenotype, which in PMC42-ET cells was coupled with increased proliferation. Indeed, we observed an inverse relation between MYB and ZEB1 expression in two in vitro EMT cell models, in matched human breast tumors and lymph node metastases, and in human breast cancer cell lines. Knockdown of MYB in PMC42-LA cells (MYBsh-LA) led to morphologic changes and protein expression consistent with an EMT. ZEB1 expression was raised in MYBsh-LA cells and significantly repressed in MYB

  7. New member of the R2R3-MYB transcription factors family in grapevine suppresses the anthocyanin accumulation in the flowers of transgenic tobacco.

    PubMed

    Pérez-Díaz, J Ricardo; Pérez-Díaz, Jorge; Madrid-Espinoza, José; González-Villanueva, Enrique; Moreno, Yerko; Ruiz-Lara, Simón

    2016-01-01

    In grapevine, anthocyanins and proanthocyanidins are the main flavonoids in berries, which are associated to organoleptic properties in red wine such as color and astringency. Flavonoid pathway is specifically regulated at transcriptional level and several R2R3-MYB proteins have shown to act as positive regulators. However, some members of this family have shown to repress the flavonoid biosynthesis. In this work, we present the characterization of VvMYB4-like gene, which encodes a putative transcriptional factor highly expressed in the skin of berries at the pre veraison stage in grapevine. Its over-expression in tobacco resulted in the loss of pigmentation in flowers due a decrease in anthocyanin accumulation. Severity in anthocyanin suppression observed in petals could be associated with the expression level of the VvMYB4-like transgene. Expression analysis of flavonoid structural genes revealed the strong down-regulation of the flavonoid-related genes anthocyanidin synthase (ANS) and dihydroflavonol reductase (DFR) genes and also the reduction of the anthocyanin-related gene UDP glucose:flavonoid 3-O-glucosyl transferase (UFGT), which was dependent of the transgene expression. In addition, expression of VvMYB4-like in the model plant Arabidopsis showed similar results, with the higher down-regulation observed in the AtDFR and AtLDOX genes. These results suggest that VvMYB4-like may play an important role in regulation of anthocyanin biosynthesis in grapevine acting as a transcriptional repressor of flavonoid structural genes. PMID:26497001

  8. Characterization and expression profiling of MYB transcription factors against stresses and during male organ development in Chinese cabbage (Brassica rapa ssp. pekinensis).

    PubMed

    Saha, Gopal; Park, Jong-In; Ahmed, Nasar Uddin; Kayum, Md Abdul; Kang, Kwon-Kyoo; Nou, Ill-Sup

    2016-07-01

    MYB proteins comprise a large family of plant transcription factors that play regulatory roles in different biological processes such as plant development, metabolism, and defense responses. To gain insight into this gene superfamily and to elucidate its roles in stress resistance, we performed a comprehensive genome-wide identification, characterization, and expression analysis of MYB genes in Chinese cabbage (Brassica rapa ssp. pekinensis). We identified 475 Chinese cabbage MYB genes, among which most were from R2R3-MYB (256 genes) and MYB-related (202) subfamilies. Analysis of sequence characteristics, phylogenetic classification, and protein motif structures confirmed the existence of several categories (1R, 2R, 3R, 4R, and 5R) of Chinese cabbage MYB genes, which is comparable with MYB genes of other crops. An extensive in silico functional analysis, based on established functional properties of MYB genes from different crop species, revealed 11 and four functional clades within the Chinese cabbage R2R3-MYB and MYB-related subfamilies, respectively. In this study, we reported a MYB-like group within the MYB-related subfamily contains 77 MYB genes. Expression analysis using low temperature-treated whole-genome microarray data revealed variable transcript abundance of 1R/2R/3R/4R/5R-MYB genes in 11 clusters between two inbred lines of Chinese cabbage, Chiifu and Kenshin, which differ in cold tolerance. In further validation tests, we used qRT-PCR to examine the cold-responsive expression patterns of 27 BrMYB genes; surprisingly, the MYB-related genes were induced more highly than the R2R3-MYB genes. In addition, we identified 10 genes with corresponsive expression patterns from a set of salt-, drought-, ABA-, JA-, and SA-induced R2R3-MYB genes. We identified 11 R2R3-MYBs functioning in resistance against biotic stress, including 10 against Fusarium oxysporum f.sp. conglutinans and one against Pectobacterium carotovoram subsp. caratovorum. Furthermore, based on

  9. Characterization and expression profiling of MYB transcription factors against stresses and during male organ development in Chinese cabbage (Brassica rapa ssp. pekinensis).

    PubMed

    Saha, Gopal; Park, Jong-In; Ahmed, Nasar Uddin; Kayum, Md Abdul; Kang, Kwon-Kyoo; Nou, Ill-Sup

    2016-07-01

    MYB proteins comprise a large family of plant transcription factors that play regulatory roles in different biological processes such as plant development, metabolism, and defense responses. To gain insight into this gene superfamily and to elucidate its roles in stress resistance, we performed a comprehensive genome-wide identification, characterization, and expression analysis of MYB genes in Chinese cabbage (Brassica rapa ssp. pekinensis). We identified 475 Chinese cabbage MYB genes, among which most were from R2R3-MYB (256 genes) and MYB-related (202) subfamilies. Analysis of sequence characteristics, phylogenetic classification, and protein motif structures confirmed the existence of several categories (1R, 2R, 3R, 4R, and 5R) of Chinese cabbage MYB genes, which is comparable with MYB genes of other crops. An extensive in silico functional analysis, based on established functional properties of MYB genes from different crop species, revealed 11 and four functional clades within the Chinese cabbage R2R3-MYB and MYB-related subfamilies, respectively. In this study, we reported a MYB-like group within the MYB-related subfamily contains 77 MYB genes. Expression analysis using low temperature-treated whole-genome microarray data revealed variable transcript abundance of 1R/2R/3R/4R/5R-MYB genes in 11 clusters between two inbred lines of Chinese cabbage, Chiifu and Kenshin, which differ in cold tolerance. In further validation tests, we used qRT-PCR to examine the cold-responsive expression patterns of 27 BrMYB genes; surprisingly, the MYB-related genes were induced more highly than the R2R3-MYB genes. In addition, we identified 10 genes with corresponsive expression patterns from a set of salt-, drought-, ABA-, JA-, and SA-induced R2R3-MYB genes. We identified 11 R2R3-MYBs functioning in resistance against biotic stress, including 10 against Fusarium oxysporum f.sp. conglutinans and one against Pectobacterium carotovoram subsp. caratovorum. Furthermore, based on

  10. Root hair formation at the root-hypocotyl junction in CPC-LIKE MYB double and triple mutants of Arabidopsis.

    PubMed

    Wada, Takuji; Hayashi, Naoto; Tominaga-Wada, Rumi

    2015-01-01

    In Arabidopsis thaliana, R3-type MYB genes, CAPRICE (CPC) and its family of genes including TRIPTYCHON (TRY), ENHANCER OF TRY AND CPC1 (ETC1), ETC2 and CPC-LIKE MYB3 cooperatively regulate epidermal cell differentiation. Root hair formation is greatly reduced by a mutation in CPC, and try and etc1 enhance this phenotype. In this study, we demonstrate that CPC, TRY and ETC1 are also involved in root hair formation at the root-hypocotyl junction. The cpc try and cpc etc1 double mutants showed a reduced number of root hairs in that area. Additionally, the expression of ETC1::GUS was higher near this area. These results suggest that CPC family of genes also cooperatively regulates root hair formation at the root-hypocotyl junction in unique ways.

  11. Root hair formation at the root-hypocotyl junction in CPC-LIKE MYB double and triple mutants of Arabidopsis

    PubMed Central

    Wada, Takuji; Hayashi, Naoto; Tominaga-Wada, Rumi

    2015-01-01

    In Arabidopsis thaliana, R3-type MYB genes, CAPRICE (CPC) and its family of genes including TRIPTYCHON (TRY), ENHANCER OF TRY AND CPC1 (ETC1), ETC2 and CPC-LIKE MYB3 cooperatively regulate epidermal cell differentiation. Root hair formation is greatly reduced by a mutation in CPC, and try and etc1 enhance this phenotype. In this study, we demonstrate that CPC, TRY and ETC1 are also involved in root hair formation at the root-hypocotyl junction. The cpc try and cpc etc1 double mutants showed a reduced number of root hairs in that area. Additionally, the expression of ETC1::GUS was higher near this area. These results suggest that CPC family of genes also cooperatively regulates root hair formation at the root-hypocotyl junction in unique ways. PMID:26339713

  12. The Phenylpropanoid Pathway Is Controlled at Different Branches by a Set of R2R3-MYB C2 Repressors in Grapevine1

    PubMed Central

    Cavallini, Erika; Matus, José Tomás; Finezzo, Laura; Zenoni, Sara; Loyola, Rodrigo; Guzzo, Flavia; Schlechter, Rudolf; Ageorges, Agnès; Arce-Johnson, Patricio

    2015-01-01

    Because of the vast range of functions that phenylpropanoids possess, their synthesis requires precise spatiotemporal coordination throughout plant development and in response to the environment. The accumulation of these secondary metabolites is transcriptionally controlled by positive and negative regulators from the MYB and basic helix-loop-helix protein families. We characterized four grapevine (Vitis vinifera) R2R3-MYB proteins from the C2 repressor motif clade, all of which harbor the ethylene response factor-associated amphiphilic repression domain but differ in the presence of an additional TLLLFR repression motif found in the strong flavonoid repressor Arabidopsis (Arabidopsis thaliana) AtMYBL2. Constitutive expression of VvMYB4a and VvMYB4b in petunia (Petunia hybrida) repressed general phenylpropanoid biosynthetic genes and selectively reduced the amount of small-weight phenolic compounds. Conversely, transgenic petunia lines expressing VvMYBC2-L1 and VvMYBC2-L3 showed a severe reduction in petal anthocyanins and seed proanthocyanidins together with a higher pH of crude petal extracts. The distinct function of these regulators was further confirmed by transient expression in tobacco (Nicotiana benthamiana) leaves and grapevine plantlets. Finally, VvMYBC2-L3 was ectopically expressed in grapevine hairy roots, showing a reduction in proanthocyanidin content together with the down-regulation of structural and regulatory genes of the flavonoid pathway as revealed by a transcriptomic analysis. The physiological role of these repressors was inferred by combining the results of the functional analyses and their expression patterns in grapevine during development and in response to ultraviolet B radiation. Our results indicate that VvMYB4a and VvMYB4b may play a key role in negatively regulating the synthesis of small-weight phenolic compounds, whereas VvMYBC2-L1 and VvMYBC2-L3 may additionally fine tune flavonoid levels, balancing the inductive effects of

  13. The phenylpropanoid pathway is controlled at different branches by a set of R2R3-MYB C2 repressors in grapevine.

    PubMed

    Cavallini, Erika; Matus, José Tomás; Finezzo, Laura; Zenoni, Sara; Loyola, Rodrigo; Guzzo, Flavia; Schlechter, Rudolf; Ageorges, Agnès; Arce-Johnson, Patricio; Tornielli, Giovanni Battista

    2015-04-01

    Because of the vast range of functions that phenylpropanoids possess, their synthesis requires precise spatiotemporal coordination throughout plant development and in response to the environment. The accumulation of these secondary metabolites is transcriptionally controlled by positive and negative regulators from the MYB and basic helix-loop-helix protein families. We characterized four grapevine (Vitis vinifera) R2R3-MYB proteins from the C2 repressor motif clade, all of which harbor the ethylene response factor-associated amphiphilic repression domain but differ in the presence of an additional TLLLFR repression motif found in the strong flavonoid repressor Arabidopsis (Arabidopsis thaliana) AtMYBL2. Constitutive expression of VvMYB4a and VvMYB4b in petunia (Petunia hybrida) repressed general phenylpropanoid biosynthetic genes and selectively reduced the amount of small-weight phenolic compounds. Conversely, transgenic petunia lines expressing VvMYBC2-L1 and VvMYBC2-L3 showed a severe reduction in petal anthocyanins and seed proanthocyanidins together with a higher pH of crude petal extracts. The distinct function of these regulators was further confirmed by transient expression in tobacco (Nicotiana benthamiana) leaves and grapevine plantlets. Finally, VvMYBC2-L3 was ectopically expressed in grapevine hairy roots, showing a reduction in proanthocyanidin content together with the down-regulation of structural and regulatory genes of the flavonoid pathway as revealed by a transcriptomic analysis. The physiological role of these repressors was inferred by combining the results of the functional analyses and their expression patterns in grapevine during development and in response to ultraviolet B radiation. Our results indicate that VvMYB4a and VvMYB4b may play a key role in negatively regulating the synthesis of small-weight phenolic compounds, whereas VvMYBC2-L1 and VvMYBC2-L3 may additionally fine tune flavonoid levels, balancing the inductive effects of

  14. The Expression of c-Myb Correlates with the Levels of Rhabdomyosarcoma-specific Marker Myogenin

    PubMed Central

    Kaspar, Petr; Zikova, Martina; Bartunek, Petr; Sterba, Jaroslav; Strnad, Hynek; Kren, Leos; Sedlacek, Radislav

    2015-01-01

    The transcription factor c-Myb is required for modulation of progenitor cells in several tissues, including skeletal muscle and its upregulation is observed in many human malignancies. Rhabdomyosarcomas (RMS) are a heterogeneous group of mesodermal tumors with features of developing skeletal muscle. Several miRNAs are downregulated in RMS, including miR-150, a negative regulator of c-Myb expression. Using the C2C12 myoblast cell line, a cellular model of skeletal muscle differentiation, we showed that miR-150 controls c-Myb expression mainly at the level of translation. We hypothesized that a similar mechanism of c-Myb regulation operates in RMS tumors. We examined expression of c-Myb by immunohistochemistry and revealed c-Myb positivity in alveolar and embryonal tumors, the two most common subgroups of RMS. Furthermore, we showed direct correlation between c-Myb production and myogenin expression. Interestingly, high myogenin levels indicate poor prognosis in RMS patients. c-Myb could, therefore, contribute to the tumor phenotype by executing its inhibitory role in skeletal muscle differentiation. We also showed that c-Myb protein is abundant in migratory C2C12 myoblasts and its ectopic expression potentiates cell motility. In summary, our results implicate that metastatic properties of some RMS subtypes might be linked to c-Myb function. PMID:26462877

  15. Changing a conserved amino acid in R2R3-MYB transcription repressors results in cytoplasmic accumulation and abolishes their repressive activity in Arabidopsis.

    PubMed

    Zhou, Meiliang; Sun, Zhanmin; Wang, Chenglong; Zhang, Xinquan; Tang, Yixiong; Zhu, Xuemei; Shao, Jirong; Wu, Yanmin

    2015-10-01

    Sub-group 4 R2R3-type MYB transcription factors, including MYB3, MYB4, MYB7 and MYB32, act as repressors in phenylpropanoid metabolism. These proteins contain the conserved MYB domain and the ethylene-responsive element binding factor-associated amphiphilic repression (EAR) repression domain. Additionally, MYB4, MYB7 and MYB32 possess a putative zinc-finger domain and a conserved GY/FDFLGL motif in their C-termini. The protein 'sensitive to ABA and drought 2' (SAD2) recognizes the nuclear pore complex, which then transports the SAD2-MYB4 complex into the nucleus. Here, we show that the conserved GY/FDFLGL motif contributes to the interaction between MYB factors and SAD2. The Asp → Asn mutation in the GY/FDFLGL motif abolishes the interaction between MYB transcription factors and SAD2, and therefore they cannot be transported into the nucleus and cannot repress their target genes. We found that MYB4(D261N) loses the capacity to repress expression of the cinnamate 4-hydroxylase (C4H) gene and biosynthesis of sinapoyl malate. Our results indicate conservation among MYB transcription factors in terms of their interaction with SAD2. Therefore, the Asp → Asn mutation may be used to engineer transcription factors. PMID:26332741

  16. vsiRNAs derived from the miRNA-generating sites of pri-tae-miR159a based on the BSMV system play positive roles in the wheat response to Puccinia striiformis f. sp. tritici through the regulation of taMyb3 expression.

    PubMed

    Feng, Hao; Zhang, Qiong; Li, Huayi; Wang, Xiaojie; Wang, Xiaodong; Duan, Xiaoyuan; Wang, Bing; Kang, Zhensheng

    2013-07-01

    Plants live in a complex environment, exposed to stresses, such as unsuitable climates, pests and pathogenic microorganisms. Pathogens are one of the most serious factors that threaten plant growth. Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases worldwide. Virus-induced gene silencing (VIGS) is a popular tool for the functional analysis of wheat genes, generating abundant small RNAs (sRNAs). sRNAs are key components in gene regulatory networks, silencing corresponding genes at the post-transcriptional level. In this study, we transduced pri-tae-miR159a into plant tissues using the barley stripe mosaic virus (BSMV) system, and demonstrated that vsiRNAs were generated from the same miRNAs generating sites of pri-tae-miR159a, with the function of Dicer RNase III-like classes of endonucleases (DCL4). In addition, the accumulation of vsiRNAs in wheat leaves challenged with Pst Chinese yellow rust 23 (CYR23), resulted in a resistant phenotype, and in the compatible interaction, the sporation of Pst was limited. Whereas, infection with a control construct had no effect on the resistance or susceptibility. The results of the histological observation also supported these phenotype changes. Interestingly, vsiRNAs were also involved in the interactions between wheat and Pst through the tae-miR159-mediated regulation of taMyb3 expression. Moreover, these results also supported the speculation that vsiRNAs were generated from the same sites of pri-tae-miR159a. These studies indicated that vsiRNAs from miRNAs generating sites of pri-tae-miR159a based on the BSMV system play positive roles in the wheat response to Pst through the regulation of taMyb3 expression.

  17. The Rice High-Affinity Potassium Transporter1;1 Is Involved in Salt Tolerance and Regulated by an MYB-Type Transcription Factor1[OPEN

    PubMed Central

    Wang, Rong; Jing, Wen; Jin, Yakang; Shen, Like

    2015-01-01

    Sodium transporters play key roles in plant tolerance to salt stress. Here, we report that a member of the High-Affinity K+ Transporter (HKT) family, OsHKT1;1, in rice (Oryza sativa ‘Nipponbare’) plays an important role in reducing Na+ accumulation in shoots to cope with salt stress. The oshkt1;1 mutant plants displayed hypersensitivity to salt stress. They contained less Na+ in the phloem sap and accumulated more Na+ in the shoots compared with the wild type. OsHKT1;1 was expressed mainly in the phloem of leaf blades and up-regulated in response to salt stress. Using a yeast one-hybrid approach, a novel MYB coiled-coil type transcription factor, OsMYBc, was found to bind to the OsHKT1;1 promoter. In vivo chromatin immunoprecipitation and in vitro electrophoresis mobility shift assays demonstrated that OsMYBc binds to AAANATNC(C/T) fragments within the OsHKT1;1 promoter. Mutation of the OsMYBc-binding nucleotides resulted in a decrease in promoter activity of OsHKT1;1. Knockout of OsMYBc resulted in a reduction in NaCl-induced expression of OsHKT1;1 and salt sensitivity. Taken together, these results suggest that OsHKT1;1 has a role in controlling Na+ concentration and preventing sodium toxicity in leaf blades and is regulated by the OsMYBc transcription factor. PMID:25991736

  18. Fbxw5 suppresses nuclear c-Myb activity via DDB1-Cul4-Rbx1 ligase-mediated sumoylation

    SciTech Connect

    Kanei-Ishii, Chie; Nomura, Teruaki; Egoh, Ayako; Ishii, Shunsuke

    2012-09-14

    Highlights: Black-Right-Pointing-Pointer Fbxw5 enhances sumoylation of c-Myb. Black-Right-Pointing-Pointer The DDB1-Cul4A-Rbx1 complex mediates c-Myb sumoylation. Black-Right-Pointing-Pointer The Fbxw5-DDB1-Cul4A-Rdx1 complex is a dual SUMO/ubiquitin ligase. Black-Right-Pointing-Pointer Fbxw5 suppresses the c-Myb trans-activating capacity. -- Abstract: The c-myb proto-oncogene product (c-Myb) is degraded in response to Wnt-1 signaling. In this process, Fbxw7{alpha}, the F-box protein of the SCF complex, binds to c-Myb via its C-terminal WD40 domain, and induces the ubiquitination of c-Myb. Here, we report that Fbxw5, another F-box protein, enhances sumoylation of nuclear c-Myb. Fbxw5 enhanced c-Myb sumoylation via the DDB1-Cul4A-Rbx1 complex. Since the Fbxw5-DDB1-Cul4A-Rbx1 complex was shown to act as a ubiquitin ligase for tumor suppressor TSC2, our results suggest that this complex can function as a dual SUMO/ubiquitin ligase. Fbxw5, which is localized to both nucleus and cytosol, enhanced sumoylation of nuclear c-Myb and induced the localization of c-Myb to nuclear dot-like domains. Co-expression of Fbxw5 suppressed the trans-activation of c-myc promoter by wild-type c-Myb, but not by v-Myb, which lacks the sumoylation sites. These results suggest that multiple E3 ligases suppress c-Myb activity through sumoylation or ubiquitination, and that v-Myb is no longer subject to these negative regulations.

  19. Flavonoid biosynthesis-related genes in grape skin are differentially regulated by temperature and light conditions.

    PubMed

    Azuma, Akifumi; Yakushiji, Hiroshi; Koshita, Yoshiko; Kobayashi, Shozo

    2012-10-01

    Temperature and light are important environmental factors that affect flavonoid biosynthesis in grape berry skin. However, the interrelationships between temperature and light effects on flavonoid biosynthesis have not been fully elucidated at the molecular level. Here, we investigated the effects of temperature and light conditions on the biosynthesis of flavonoids (anthocyanins and flavonols) and the expression levels of related genes in an in vitro environmental experiment using detached grape berries. Sufficient anthocyanin accumulation in the grape skin was observed under a low temperature (15 °C) plus light treatment, whereas high temperature (35 °C) or dark treatment severely suppressed anthocyanin accumulation. This indicates that the accumulation of anthocyanins is dependent on both low temperature and light. qRT-PCR analysis showed that the responses of three MYB-related genes (VlMYBA1-3, VlMYBA1-2, and VlMYBA2) to temperature and light differed greatly even though the products of all three genes had the ability to regulate anthocyanin biosynthesis pathway genes. Furthermore, the expression levels of other MYB-related genes and many flavonoid biosynthesis pathway genes were regulated independently by temperature and light. We also found that temperature and light conditions affected the anthocyanin composition in the skin through the regulation of flavonoid biosynthesis pathway genes. Our results suggest that low temperature and light have a synergistic effect on the expression of genes in the flavonoid biosynthesis pathway. These findings provide new information about the relationships between environmental factors and flavonoid accumulation in grape berry skin.

  20. Enhanced salt stress tolerance in transgenic potato plants expressing IbMYB1, a sweet potato transcription factor.

    PubMed

    Cheng, Yu-Jie; Kim, Myoung-Duck; Deng, Xi-Ping; Kwak, Sang-Soo; Chen, Wei

    2013-12-01

    IbMYB1, a transcription factor (TF) for R2R3-type MYB TFs, is a key regulator of anthocyanin biosynthesis during storage of sweet potatoes. Anthocyanins provide important antioxidants of nutritional value to humans, and also protect plants from oxidative stress. This study aimed to increase transgenic potatoes' (Solanum tuberosum cv. LongShu No.3) tolerance to environmental stress and enhance their nutritional value. Transgenic potato plants expressing IbMYB1 genes under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter (referred to as SM plants) were successfully generated through Agrobacterium-mediated transformation. Two representative transgenic SM5 and SM12 lines were evaluated for enhanced tolerance to salinity, UV-B rays, and drought conditions. Following treatment of 100 mM NaCl, seedlings of SM5 and SM12 lines showed less root damage and more shoot growth than control lines expressing only an empty vector. Transgenic potato plants in pots treated with 400 mM NaCl showed high amounts of secondary metabolites, including phenols, anthocyanins, and flavonoids, compared with control plants. After treatment of 400 mM NaCl, transgenic potato plants also showed high DDPH radical scavenging activity and high PS II photochemical efficiency compared with the control line. Furthermore, following treatment of NaCl, UV-B, and drought stress, the expression levels of IbMYB1 and several structural genes in the flavonoid biosynthesis such as CHS, DFR, and ANS in transgenic plants were found to be correlated with plant phenotype. The results suggest that enhanced IbMYB1 expression affects secondary metabolism, which leads to improved tolerance ability in transgenic potatoes.

  1. Enhanced salt stress tolerance in transgenic potato plants expressing IbMYB1, a sweet potato transcription factor.

    PubMed

    Cheng, Yu-Jie; Kim, Myoung-Duck; Deng, Xi-Ping; Kwak, Sang-Soo; Chen, Wei

    2013-12-01

    IbMYB1, a transcription factor (TF) for R2R3-type MYB TFs, is a key regulator of anthocyanin biosynthesis during storage of sweet potatoes. Anthocyanins provide important antioxidants of nutritional value to humans, and also protect plants from oxidative stress. This study aimed to increase transgenic potatoes' (Solanum tuberosum cv. LongShu No.3) tolerance to environmental stress and enhance their nutritional value. Transgenic potato plants expressing IbMYB1 genes under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter (referred to as SM plants) were successfully generated through Agrobacterium-mediated transformation. Two representative transgenic SM5 and SM12 lines were evaluated for enhanced tolerance to salinity, UV-B rays, and drought conditions. Following treatment of 100 mM NaCl, seedlings of SM5 and SM12 lines showed less root damage and more shoot growth than control lines expressing only an empty vector. Transgenic potato plants in pots treated with 400 mM NaCl showed high amounts of secondary metabolites, including phenols, anthocyanins, and flavonoids, compared with control plants. After treatment of 400 mM NaCl, transgenic potato plants also showed high DDPH radical scavenging activity and high PS II photochemical efficiency compared with the control line. Furthermore, following treatment of NaCl, UV-B, and drought stress, the expression levels of IbMYB1 and several structural genes in the flavonoid biosynthesis such as CHS, DFR, and ANS in transgenic plants were found to be correlated with plant phenotype. The results suggest that enhanced IbMYB1 expression affects secondary metabolism, which leads to improved tolerance ability in transgenic potatoes. PMID:24378636

  2. Transcriptional activation of a MYB gene controls the tissue-specific anthocyanin accumulation in a purple cauliflower mutant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavonoids such as anthocyanins possess significant health benefits to humans and play important physiological roles in plants. An interesting Purple gene mutation in cauliflower confers an abnormal pattern of anthocyanin accumulation, giving intense purple color in very young leaves, curds, and see...

  3. Molecular structure of the GARP family of plant Myb-related DNA binding motifs of the Arabidopsis response regulators.

    PubMed

    Hosoda, Kazuo; Imamura, Aya; Katoh, Etsuko; Hatta, Tomohisa; Tachiki, Mari; Yamada, Hisami; Mizuno, Takeshi; Yamazaki, Toshimasa

    2002-09-01

    The B motif is a signature of type-B response regulators (ARRs) involved in His-to-Asp phosphorelay signal transduction systems in Arabidopsis. Homologous motifs occur widely in the GARP family of plant transcription factors. To gain general insight into the structure and function of B motifs (or GARP motifs), we characterized the B motif derived from a representative ARR, ARR10, which led to a number of intriguing findings. First, the B motif of ARR10 (named ARR10-B and extending from Thr-179 to Ser-242) possesses a nuclear localization signal, as indicated by the intracellular localization of a green fluorescent protein-ARR10-B fusion protein in onion epidermal cells. Second, the purified ARR10-B molecule binds specifically in vitro to DNA with the core sequence AGATT. This was demonstrated by several in vitro approaches, including PCR-assisted DNA binding site selection, gel retardation assays, and surface plasmon resonance analysis. Finally, the three-dimensional structure of ARR10-B in solution was determined by NMR spectroscopy, showing that it contains a helix-turn-helix structure. Furthermore, the mode of interaction between ARR10-B and the target DNA was assessed extensively by NMR spectroscopy. Together, these results lead us to propose that the mechanism of DNA recognition by ARR10-B is essentially the same as that of homeodomains. We conclude that the B motif is a multifunctional domain responsible for both nuclear localization and DNA binding and suggest that these insights could be applicable generally to the large GARP family of plant transcription factors. PMID:12215502

  4. The genome sequence of the most widely cultivated cacao type and its use to identify candidate genes regulating pod color

    PubMed Central

    2013-01-01

    Background Theobroma cacao L. cultivar Matina 1-6 belongs to the most cultivated cacao type. The availability of its genome sequence and methods for identifying genes responsible for important cacao traits will aid cacao researchers and breeders. Results We describe the sequencing and assembly of the genome of Theobroma cacao L. cultivar Matina 1-6. The genome of the Matina 1-6 cultivar is 445 Mbp, which is significantly larger than a sequenced Criollo cultivar, and more typical of other cultivars. The chromosome-scale assembly, version 1.1, contains 711 scaffolds covering 346.0 Mbp, with a contig N50 of 84.4 kbp, a scaffold N50 of 34.4 Mbp, and an evidence-based gene set of 29,408 loci. Version 1.1 has 10x the scaffold N50 and 4x the contig N50 as Criollo, and includes 111 Mb more anchored sequence. The version 1.1 assembly has 4.4% gap sequence, while Criollo has 10.9%. Through a combination of haplotype, association mapping and gene expression analyses, we leverage this robust reference genome to identify a promising candidate gene responsible for pod color variation. We demonstrate that green/red pod color in cacao is likely regulated by the R2R3 MYB transcription factor TcMYB113, homologs of which determine pigmentation in Rosaceae, Solanaceae, and Brassicaceae. One SNP within the target site for a highly conserved trans-acting siRNA in dicots, found within TcMYB113, seems to affect transcript levels of this gene and therefore pod color variation. Conclusions We report a high-quality sequence and annotation of Theobroma cacao L. and demonstrate its utility in identifying candidate genes regulating traits. PMID:23731509

  5. Nutritional regulation of gene expression.

    PubMed

    Cousins, R J

    1999-01-25

    Genes are regulated by complex arrays of response elements that influence the rate of transcription. Nutrients and hormones either act directly to influence these rates or act indirectly through specialized signaling pathways. Metabolites of vitamins A and D, fatty acids, some sterols, and zinc are among the nutrients that influence transcription directly. Components of dietary fiber may influence gene expression indirectly through changes in hormonal signaling, mechanical stimuli, and metabolites produced by the intestinal microflora. In addition, consumption of water-soluble fibers may lead to changes in gene expression mediated through indirect mechanisms that influence transcription rates. In the large intestine, short-chain fatty acids, including butyric acid, are produced by microflora. Butyric acid can indirectly influence gene expression. Some sources of fiber limit nutrient absorption, particularly of trace elements. This could have direct or indirect effects on gene expression. Identification of genes in colonic epithelial cells that are differentially regulated by dietary fiber will be an important step toward understanding the role of dietary factors in colorectal cancer progression.

  6. Shoot Branching and Leaf Dissection in Tomato Are Regulated by Homologous Gene Modules[W

    PubMed Central

    Busch, Bernhard L.; Schmitz, Gregor; Rossmann, Susanne; Piron, Florence; Ding, Jia; Bendahmane, Abdelhafid; Theres, Klaus

    2011-01-01

    Aerial plant architecture is predominantly determined by shoot branching and leaf morphology, which are governed by apparently unrelated developmental processes, axillary meristem formation, and leaf dissection. Here, we show that in tomato (Solanum lycopersicum), these processes share essential functions in boundary establishment. Potato leaf (C), a key regulator of leaf dissection, was identified to be the closest paralog of the shoot branching regulator Blind (Bl). Comparative genomics revealed that these two R2R3 MYB genes are orthologs of the Arabidopsis thaliana branching regulator REGULATOR OF AXILLARY MERISTEMS1 (RAX1). Expression studies and complementation analyses indicate that these genes have undergone sub- or neofunctionalization due to promoter differentiation. C acts in a pathway independent of other identified leaf dissection regulators. Furthermore, the known leaf complexity regulator Goblet (Gob) is crucial for axillary meristem initiation and acts in parallel to C and Bl. Finally, RNA in situ hybridization revealed that the branching regulator Lateral suppressor (Ls) is also expressed in leaves. All four boundary genes, C, Bl, Gob, and Ls, may act by suppressing growth, as indicated by gain-of-function plants. Thus, leaf architecture and shoot architecture rely on a conserved mechanism of boundary formation preceding the initiation of leaflets and axillary meristems. PMID:22039213

  7. A novel MYB transcription factor, GmMYBJ1, from soybean confers drought and cold tolerance in Arabidopsis thaliana.

    PubMed

    Su, Lian-Tai; Li, Jing-Wen; Liu, De-Quan; Zhai, Ying; Zhang, Hai-Jun; Li, Xiao-Wei; Zhang, Qing-Lin; Wang, Ying; Wang, Qing-Yu

    2014-03-15

    MYB transcription factors play important roles in the regulation of plant growth, developmental metabolism and stress responses. In this study, a new MYB transcription factor gene, GmMYBJ1, was isolated from soybean [Glycine max (L.)]. The GmMYBJ1 cDNA is 1296bp in length with an open reading frame (ORF) of 816 bp encoding for 271 amino acids. The amino acid sequence displays similarities to the typical R2R3 MYB proteins reported in other plants. Transient expression analysis using the GmMYBJ1-GFP fusion gene in onion epidermal cells revealed that the GmMYBJ1 protein is targeted to the nucleus. Quantitative RT-PCR analysis demonstrated that GmMYBJ1 expression was induced by abiotic stresses, such as drought, cold, salt and exogenous abscisic acid (ABA). Compared to wild-type (WT) plants, transgenic Arabidopsis overexpressing GmMYBJ1 exhibited an enhanced tolerance to drought and cold stresses. These results indicate that GmMYBJ1 has the potential to be utilized in transgenic breeding lines to improve abiotic stress tolerance.

  8. Homotypic clustering of OsMYB4 binding site motifs in promoters of the rice genome and cellular-level implications on sheath blight disease resistance.

    PubMed

    Pooja, Singh; Sweta, Kumari; Mohanapriya, A; Sudandiradoss, C; Siva, Ramamoorthy; Gothandam, Kodiveri M; Babu, Subramanian

    2015-05-01

    The promoter regions (1 kb upstream sequences) of 45,836 annotated genes of rice were analyzed for the presence of OsMYB4 binding sites using a Perl program algorithm. Based on the homotypic clustering concept, 113 promoters were found to have more than 4 binding site motifs. Among the downstream genes of these promoters, five genes which are known to have a role in disease resistance were selected and the binding capacity of OsMYB4 protein in the promoter regions was analyzed by docking studies. Expression level of these genes was analyzed by RT-PCR in Rhizoctonia solani infected rice seedlings. Upon pathogen challenge, higher expression of aminotransferase, ankyrin and WRKY 12 genes was observed corresponding to higher expression of Osmyb4. Over-expression of Osmyb4 cDNA in rice leaf tissues by agro-infection failed to result in similar over-expression of aminotransferase, ankyrin and WRKY 12 as expected. Although the role of OsMYB4 in sheath blight resistance was found to be definitive based on our initial results, artificial over-expression of this TF was observed to be insufficient in regulating the disease resistance related genes.

  9. MYB8 Controls Inducible Phenolamide Levels by Activating Three Novel Hydroxycinnamoyl-Coenzyme A:Polyamine Transferases in Nicotiana attenuata[W][OA

    PubMed Central

    Onkokesung, Nawaporn; Gaquerel, Emmanuel; Kotkar, Hemlata; Kaur, Harleen; Baldwin, Ian T.; Galis, Ivan

    2012-01-01

    A large number of plants accumulate N-acylated polyamines (phenolamides [PAs]) in response to biotic and/or abiotic stress conditions. In the native tobacco (Nicotiana attenuata), the accumulation of two major PAs, caffeoylputrescine and dicaffeoylspermidine (DCS), after herbivore attack is known to be controlled by a key transcription factor, MYB8. Using a broadly targeted metabolomics approach, we show that a much larger spectrum of PAs composed of hydroxycinnamic acids and two polyamines, putrescine and spermidine, is regulated by this transcription factor. We cloned several novel MYB8-regulated genes, annotated as putative acyltransferases, and analyzed their function. One of the novel acyltransferases (AT1) is shown to encode a hydroxycinnamoyl-coenzyme A:putrescine acyltransferase responsible for caffeoylputrescine biosynthesis in tobacco. Another gene (acyltransferase DH29), specific for spermidine conjugation, mediates the initial acylation step in DCS formation. Although this enzyme was not able to perform the second acylation toward DCS biosynthesis, another acyltransferase gene, CV86, proposed to act on monoacylated spermidines, was isolated and partially characterized. The activation of MYB8 in response to herbivore attack and associated signals required the activity of LIPOXYGENASE3, a gene involved in jasmonic acid (JA) biosynthesis in N. attenuata. These new results allow us to reconstruct a complete branch in JA signaling that defends N. attenuata plants against herbivores: JA via MYB8’s transcriptional control of AT1 and DH29 genes controls the entire branch of PA biosynthesis, which allows N. attenuata to mount a chemically diverse (and likely efficient) defense shield against herbivores. PMID:22082505

  10. Gene regulation by mechanical forces

    NASA Technical Reports Server (NTRS)

    Oluwole, B. O.; Du, W.; Mills, I.; Sumpio, B. E.

    1997-01-01

    Endothelial cells are subjected to various mechanical forces in vivo from the flow of blood across the luminal surface of the blood vessel. The purpose of this review was to examine the data available on how these mechanical forces, in particular cyclic strain, affect the expression and regulation of endothelial cell function. Studies from various investigators using models of cyclic strain in vitro have shown that various vasoactive mediators such as nitric oxide and prostacyclin are induced by the effect of mechanical deformation, and that the expression of these mediators may be regulated at the transcription level by mechanical forces. There also seems to be emerging evidence that endothelial cells may also act as mechanotransducers, whereby the transmission of external forces induces various cytoskeletal changes and second messenger cascades. Furthermore, it seems these forces may act on specific response elements of promoter genes.

  11. QB1 - Stochastic Gene Regulation

    SciTech Connect

    Munsky, Brian

    2012-07-23

    Summaries of this presentation are: (1) Stochastic fluctuations or 'noise' is present in the cell - Random motion and competition between reactants, Low copy, quantization of reactants, Upstream processes; (2) Fluctuations may be very important - Cell-to-cell variability, Cell fate decisions (switches), Signal amplification or damping, stochastic resonances; and (3) Some tools are available to mode these - Kinetic Monte Carlo simulations (SSA and variants), Moment approximation methods, Finite State Projection. We will see how modeling these reactions can tell us more about the underlying processes of gene regulation.

  12. Mathematical Models of Gene Regulation

    NASA Astrophysics Data System (ADS)

    Mackey, Michael C.

    2004-03-01

    This talk will focus on examples of mathematical models for the regulation of repressible operons (e.g. the tryptophan operon), inducible operons (e.g. the lactose operon), and the lysis/lysogeny switch in phage λ. These ``simple" gene regulatory elements can display characteristics experimentally of rapid response to perturbations and bistability, and biologically accurate mathematical models capture these aspects of the dynamics. The models, if realistic, are always nonlinear and contain significant time delays due to transcriptional and translational delays that pose substantial problems for the analysis of the possible ranges of dynamics.

  13. Sucrose prevents up-regulation of senescence-associated genes in carnation petals.

    PubMed

    Hoeberichts, Frank A; van Doorn, Wouter G; Vorst, Oscar; Hall, Robert D; van Wordragen, Monique F

    2007-01-01

    cDNA microarrays were used to characterize senescence-associated gene expression in petals of cut carnation (Dianthus caryophyllus) flowers, sampled from anthesis to the first senescence symptoms. The population of PCR fragments spotted on these microarrays was enriched for flower-specific and senescence-specific genes, using subtractive hybridization. About 90% of the transcripts showed a large increase in quantity, approximately 25% transiently, and about 65% throughout the 7 d experiment. Treatment with silver thiosulphate (STS), which blocks the ethylene receptor and prevented the normal senescence symptoms, prevented the up-regulation of almost all of these genes. Sucrose treatment also considerably delayed visible senescence. Its effect on gene expression was very similar to that of STS, suggesting that soluble sugars act as a repressor of ethylene signal transduction. Two fragments that encoded a carnation EIN3-like (EIL) protein were isolated, some of which are key transcription factors that control ethylene response genes. One of these (Dc-EIL3) was up-regulated during senescence. Its up-regulation was delayed by STS and prevented by sucrose. Sucrose, therefore, seems to repress ethylene signalling, in part, by preventing up-regulation of Dc-EIL3. Some other transcription factors displayed an early increase in transcript abundance: a MYB-like DNA binding protein, a MYC protein, a MADS-box factor, and a zinc finger protein. Genes suggesting a role in senescence of hormones other than ethylene encoded an Aux/IAA protein, which regulate transcription of auxin-induced genes, and a cytokinin oxidase/dehydrogenase, which degrades cytokinin. Taken together, the results suggest a master switch during senescence, controlling the co-ordinated up-regulation of numerous ethylene response genes. Dc-EIL3 might be (part of) this master switch.

  14. Characterization of the cis elements in the proximal promoter regions of the anthocyanin pathway genes reveals a common regulatory logic that governs pathway regulation

    PubMed Central

    Zhu, Zhixin; Wang, Hailong; Wang, Yiting; Guan, Shan; Wang, Fang; Tang, Jingyu; Zhang, Ruijuan; Xie, Lulu; Lu, Yingqing

    2015-01-01

    Cellular activities such as compound synthesis often require the transcriptional activation of an entire pathway; however, the molecular mechanisms underlying pathway activation have rarely been explained. Here, the cis regulatory architecture of the anthocyanin pathway genes targeted by the transcription factor (TF) complex including MYB, bHLH, and WDR was systematically analysed in one species and the findings extended to others. In Ipomoea purpurea, the IpMYB1-IpbHLH2-IpWDR1 (IpMBW) complex was found to be orthologous to the PAP1-GL3-TTG1 (AtPGT) complex of Arabidopsis thaliana, and interacted with a 7-bp MYB-recognizing element (MRE) and a 6-bp bHLH-recognizing element (BRE) at the proximal promoter region of the pathway genes. There was little transcription of the gene in the absence of the MRE or BRE. The cis elements identified experimentally converged on two syntaxes, ANCNNCC for MREs and CACN(A/C/T)(G/T) for BREs, and our bioinformatic analysis showed that these were present within anthocyanin gene promoters in at least 35 species, including both gymnosperms and angiosperms. For the anthocyanin pathway, IpMBW and AtPGT recognized the interspecific promoters of both early and later genes. In A. thaliana, the seed-specific TF complex (TT2, TT8, and TTG1) may regulate all the anthocyanin pathway genes, in addition to the proanthocyanidin-specific BAN. When multiple TF complexes in the anthocyanin pathway were compared, the cis architecture played a role larger than the TF complex in determining the variation in promoter activity. Collectively, a cis logic common to the pathway gene promoters was found, and this logic is essential for the trans factors to regulate the pathway. PMID:25911741

  15. A subcellular tug of war involving three MYB-like proteins underlies a molecular antagonism in Antirrhinum flower asymmetry.

    PubMed

    Raimundo, João; Sobral, Rómulo; Bailey, Paul; Azevedo, Herlânder; Galego, Lisete; Almeida, Jorge; Coen, Enrico; Costa, Maria Manuela R

    2013-08-01

    The establishment of meristematic domains with different transcriptional activity is essential for many developmental processes. The asymmetry of the Antirrhinum majus flower is established by transcription factors with an asymmetric pattern of activity. To understand how this asymmetrical pattern is established, we studied the molecular mechanism through which the dorsal MYB protein RADIALIS (RAD) restricts the activity of the MYB transcription factor DIVARICATA (DIV) to the ventral region of the flower meristem. We show that RAD competes with DIV for binding with other MYB-like proteins, termed DRIF1 and DRIF2 (DIV- and-RAD-interacting-factors). DRIF1 and DIV interact to form a protein complex that binds to the DIV-DNA consensus region, suggesting that the DRIFs act as co-regulators of DIV transcriptional activity. In the presence of RAD, the interaction between DRIF1 and DIV bound to DNA is disrupted. Moreover, the DRIFs are sequestered in the cytoplasm by RAD, thus, preventing or reducing the formation of DRIF-DIV heterodimers in the nuclei. Our results suggest that in the dorsal region of the Antirrhinum flower meristem the dorsal protein RAD antagonises the activity of the ventral identity protein DIV in a subcellular competition for a DRIF protein promoting the establishment of the asymmetric pattern of gene activity in the Antirrhinum flower.

  16. Low glutathione regulates gene expression and the redox potentials of the nucleus and cytosol in Arabidopsis thaliana.

    PubMed

    Schnaubelt, Daniel; Queval, Guillaume; Dong, Yingping; Diaz-Vivancos, Pedro; Makgopa, Matome Eugene; Howell, Gareth; De Simone, Ambra; Bai, Juan; Hannah, Matthew A; Foyer, Christine H

    2015-02-01

    Reduced glutathione (GSH) is considered to exert a strong influence on cellular redox homeostasis and to regulate gene expression, but these processes remain poorly characterized. Severe GSH depletion specifically inhibited root meristem development, while low root GSH levels decreased lateral root densities. The redox potential of the nucleus and cytosol of Arabidopsis thaliana roots determined using roGFP probes was between -300 and -320 mV. Growth in the presence of the GSH-synthesis inhibitor buthionine sulfoximine (BSO) increased the nuclear and cytosolic redox potentials to approximately -260 mV. GSH-responsive genes including transcription factors (SPATULA, MYB15, MYB75), proteins involved in cell division, redox regulation (glutaredoxinS17, thioredoxins, ACHT5 and TH8) and auxin signalling (HECATE), were identified in the GSH-deficient root meristemless 1-1 (rml1-1) mutant, and in other GSH-synthesis mutants (rax1-1, cad2-1, pad2-1) as well as in the wild type following the addition of BSO. Inhibition of auxin transport had no effect on organ GSH levels, but exogenous auxin decreased the root GSH pool. We conclude that GSH depletion significantly increases the redox potentials of the nucleus and cytosol, and causes arrest of the cell cycle in roots but not shoots, with accompanying transcript changes linked to altered hormone responses, but not oxidative stress.

  17. Transcriptional regulation of tenascin genes

    PubMed Central

    Chiovaro, Francesca; Chiquet-Ehrismann, Ruth; Chiquet, Matthias

    2015-01-01

    Extracellular matrix proteins of the tenascin family resemble each other in their domain structure, and also share functions in modulating cell adhesion and cellular responses to growth factors. Despite these common features, the 4 vertebrate tenascins exhibit vastly different expression patterns. Tenascin-R is specific to the central nervous system. Tenascin-C is an “oncofetal” protein controlled by many stimuli (growth factors, cytokines, mechanical stress), but with restricted occurrence in space and time. In contrast, tenascin-X is a constituitive component of connective tissues, and its level is barely affected by external factors. Finally, the expression of tenascin-W is similar to that of tenascin-C but even more limited. In accordance with their highly regulated expression, the promoters of the tenascin-C and -W genes contain TATA boxes, whereas those of the other 2 tenascins do not. This article summarizes what is currently known about the complex transcriptional regulation of the 4 tenascin genes in development and disease. PMID:25793574

  18. Transposon insertions in the promoter of the Zea mays a1 gene differentially affect transcription by the Myb factors P and C1.

    PubMed Central

    Pooma, Wilailak; Gersos, Christos; Grotewold, Erich

    2002-01-01

    The understanding of control of gene regulation in higher eukaryotes relies heavily on results derived from non-in vivo studies, but rarely can the significance of these approximations be established in vivo. Here, we investigated the effect of Mutator and Spm insertions on the expression of the flavonoid biosynthetic gene a1, independently regulated by the transcription factors C1 and P. The a1-mum2 and a1-m2 alleles carry Mu1 and Spm insertions, respectively, in a cis-element (ARE) of unknown function located between the P- and C1-binding sites. We show that the insertions of Mu1 and Spm similarly influence the expression of a1 controlled by C1 or P. The P-controlled a1 expression in a1-m2 is Spm dependent, and the mutant phenotype of a1-mum2 is suppressed in the pericarp in the absence of the autonomous MuDR element. Footprints within the ARE affect the regulation of a1 by C1 and P differently, providing evidence that these factors control a1 expression using distinct cis-acting regulatory elements. Together, our findings contribute significantly to one of the best-described plant regulatory systems, while stressing the need to complement with in vivo experiments current approaches used for the study of control of gene expression. PMID:12072474

  19. A Malus crabapple chalcone synthase gene, McCHS, regulates red petal color and flavonoid biosynthesis.

    PubMed

    Tai, Deqiang; Tian, Ji; Zhang, Jie; Song, Tingting; Yao, Yuncong

    2014-01-01

    Chalcone synthase is a key and often rate-limiting enzyme in the biosynthesis of anthocyanin pigments that accumulate in plant organs such as flowers and fruits, but the relationship between CHS expression and the petal coloration level in different cultivars is still unclear. In this study, three typical crabapple cultivars were chosen based on different petal colors and coloration patterns. The two extreme color cultivars, 'Royalty' and 'Flame', have dark red and white petals respectively, while the intermediate cultivar 'Radiant' has pink petals. We detected the flavoniods accumulation and the expression levels of McCHS during petals expansion process in different cultivars. The results showed McCHS have their special expression patterns in each tested cultivars, and is responsible for the red coloration and color variation in crabapple petals, especially for color fade process in 'Radiant'. Furthermore, tobacco plants constitutively expressing McCHS displayed a higher anthocyanins accumulation and a deeper red petal color compared with control untransformed lines. Moreover, the expression levels of several anthocyanin biosynthetic genes were higher in the transgenic McCHS overexpressing tobacco lines than in the control plants. A close relationship was observed between the expression of McCHS and the transcription factors McMYB4 and McMYB5 during petals development in different crabapple cultivars, suggesting that the expression of McCHS was regulated by these transcription factors. We conclude that the endogenous McCHS gene is a critical factor in the regulation of anthocyanin biosynthesis during petal coloration in Malus crabapple. PMID:25357207

  20. A Malus Crabapple Chalcone Synthase Gene, McCHS, Regulates Red Petal Color and Flavonoid Biosynthesis

    PubMed Central

    Song, Tingting; Yao, Yuncong

    2014-01-01

    Chalcone synthase is a key and often rate-limiting enzyme in the biosynthesis of anthocyanin pigments that accumulate in plant organs such as flowers and fruits, but the relationship between CHS expression and the petal coloration level in different cultivars is still unclear. In this study, three typical crabapple cultivars were chosen based on different petal colors and coloration patterns. The two extreme color cultivars, ‘Royalty’ and ‘Flame’, have dark red and white petals respectively, while the intermediate cultivar ‘Radiant’ has pink petals. We detected the flavoniods accumulation and the expression levels of McCHS during petals expansion process in different cultivars. The results showed McCHS have their special expression patterns in each tested cultivars, and is responsible for the red coloration and color variation in crabapple petals, especially for color fade process in ‘Radiant’. Furthermore, tobacco plants constitutively expressing McCHS displayed a higher anthocyanins accumulation and a deeper red petal color compared with control untransformed lines. Moreover, the expression levels of several anthocyanin biosynthetic genes were higher in the transgenic McCHS overexpressing tobacco lines than in the control plants. A close relationship was observed between the expression of McCHS and the transcription factors McMYB4 and McMYB5 during petals development in different crabapple cultivars, suggesting that the expression of McCHS was regulated by these transcription factors. We conclude that the endogenous McCHS gene is a critical factor in the regulation of anthocyanin biosynthesis during petal coloration in Malus crabapple. PMID:25357207

  1. Novel insights into regulation of asparagine synthetase in conifers.

    PubMed

    Canales, Javier; Rueda-López, Marina; Craven-Bartle, Blanca; Avila, Concepción; Cánovas, Francisco M

    2012-01-01

    Asparagine, a key amino acid for nitrogen storage and transport in plants, is synthesized via the ATP-dependent reaction catalyzed by the enzyme asparagine synthetase (AS; EC 6.3.5.4). In this work, we present the molecular analysis of two full-length cDNAs that encode asparagine synthetase in maritime pine (Pinus pinaster Ait.), PpAS1, and PpAS2. Phylogenetic analyses of the deduced amino acid sequences revealed that both genes are class II AS, suggesting an ancient origin of these genes in plants. A comparative study of PpAS1 and PpAS2 gene expression profiles showed that PpAS1 gene is highly regulated by developmental and environmental factors, while PpAS2 is expressed constitutively. To determine the molecular mechanisms underpinning the differential expression of PpAS1, the promoter region of the gene was isolated and putative binding sites for MYB transcription factors were identified. Gel mobility shift assays showed that a MYB protein from Pinus taeda (PtMYB1) was able to interact with the promoter region of PpAS1. Furthermore, transient expression analyses in pine cells revealed a negative effect of PtMYB1 on PpAS1 expression. The potential role of MYB factors in the transcriptional regulation of PpAS1 in vascular cells is discussed.

  2. A Conserved Network of Transcriptional Activators and Repressors Regulates Anthocyanin Pigmentation in Eudicots[C][W][OPEN

    PubMed Central

    Albert, Nick W.; Davies, Kevin M.; Lewis, David H.; Zhang, Huaibi; Montefiori, Mirco; Brendolise, Cyril; Boase, Murray R.; Ngo, Hanh; Jameson, Paula E.; Schwinn, Kathy E.

    2014-01-01

    Plants require sophisticated regulatory mechanisms to ensure the degree of anthocyanin pigmentation is appropriate to myriad developmental and environmental signals. Central to this process are the activity of MYB-bHLH-WD repeat (MBW) complexes that regulate the transcription of anthocyanin genes. In this study, the gene regulatory network that regulates anthocyanin synthesis in petunia (Petunia hybrida) has been characterized. Genetic and molecular evidence show that the R2R3-MYB, MYB27, is an anthocyanin repressor that functions as part of the MBW complex and represses transcription through its C-terminal EAR motif. MYB27 targets both the anthocyanin pathway genes and basic-helix-loop-helix (bHLH) ANTHOCYANIN1 (AN1), itself an essential component of the MBW activation complex for pigmentation. Other features of the regulatory network identified include inhibition of AN1 activity by the competitive R3-MYB repressor MYBx and the activation of AN1, MYB27, and MYBx by the MBW activation complex, providing for both reinforcement and feedback regulation. We also demonstrate the intercellular movement of the WDR protein (AN11) and R3-repressor (MYBx), which may facilitate anthocyanin pigment pattern formation. The fundamental features of this regulatory network in the Asterid model of petunia are similar to those in the Rosid model of Arabidopsis thaliana and are thus likely to be widespread in the Eudicots. PMID:24642943

  3. Dynamics of bacterial gene regulation

    NASA Astrophysics Data System (ADS)

    Narang, Atul

    2009-03-01

    The phenomenon of diauxic growth is a classical problem of bacterial gene regulation. The most well studied example of this phenomenon is the glucose-lactose diauxie, which occurs because the expression of the lac operon is strongly repressed in the presence of glucose. This repression is often explained by appealing to molecular mechanisms such as cAMP activation and inducer exclusion. I will begin by analyzing data showing that these molecular mechanisms cannot explain the strong lac repression because they exert a relatively weak effect. I will then present a minimal model accounting only for enzyme induction and dilution, which yields strong repression despite the absence of catabolite repression and inducer exclusion. The model also explains the growth patterns observed in batch and continuous cultures of various bacterial strains and substrate mixtures. The talk will conclude with a discussion of the experimental evidence regarding positive feedback, the key component of the minimal model.

  4. The rice R2R3-MYB transcription factor OsMYB55 is involved in the tolerance to high temperature and modulates amino acid metabolism.

    PubMed

    El-Kereamy, Ashraf; Bi, Yong-Mei; Ranathunge, Kosala; Beatty, Perrin H; Good, Allen G; Rothstein, Steven J

    2012-01-01

    Temperatures higher than the optimum negatively affects plant growth and development. Tolerance to high temperature is a complex process that involves several pathways. Understanding this process, especially in crops such as rice, is essential to prepare for predicted climate changes due to global warming. Here, we show that OsMYB55 is induced by high temperature and overexpression of OsMYB55 resulted in improved plant growth under high temperature and decreased the negative effect of high temperature on grain yield. Transcriptome analysis revealed an increase in expression of several genes involved in amino acids metabolism. We demonstrate that OsMYB55 binds to the promoter regions of target genes and directly activates expression of some of those genes including glutamine synthetase (OsGS1;2) glutamine amidotransferase (GAT1) and glutamate decarboxylase 3 (GAD3). OsMYB55 overexpression resulted in an increase in total amino acid content and of the individual amino acids produced by the activation of the above mentioned genes and known for their roles in stress tolerance, namely L-glutamic acid, GABA and arginine especially under high temperature condition. In conclusion, overexpression of OsMYB55 improves rice plant tolerance to high temperature, and this high tolerance is associated with enhanced amino acid metabolism through transcription activation.

  5. Identification of a cis-regulatory element by transient analysis of co-ordinately regulated genes

    PubMed Central

    Dare, Andrew P; Schaffer, Robert J; Lin-Wang, Kui; Allan, Andrew C; Hellens, Roger P

    2008-01-01

    Background Transcription factors (TFs) co-ordinately regulate target genes that are dispersed throughout the genome. This co-ordinate regulation is achieved, in part, through the interaction of transcription factors with conserved cis-regulatory motifs that are in close proximity to the target genes. While much is known about the families of transcription factors that regulate gene expression in plants, there are few well characterised cis-regulatory motifs. In Arabidopsis, over-expression of the MYB transcription factor PAP1 (PRODUCTION OF ANTHOCYANIN PIGMENT 1) leads to transgenic plants with elevated anthocyanin levels due to the co-ordinated up-regulation of genes in the anthocyanin biosynthetic pathway. In addition to the anthocyanin biosynthetic genes, there are a number of un-associated genes that also change in expression level. This may be a direct or indirect consequence of the over-expression of PAP1. Results Oligo array analysis of PAP1 over-expression Arabidopsis plants identified genes co-ordinately up-regulated in response to the elevated expression of this transcription factor. Transient assays on the promoter regions of 33 of these up-regulated genes identified eight promoter fragments that were transactivated by PAP1. Bioinformatic analysis on these promoters revealed a common cis-regulatory motif that we showed is required for PAP1 dependent transactivation. Conclusion Co-ordinated gene regulation by individual transcription factors is a complex collection of both direct and indirect effects. Transient transactivation assays provide a rapid method to identify direct target genes from indirect target genes. Bioinformatic analysis of the promoters of these direct target genes is able to locate motifs that are common to this sub-set of promoters, which is impossible to identify with the larger set of direct and indirect target genes. While this type of analysis does not prove a direct interaction between protein and DNA, it does provide a tool to

  6. Down-regulation of CBP80 gene expression as a strategy to engineer a drought-tolerant potato.

    PubMed

    Pieczynski, Marcin; Marczewski, Waldemar; Hennig, Jacek; Dolata, Jakub; Bielewicz, Dawid; Piontek, Paulina; Wyrzykowska, Anna; Krusiewicz, Dominika; Strzelczyk-Zyta, Danuta; Konopka-Postupolska, Dorota; Krzeslowska, Magdalena; Jarmolowski, Artur; Szweykowska-Kulinska, Zofia

    2013-05-01

    Developing new strategies for crop plants to respond to drought is crucial for their innovative breeding. The down-regulation of nuclear cap-binding proteins in Arabidopsis renders plants drought tolerant. The CBP80 gene in the potato cultivar Desiree was silenced using artificial microRNAs. Transgenic plants displayed a higher tolerance to drought, ABA-hypersensitive stomatal closing, an increase in leaf stomata and trichome density, and compact cuticle structures with a lower number of microchannels. These findings were correlated with a higher tolerance to water stress. The level of miR159 was decreased, and the levels of its target mRNAs MYB33 and MYB101 increased in the transgenic plants subjected to drought. Similar trends were observed in an Arabidopsis cbp80 mutant. The evolutionary conservation of CBP80, a gene that plays a role in the response to drought, suggests that it is a candidate for genetic manipulations that aim to obtain improved water-deficit tolerance of crop plants. PMID:23231480

  7. The p53-p21-DREAM-CDE/CHR pathway regulates G2/M cell cycle genes.

    PubMed

    Fischer, Martin; Quaas, Marianne; Steiner, Lydia; Engeland, Kurt

    2016-01-01

    The tumor suppressor p53 functions predominantly as a transcription factor by activating and downregulating gene expression, leading to cell cycle arrest or apoptosis. p53 was shown to indirectly repress transcription of the CCNB2, KIF23 and PLK4 cell cycle genes through the recently discovered p53-p21-DREAM-CDE/CHR pathway. However, it remained unclear whether this pathway is commonly used. Here, we identify genes regulated by p53 through this pathway in a genome-wide computational approach. The bioinformatic analysis is based on genome-wide DREAM complex binding data, p53-depedent mRNA expression data and a genome-wide definition of phylogenetically conserved CHR promoter elements. We find 210 target genes that are expected to be regulated by the p53-p21-DREAM-CDE/CHR pathway. The target gene list was verified by detailed analysis of p53-dependent repression of the cell cycle genes B-MYB (MYBL2), BUB1, CCNA2, CCNB1, CHEK2, MELK, POLD1, RAD18 and RAD54L. Most of the 210 target genes are essential regulators of G2 phase and mitosis. Thus, downregulation of these genes through the p53-p21-DREAM-CDE/CHR pathway appears to be a principal mechanism for G2/M cell cycle arrest by p53.

  8. The p53-p21-DREAM-CDE/CHR pathway regulates G2/M cell cycle genes

    PubMed Central

    Fischer, Martin; Quaas, Marianne; Steiner, Lydia; Engeland, Kurt

    2016-01-01

    The tumor suppressor p53 functions predominantly as a transcription factor by activating and downregulating gene expression, leading to cell cycle arrest or apoptosis. p53 was shown to indirectly repress transcription of the CCNB2, KIF23 and PLK4 cell cycle genes through the recently discovered p53-p21-DREAM-CDE/CHR pathway. However, it remained unclear whether this pathway is commonly used. Here, we identify genes regulated by p53 through this pathway in a genome-wide computational approach. The bioinformatic analysis is based on genome-wide DREAM complex binding data, p53-depedent mRNA expression data and a genome-wide definition of phylogenetically conserved CHR promoter elements. We find 210 target genes that are expected to be regulated by the p53-p21-DREAM-CDE/CHR pathway. The target gene list was verified by detailed analysis of p53-dependent repression of the cell cycle genes B-MYB (MYBL2), BUB1, CCNA2, CCNB1, CHEK2, MELK, POLD1, RAD18 and RAD54L. Most of the 210 target genes are essential regulators of G2 phase and mitosis. Thus, downregulation of these genes through the p53-p21-DREAM-CDE/CHR pathway appears to be a principal mechanism for G2/M cell cycle arrest by p53. PMID:26384566

  9. Genomic and transcriptomic characterization of the transcription factor family R2R3-MYB in soybean and its involvement in the resistance responses to Phakopsora pachyrhizi.

    PubMed

    Aoyagi, Luciano N; Lopes-Caitar, Valéria S; de Carvalho, Mayra C C G; Darben, Luana M; Polizel-Podanosqui, Adriana; Kuwahara, Marcia K; Nepomuceno, Alexandre L; Abdelnoor, Ricardo V; Marcelino-Guimarães, Francismar C

    2014-12-01

    Myb genes constitute one of the largest transcription factor families in the plant kingdom. Soybean MYB transcription factors have been related to the plant response to biotic stresses. Their involvement in response to Phakopsora pachyrhizi infection has been reported by several transcriptional studies. Due to their apparently highly diverse functions, these genes are promising targets for developing crop varieties resistant to diseases. In the present study, the identification and phylogenetic analysis of the soybean R2R3-MYB (GmMYB) transcription factor family was performed and the expression profiles of these genes under biotic stress were determined. GmMYBs were identified from the soybean genome using bioinformatic tools, and their putative functions were determined based on the phylogenetic tree and classified into subfamilies using guides AtMYBs describing known functions. The transcriptional profiles of GmMYBs upon infection with different pathogen were revealed by in vivo and in silico analyses. Selected target genes potentially involved in disease responses were assessed by RT-qPCR after different times of inoculation with P. pachyrhizi using different genetic backgrounds related to resistance genes (Rpp2 and Rpp5). R2R3-MYB transcription factors related to lignin synthesis and genes responsive to chitin were significantly induced in the resistant genotypes.

  10. A validated gene regulatory network and GWAS identifies early regulators of T cell-associated diseases.

    PubMed

    Gustafsson, Mika; Gawel, Danuta R; Alfredsson, Lars; Baranzini, Sergio; Björkander, Janne; Blomgran, Robert; Hellberg, Sandra; Eklund, Daniel; Ernerudh, Jan; Kockum, Ingrid; Konstantinell, Aelita; Lahesmaa, Riita; Lentini, Antonio; Liljenström, H Robert I; Mattson, Lina; Matussek, Andreas; Mellergård, Johan; Mendez, Melissa; Olsson, Tomas; Pujana, Miguel A; Rasool, Omid; Serra-Musach, Jordi; Stenmarker, Margaretha; Tripathi, Subhash; Viitala, Miro; Wang, Hui; Zhang, Huan; Nestor, Colm E; Benson, Mikael

    2015-11-11

    Early regulators of disease may increase understanding of disease mechanisms and serve as markers for presymptomatic diagnosis and treatment. However, early regulators are difficult to identify because patients generally present after they are symptomatic. We hypothesized that early regulators of T cell-associated diseases could be found by identifying upstream transcription factors (TFs) in T cell differentiation and by prioritizing hub TFs that were enriched for disease-associated polymorphisms. A gene regulatory network (GRN) was constructed by time series profiling of the transcriptomes and methylomes of human CD4(+) T cells during in vitro differentiation into four helper T cell lineages, in combination with sequence-based TF binding predictions. The TFs GATA3, MAF, and MYB were identified as early regulators and validated by ChIP-seq (chromatin immunoprecipitation sequencing) and small interfering RNA knockdowns. Differential mRNA expression of the TFs and their targets in T cell-associated diseases supports their clinical relevance. To directly test if the TFs were altered early in disease, T cells from patients with two T cell-mediated diseases, multiple sclerosis and seasonal allergic rhinitis, were analyzed. Strikingly, the TFs were differentially expressed during asymptomatic stages of both diseases, whereas their targets showed altered expression during symptomatic stages. This analytical strategy to identify early regulators of disease by combining GRNs with genome-wide association studies may be generally applicable for functional and clinical studies of early disease development. PMID:26560356

  11. Overexpression of SbMyb60 impacts phenylpropanoid biosynthesis and alters secondary cell wall composition in sorghum bicolor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phenylpropanoid biosynthesis pathway that generates lignin subunits represents a significant target to alter the abundance and composition of lignin. The major regulators of phenylpropanoid metabolism are myb transcription factors, which have been shown to modulate secondary cell wall compositi...

  12. Coordination of seed dormancy and germination processes by MYB96.

    PubMed

    Lee, Kyounghee; Seo, Pil Joon

    2015-01-01

    The transition between seed dormancy and germination is an important stage that initiates plant life cycle. Hormonal balances of abscisic acid (ABA) and gibberellin (GA) contribute to determining the proper timing to germinate. Here, we demonstrate that the R2R3-type MYB96 transcription factor, a key ABA signaling mediator, coordinates seed dormancy and germination processes through distinct downstream events. This transcription factor controls ABA-INSENSITIVE 4 (ABI4) expression to inhibit seed germination by suppressing breakdown of lipid reserves in embryo. In addition, it also induces seed dormancy by stimulating ABA biosynthesis in an ABI4-independent manner. We propose that MYB96 integrates a multitude of environmental stress signals and acts as a master regulator in the determination of timing for seed germination.

  13. Coordination of seed dormancy and germination processes by MYB96

    PubMed Central

    Lee, Kyounghee; Seo, Pil Joon

    2015-01-01

    The transition between seed dormancy and germination is an important stage that initiates plant life cycle. Hormonal balances of abscisic acid (ABA) and gibberellin (GA) contribute to determining the proper timing to germinate. Here, we demonstrate that the R2R3-type MYB96 transcription factor, a key ABA signaling mediator, coordinates seed dormancy and germination processes through distinct downstream events. This transcription factor controls ABA-INSENSITIVE 4 (ABI4) expression to inhibit seed germination by suppressing breakdown of lipid reserves in embryo. In addition, it also induces seed dormancy by stimulating ABA biosynthesis in an ABI4-independent manner. We propose that MYB96 integrates a multitude of environmental stress signals and acts as a master regulator in the determination of timing for seed germination. PMID:26313409

  14. A Novel bHLH Transcription Factor Involved in Regulating Anthocyanin Biosynthesis in Chrysanthemums (Chrysanthemum morifolium Ramat.).

    PubMed

    Xiang, Li-li; Liu, Xiao-fen; Li, Xue; Yin, Xue-ren; Grierson, Donald; Li, Fang; Chen, Kun-song

    2015-01-01

    Chrysanthemums (Chrysanthemum morifolium Ramat.) exhibit a variety of flower colors due to their differing abilities to accumulate anthocyanins. One MYB member, CmMYB6, has been verified as a transcription regulator of chrysanthemum genes involved in anthocyanin biosynthesis; however, the co-regulators for CmMYB6 remain unclear in chrysanthemum. Here, the expression pattern of CmbHLH2, which is clustered in the IIIf bHLH subgroup, was shown to be positively correlated with the anthocyanin content of cultivars with red, pink and yellow flower colors, respectively. CmbHLH2 significantly upregulated the CmDFR promoter and triggered anthocyanin accumulation when co-expressed with CmMYB6. Yeast one-hybrid analyses indicated that CmbHLH2 was able to bind directly to the CmDFR promoter. Moreover, yeast two-hybrid assays indicated protein-protein interaction between CmbHLH2 and CmMYB6. These results suggest that CmbHLH2 is the essential partner for CmMYB6 in regulating anthocyanin biosynthesis in chrysanthemum. PMID:26619181

  15. A Novel bHLH Transcription Factor Involved in Regulating Anthocyanin Biosynthesis in Chrysanthemums (Chrysanthemum morifolium Ramat.)

    PubMed Central

    Li, Xue; Yin, Xue-ren; Grierson, Donald; Li, Fang; Chen, Kun-song

    2015-01-01

    Chrysanthemums (Chrysanthemum morifolium Ramat.) exhibit a variety of flower colors due to their differing abilities to accumulate anthocyanins. One MYB member, CmMYB6, has been verified as a transcription regulator of chrysanthemum genes involved in anthocyanin biosynthesis; however, the co-regulators for CmMYB6 remain unclear in chrysanthemum. Here, the expression pattern of CmbHLH2, which is clustered in the IIIf bHLH subgroup, was shown to be positively correlated with the anthocyanin content of cultivars with red, pink and yellow flower colors, respectively. CmbHLH2 significantly upregulated the CmDFR promoter and triggered anthocyanin accumulation when co-expressed with CmMYB6. Yeast one-hybrid analyses indicated that CmbHLH2 was able to bind directly to the CmDFR promoter. Moreover, yeast two-hybrid assays indicated protein-protein interaction between CmbHLH2 and CmMYB6. These results suggest that CmbHLH2 is the essential partner for CmMYB6 in regulating anthocyanin biosynthesis in chrysanthemum. PMID:26619181

  16. Regulation of Neuronal Gene Expression

    NASA Astrophysics Data System (ADS)

    Thiel, Gerald; Lietz, Michael; Leichter, Michael

    Humans as multicellular organisms contain a variety of different cell types where each cell population must fulfill a distinct function in the interest of the whole organism. The molecular basis for the variations in morphology, biochemistry, molecular biology, and function of the various cell types is the cell-type specific expression of genes. These genes encode proteins necessary for executing the specialized functions of each cell type within an organism. We describe here a regulatory mechanism for the expression of neuronal genes. The zinc finger protein REST binds to the regulatory region of many neuronal genes and represses neuronal gene expression in nonneuronal tissues. A negative regulatory mechanism, involving a transcriptional repressor, seems to play an important role in establishing the neuronal phenotype.

  17. A R2R3-MYB transcription factor from Lablab purpureus induced by drought increases tolerance to abiotic stress in Arabidopsis.

    PubMed

    Yao, Luming; Jiang, Yina; Lu, Xinxin; Wang, Biao; Zhou, Pei; Wu, Tianlong

    2016-10-01

    Few regulators for drought tolerance have been identified in Lablab purpureus which is a multipurpose leguminous crop. The transcription factor MYB is involved in regulatory networks in response to abiotic and biotic stresses in plants. A novel R2R3-MYB factor in L. purpureus has been identified. An suppression subtraction hybridization (SSH) library was constructed using root tissues of L. purpureus MEIDOU 2012 from well-watered and water-stress treatments that were subjected to drought stress for 10 days. In addition, the cDNA of LpMYB1 was identified based on the SSH library. The cDNA of LpMYB1 is 858 bp and encodes a 285-amino acid protein with a calculated mass of 33.4 kDa. The LpMYB1 protein localizes to the nucleus and has transactivation activity with the activation domain in the C terminal region of the protein. In LpMYB1 overexpressed Arabidopsis, the tolerance of transgenic seedlings to drought and salt was improved, and the germination potential of transgenic seeds increase in the presence of NaCl or ABA. LpMYB1 is a drought-responsive R2R3-MYB factor that can increase the drought and salt tolerance of LpMYB1-overexpressed Arabidopsis. PMID:27565983

  18. Preferential up-regulation of G2/M phase-specific genes by overexpression of the hyperactive form of NtmybA2 lacking its negative regulation domain in tobacco BY-2 cells.

    PubMed

    Kato, Kiichi; Gális, Ivan; Suzuki, Shiori; Araki, Satoshi; Demura, Taku; Criqui, Marie-Claire; Potuschak, Thomas; Genschik, Pascal; Fukuda, Hiroo; Matsuoka, Ken; Ito, Masaki

    2009-04-01

    Many G2/M phase-specific genes in plants contain mitosis-specific activator (MSA) elements, which act as G2/M phase-specific enhancers and bind with R1R2R3-Myb transcription factors. Here, we examined the genome-wide effects of NtmybA2 overexpression, one of the R1R2R3-Myb transcription factors in tobacco (Nicotiana tabacum). We used a custom-made 16-K cDNA microarray for comparative transcriptome analysis of transgenic tobacco BY-2 cell lines that overexpress NtmybA2 or its truncated hyperactive form. The microarray was also used to determine the transcript profile during the cell cycle in synchronized cultures of BY-2 cells. Combined microarray data from transgenic lines and synchronized cells revealed that overexpression of the truncated hyperactive form of NtmybA2, but not its full-length form, preferentially up-regulated many G2/M phase-specific genes in BY-2 cells. We determined promoter sequences of several such up-regulated genes and showed that all contain MSA-like motifs in the proximal regions of their promoters. One of the up-regulated genes, NtE2C, encoding for cyclin-specific ubiquitin carrier proteins, contained a single functional MSA-like motif, which specifically controlled the expression of a reporter gene in the G2/M phase in BY-2 cells. Furthermore, a genomic footprint experiment showed that the MSA element in the NtE2C promoter interacted with nuclear proteins in vivo. Therefore, we propose that the transcription of many G2/M phase-specific genes in tobacco is positively regulated by NtmybA2, in most cases through direct binding to the MSA elements. PMID:19244455

  19. Gene Regulation Networks for Modeling Drosophila Development

    NASA Technical Reports Server (NTRS)

    Mjolsness, E.

    1999-01-01

    This chapter will very briefly introduce and review some computational experiments in using trainable gene regulation network models to simulate and understand selected episodes in the development of the fruit fly, Drosophila Melanogaster.

  20. Endogenous and ectopic expression of telomere regulating genes in chicken embryonic fibroblasts

    SciTech Connect

    Michailidis, Georgios; Saretzki, Gabriele; Hall, Judith , E-Mail: Judith.hall@ncl.ac.uk

    2005-09-16

    In this study, we compared the endogenous expression of genes encoding telomere regulating proteins in cultured chicken embryonic fibroblasts (CEFs) and 10-day-old chicken embryos. CEFs maintained in vitro senesced and senescence was accompanied by reduced telomere length, telomerase activity, and expression of the chicken (c) TRF1 gene. There was no change in TRF2 gene expression although the major TRF2 transcript identified in 10-day-old chicken embryos encoded a truncated TRF2 protein (TRF2'), containing an N-terminal dimerisation domain but lacking a myb-related DNA binding domain and nuclear localisation signal. Senescence of the CEFs in vitro was associated with the loss of the TRF2' transcript, indicative of a novel function for the encoded protein. Senescence was also coupled with decreased expression of RAD51, but increased RAD52 expression. These data support that RAD51 independent recombination mechanisms do not function in vitro to maintain chicken telomeres. To attempt to rescue the CEFs from replicative senescence, we stably transfected passage 3 CEFs with the human telomerase reverse transcriptase (hTERT) catalytic subunit. While hTERT expression was detected in the stable transfectants neither telomerase activity nor the stabilisation of telomere length was observed, and the transfectant cells senesced at the same passage number as the untransfected cells. These data indicate that the human TERT is incompatible with the avian telomere maintenance apparatus and suggest the functioning of a species specific telomere system in the avian.

  1. Cytoskeletal genes regulating brain size.

    PubMed

    Bond, Jacquelyn; Woods, C Geoffrey

    2006-02-01

    One of the most notable trends in human evolution is the dramatic increase in brain size that has occurred in the great ape clade, culminating in humans. Of particular interest is the vast expanse of the cerebral cortex, which is believed to have resulted in our ability to perform higher cognitive functions. Recent investigations of congenital microcephaly in humans have resulted in the identification of several genes that non-redundantly and specifically influence mammalian brain size. These genes appear to affect neural progenitor cell number through microtubular organisation at the centrosome. PMID:16337370

  2. How Europe regulates its genes

    SciTech Connect

    Balter, M.

    1991-06-07

    As Europe moves toward unification in 1992, more than two dozen regulations and directives that will affect biotech are working their way through the complex European legislative system. The result could mean tough scrutiny for genetically engineered products. One reason is that the European Community (EC) has chosen to examine genetically engineered products as a special category - an approach the FDA has rejected. Another is that the EC is considering enacting regulations that would mandate consideration of the socioeconomic effects of biotech products in addition to their safety. In addition, some - particularly in industry - fear a nightmare of overlapping and contradictory regulations. It's too soon to tell how well the European system will work, or how stifling the regulations might be. In all likelihood the regulations emerging in Europe won't be demonstrably superior - or inferior - to the American ones, just different, with different strengths and weaknesses. But since many US biotech companies are looking to the huge market that a unified Europe represents, the specifics of those strengths and weaknesses will ultimately be of more than passing interest.

  3. The transcriptional response of apple alcohol acyltransferase (MdAAT2) to salicylic acid and ethylene is mediated through two apple MYB TFs in transgenic tobacco.

    PubMed

    Li, Peng-Cheng; Yu, Shao-Wei; Shen, Jin; Li, Qing-Qing; Li, Da-Peng; Li, De-Quan; Zheng, Cheng-Chao; Shu, Huai-Rui

    2014-08-01

    Volatile esters are major factors affecting the aroma of apple fruits, and alcohol acyltransferases (AATs) are key enzymes involved in the last steps of ester biosynthesis. The expression of apple AAT (MdAAT2) is known to be induced by salicylic acid (SA) or ethylene in apple fruits, although the mechanism of its transcriptional regulation remains elusive. In this study, we reveal that two apple transcription factors (TFs), MdMYB1 and MdMYB6, are involved in MdAAT2 promoter response to SA and ethylene in transgenic tobacco. According to electrophoretic mobility shift assays, MdMYB1 or MdMYB6 can directly bind in vitro to MYB binding sites in the MdAAT2 promoter. In vivo, overexpression of the two MYB TFs can greatly enhance MdAAT2 promoter activity, as demonstrated by dual luciferase reporter assays in transgenic tobacco. In contrast to the promoter of MdMYB1 or MdMYB6, the MdAAT2 promoter cannot be induced by SA or ethephon (ETH) in transgenic tobacco, even in stigmas in which the MdAAT2 promoter can be highly induced under normal conditions. However, the induced MYB TFs can dramatically enhance MdAAT2 promoter activity under SA or ETH treatment. We conclude that MdMYB1 and MdMYB6 function in MdAAT2 responses to SA and ethylene in transgenic tobacco, suggesting that a similar regulation mechanism may exist in apple.

  4. Regulation of Flagellar Gene Expression in Bacteria.

    PubMed

    Osterman, I A; Dikhtyar, Yu Yu; Bogdanov, A A; Dontsova, O A; Sergiev, P V

    2015-11-01

    The flagellum of a bacterium is a supramolecular structure of extreme complexity comprising simultaneously both a unique system of protein transport and a molecular machine that enables the bacterial cell movement. The cascade of expression of genes encoding flagellar components is closely coordinated with the steps of molecular machine assembly, constituting an amazing regulatory system. Data on structure, assembly, and regulation of flagellar gene expression are summarized in this review. The regulatory mechanisms and correlation of the process of regulation of gene expression and flagellum assembly known from the literature are described. PMID:26615435

  5. Detection of MYB Alterations and Other Immunohistochemical Markers in Primary Cutaneous Adenoid Cystic Carcinoma.

    PubMed

    North, Jeffrey P; McCalmont, Timothy H; Fehr, André; van Zante, Annemieke; Stenman, Göran; LeBoit, Philip E

    2015-10-01

    Adenoid cystic carcinoma (ACC) can arise in several organs, and prognosis is highly dependent on the primary tumor site. Primary cutaneous ACC has an excellent prognosis compared with salivary or lacrimal ACC. Activation of MYB by gene fusion or other mechanisms has been found in salivary, breast, and lacrimal ACCs but has not been described in cutaneous ACC. We analyzed the histopathologic and immunohistochemical features of 19 primary cutaneous ACCs, 2 periorbital ACCs, and 12 salivary gland ACCs and assessed for MYB activation in primary cutaneous ACC by immunohistochemistry and molecular methods. The presence of perineural invasion differed significantly among ACCs of various sites (83% salivary, 50% eyelid, 11% skin, P=0.0002). Over 90% of all ACCs were grade 1 or 2 and exhibited diffuse (>50%) positivity with CD117, SOX-10, and smooth muscle actin immunostains. CK15 and vimentin showed diffuse positivity in 36% and 57% of cutaneous ACCs, respectively, and were negative or only focally positive in all salivary ACCs (P=0.04 and 0.002). Six of the 11 cutaneous and periorbital ACCs tested with reverse transcriptase polymerase chain reaction and/or fluorescence in situ hybridization had MYB rearrangements including 2 cases that expressed MYB-NFIB fusion transcripts. Diffuse expression of MYB protein assessed by immunostaining was present in 8 of 9 cutaneous ACCs, including cases both with and without MYB rearrangements. These results indicate that cutaneous ACCs possess the same types of MYB alterations as ACCs of other anatomic sites. Vimentin and CK15 appear to have some discriminatory value in differentiating between primary cutaneous and salivary gland ACCs. PMID:26076064

  6. [Expression and regulation of the SOST gene].

    PubMed

    Qin, Long-Juan; Ding, Da-Xia; Cui, Lu-Lu; Huang, Qing-Yang

    2013-08-01

    Sclerostin(SOST), mainly expressed in osteocytes, is a negative regulator of bone formation. Hormones PTH and E2 inhibit the expression of the SOST gene. Transcription factors Osterix, Runx2, and Mef2c promote the SOST expression, while Sirt1 negatively regulates the SOST expression. In addition, the expression of the SOST gene is regulated by epigenetic mechanisms, such as DNA methylation and microRNA. Mutations in the SOST gene, which cause sclerosteosis and Van Buchem diseases, are associated with osteoporosis. Wnt and BMP are two important signaling pathways in bone metabolic regulation. SOST can regulate osteoblastic differentiation and bone formation by binding type I/II receptors and co-receptor LRP5/6 to inhibit BMP and Wnt signaling pathways. Suppression of SOST provides a new approach for osteoporosis treatment. This review covers the structure, function and expression regulation of the SOST gene, human disease association, mechanism in the regulation of bone metabolism and prospect in clinical application.

  7. Genome-wide identification and characterization of R2R3MYB family in Rosaceae.

    PubMed

    González, Máximo; Carrasco, Basilio; Salazar, Erika

    2016-09-01

    Transcription factors R2R3MYB family have been associated with the control of secondary metabolites, development of structures, cold tolerance and response to biotic and abiotic stress, among others. In recent years, genomes of Rosaceae botanical family are available. Although this information has been used to study the karyotype evolution of these species from an ancestral genome, there are no studies that treat the evolution and diversity of gene families present in these species or in the botanical family. Here we present the first comparative study of the R2R3MYB subfamily of transcription factors in three species of Rosaceae family (Malus domestica, Prunus persica and Fragaria vesca). We described 186, 98 and 86 non-redundant gene models for apple, peach and strawberry, respectively. In this research, we analyzed the intron-exon structure and genomic distribution of R2R3MYB families mentioned above. The phylogenetic comparisons revealed putative functions of some R2R3MYB transcription factors. This analysis found 44 functional subgroups, seven of which were unique for Rosaceae. In addition, our results showed a highly collinearity among some genes revealing the existence of conserved gene models between the three species studied. Although some gene models in these species have been validated under several approaches, more research in the Rosaceae family is necessary to determine gene expression patterns in specific tissues and development stages to facilitate understanding of the regulatory and biochemical mechanism in this botanical family. PMID:27408811

  8. Seasonal abscisic acid signal and a basic leucine zipper transcription factor, DkbZIP5, regulate proanthocyanidin biosynthesis in persimmon fruit.

    PubMed

    Akagi, Takashi; Katayama-Ikegami, Ayako; Kobayashi, Shozo; Sato, Akihiko; Kono, Atsushi; Yonemori, Keizo

    2012-02-01

    Proanthocyanidins (PAs) are secondary metabolites that contribute to plant protection and crop quality. Persimmon (Diospyros kaki) has a unique characteristic of accumulating large amounts of PAs, particularly in its fruit. Normal astringent-type and mutant nonastringent-type fruits show different PA accumulation patterns depending on the seasonal expression patterns of DkMyb4, which is a Myb transcription factor (TF) regulating many PA pathway genes in persimmon. In this study, attempts were made to identify the factors involved in DkMyb4 expression and the resultant PA accumulation in persimmon fruit. Treatment with abscisic acid (ABA) and an ABA biosynthesis inhibitor resulted in differential changes in the expression patterns of DkMyb4 and PA biosynthesis in astringent-type and nonastringent-type fruits depending on the development stage. To obtain an ABA-signaling TF, we isolated a full-length basic leucine zipper (bZIP) TF, DkbZIP5, which is highly expressed in persimmon fruit. We also showed that ectopic DkbZIP5 overexpression in persimmon calluses induced the up-regulation of DkMyb4 and the resultant PA biosynthesis. In addition, a detailed molecular characterization using the electrophoretic mobility shift assay and transient reporter assay indicated that DkbZIP5 recognized ABA-responsive elements in the promoter region of DkMyb4 and acted as a direct regulator of DkMyb4 in an ABA-dependent manner. These results suggest that ABA signals may be involved in PA biosynthesis in persimmon fruit via DkMyb4 activation by DkbZIP5.

  9. Physiological changes in fruit ripening caused by overexpression of tomato SlAN2, an R2R3-MYB factor.

    PubMed

    Meng, Xia; Yang, Dongyue; Li, Xiaodong; Zhao, Shuya; Sui, Na; Meng, Qingwei

    2015-04-01

    The R2R3-MYB protein SlAN2 has long been thought to be a positive regulator of anthocyanin accumulation. To investigate the role of SlAN2, we have previously overexpressed the gene in tomato. In this work, we analysed physiological characters of the transgenic plants during the fruit ripening. We show that fruits of transformants overexpressing SlAN2 displayed an orange colour, fast softening and elevated ethylene production. Overexpression of SlAN2 resulted in reduction of carotenoid levels via alteration of flux through the carotenoid pathway, elevated ethylene synthesis mainly via upregulation of ethylene biosynthesis genes, and early softening of fruits. We also found that the transcript level of SlRIN, an important ripening-related gene, was up-regulated in transgenic fruits. These results suggest that SlAN2 acts as an important regulator of fruit ripening.

  10. Molecular analysis of protein domain function encoded by the myb-homologous maize genes C1, Zm 1 and Zm 38.

    PubMed

    Franken, P; Schrell, S; Peterson, P A; Saedler, H; Wienand, U

    1994-07-01

    Two maize genes, Zm 1 and Zm 38, related to the regulatory anthocyanin gene C1 were analyzed molecularly and used for fusion constructs in transient domain swapping experiments with the C1 wild-type gene. It was shown that both genes (Zm 1 and Zm 38) influence the expression of the A1 locus, a target gene for C1. Zm 1 activates the A1 promoter, however it does not turn on the whole anthocyanin pathway. The Zm 38 gene product shows functions similar to C1-I, a dominant inhibitor of the C1 wild-type gene. Concerning the trans-inhibition by C1-I two effects seem to be involved, competition for binding and formation of heterodimers. Further analysis of C1 function was carried out by a fine structure analysis of C1 mutants induced by the insertion and excision of transposable elements. These experiments indicate that for the activating domain of the protein, the formation of an alpha helix seems to be more important than a high negative charge.

  11. The paralogous R3 MYB proteins CAPRICE, TRIPTYCHON and ENHANCER OF TRY AND CPC1 play pleiotropic and partly non-redundant roles in the phosphate starvation response of Arabidopsis roots

    PubMed Central

    Chen, Chun-Ying; Schmidt, Wolfgang

    2015-01-01

    Phosphate (Pi) deficiency alters root hair length and frequency as a means of increasing the absorptive surface area of roots. Three partly redundant single R3 MYB proteins, CAPRICE (CPC), ENHANCER OF TRY AND CPC1 (ETC1) and TRIPTYCHON (TRY), positively regulate the root hair cell fate by participating in a lateral inhibition mechanism. To identify putative targets and processes that are controlled by these three transcription factors (TFs), we conducted transcriptional profiling of roots from Arabidopsis thaliana wild-type plants, and cpc, etc1 and try mutants grown under Pi-replete and Pi-deficient conditions using RNA-seq. The data show that in an intricate interplay between the three MYBs regulate several developmental, physiological and metabolic processes that are putatively located in different tissues. When grown on media with a low Pi concentration, all three TFs acquire additional functions that are related to the Pi starvation response, including transition metal transport, membrane lipid remodelling, and the acquisition, uptake and storage of Pi. Control of gene activity is partly mediated through the regulation of potential antisense transcripts. The current dataset extends the known functions of R3 MYB proteins, provides a suite of novel candidates with critical function in root hair development under both control and Pi-deficient conditions, and challenges the definition of genetic redundancy by demonstrating that environmental perturbations may confer specific functions to orthologous proteins that could have similar roles under control conditions. PMID:26022254

  12. Developmental regulation of embryonic genes in plants

    SciTech Connect

    Borkird, C.; Choi, Jung, H.; Jin, Zhenghua; Franz, G.; Hatzopoulos, P.; Chorneaus, R.; Bonas, U.; Pelegri, F.; Sung, Z.R.

    1988-09-01

    Somatic embryogenesis from cultured carrot cells progresses through successive morphogenetic stages termed globular, heart, and torpedo. To understand the molecular mechanisms underlying plant embryogenesis, the authors isolated two genes differentially expressed during embryo development. The expression of these two genes is associated with heart-stage embryogenesis. By altering the culture conditions and examining their expressions in a developmental variant cell line, they found that these genes were controlled by the developmental program of embryogenesis and were not directly regulated by 2,4-dichlorophenoxyacetic acid, the growth regulator that promotes unorganized growth of cultured cells and suppresses embryo morphogenesis. These genes are also expressed in carrot zygotic embryos but not in seedlings or mature plants.

  13. The Evolutionary History of R2R3-MYB Proteins Across 50 Eukaryotes: New Insights Into Subfamily Classification and Expansion

    PubMed Central

    Du, Hai; Liang, Zhe; Zhao, Sen; Nan, Ming-Ge; Phan Tran, Lam-Son; Lu, Kun; Huang, Yu-Bi; Li, Jia-Na

    2015-01-01

    R2R3-MYB proteins (2R-MYBs) are one of the main transcription factor families in higher plants. Since the evolutionary history of this gene family across the eukaryotic kingdom remains unknown, we performed a comparative analysis of 2R-MYBs from 50 major eukaryotic lineages, with particular emphasis on land plants. A total of 1548 candidates were identified among diverse taxonomic groups, which allowed for an updated classification of 73 highly conserved subfamilies, including many newly identified subfamilies. Our results revealed that the protein architectures, intron patterns, and sequence characteristics were remarkably conserved in each subfamily. At least four subfamilies were derived from early land plants, 10 evolved from spermatophytes, and 19 from angiosperms, demonstrating the diversity and preferential expansion of this gene family in land plants. Moreover, we determined that their remarkable expansion was mainly attributed to whole genome and segmental duplication, where duplicates were preferentially retained within certain subfamilies that shared three homologous intron patterns (a, b, and c) even though up to 12 types of patterns existed. Through our integrated distributions, sequence characteristics, and phylogenetic tree analyses, we confirm that 2R-MYBs are old and postulate that 3R-MYBs may be evolutionarily derived from 2R-MYBs via intragenic domain duplication. PMID:26047035

  14. The Evolutionary History of R2R3-MYB Proteins Across 50 Eukaryotes: New Insights Into Subfamily Classification and Expansion.

    PubMed

    Du, Hai; Liang, Zhe; Zhao, Sen; Nan, Ming-Ge; Tran, Lam-Son Phan; Lu, Kun; Huang, Yu-Bi; Li, Jia-Na

    2015-06-05

    R2R3-MYB proteins (2R-MYBs) are one of the main transcription factor families in higher plants. Since the evolutionary history of this gene family across the eukaryotic kingdom remains unknown, we performed a comparative analysis of 2R-MYBs from 50 major eukaryotic lineages, with particular emphasis on land plants. A total of 1548 candidates were identified among diverse taxonomic groups, which allowed for an updated classification of 73 highly conserved subfamilies, including many newly identified subfamilies. Our results revealed that the protein architectures, intron patterns, and sequence characteristics were remarkably conserved in each subfamily. At least four subfamilies were derived from early land plants, 10 evolved from spermatophytes, and 19 from angiosperms, demonstrating the diversity and preferential expansion of this gene family in land plants. Moreover, we determined that their remarkable expansion was mainly attributed to whole genome and segmental duplication, where duplicates were preferentially retained within certain subfamilies that shared three homologous intron patterns (a, b, and c) even though up to 12 types of patterns existed. Through our integrated distributions, sequence characteristics, and phylogenetic tree analyses, we confirm that 2R-MYBs are old and postulate that 3R-MYBs may be evolutionarily derived from 2R-MYBs via intragenic domain duplication.

  15. The HDAC inhibitor Givinostat modulates the hematopoietic transcription factors NFE2 and C-MYB in JAK2(V617F) myeloproliferative neoplasm cells.

    PubMed

    Amaru Calzada, Ariel; Todoerti, Katia; Donadoni, Luca; Pellicioli, Anna; Tuana, Giacomo; Gatta, Raffaella; Neri, Antonino; Finazzi, Guido; Mantovani, Roberto; Rambaldi, Alessandro; Introna, Martino; Lombardi, Luigia; Golay, Josée

    2012-08-01

    We investigated the mechanism of action of the histone deacetylase inhibitor Givinostat (GVS) in Janus kinase 2 (JAK2)(V617F) myeloproliferative neoplasm (MPN) cells. GVS inhibited colony formation and proliferation and induced apoptosis at doses two- to threefold lower in a panel of JAK2(V617F) MPN compared to JAK2 wild-type myeloid leukemia cell lines. By global gene expression analysis, we observed that at 6 hours, GVS modulated 293 common genes in the JAK2(V617F) cell lines HEL and UKE1, of which 19 are implicated in cell cycle regulation and 33 in hematopoiesis. In particular, the hematopoietic transcription factors NFE2 and C-MYB were downmodulated by the drug specifically in JAK2(V617F) cells at both the RNA and protein level. GVS also inhibited JAK2-signal transducer and activator of transcription 5-extracellular signal-regulated kinase 1/2 phosphorylation, but modulation of NFE2 and C-MYB was JAK2-independent, as shown using the JAK2 inhibitor TG101209. GVS had a direct effect on the NFE2 promoters, as demonstrated by specific enrichment of associated histone H3 acetylated at lysine 9. Modulation by GVS of NFE2 was also observed in freshly isolated CD34(+) cells from MPN patients, and was accompanied by inhibition of their proliferation and differentiation toward the erythroid lineage. We conclude that GVS acts on MPN cells through dual JAK2-signal transducer and activator of transcription 5-extracellular signal-regulated kinase 1/2 inhibition and downmodulation of NFE2 and C-MYB transcription. PMID:22579713

  16. GmWRKY27 interacts with GmMYB174 to reduce expression of GmNAC29 for stress tolerance in soybean plants.

    PubMed

    Wang, Fang; Chen, Hao-Wei; Li, Qing-Tian; Wei, Wei; Li, Wei; Zhang, Wan-Ke; Ma, Biao; Bi, Ying-Dong; Lai, Yong-Cai; Liu, Xin-Lei; Man, Wei-Qun; Zhang, Jin-Song; Chen, Shou-Yi

    2015-07-01

    Soybean (Glycine max) is an important crop for oil and protein resources worldwide. The molecular mechanism of the abiotic stress response in soybean is largely unclear. We previously identified multiple stress-responsive WRKY genes from soybean. Here, we further characterized the roles of one of these genes, GmWRKY27, in abiotic stress tolerance using a transgenic hairy root assay. GmWRKY27 expression was increased by various abiotic stresses. Over-expression and RNAi analysis demonstrated that GmWRKY27 improves salt and drought tolerance in transgenic soybean hairy roots. Measurement of physiological parameters, including reactive oxygen species and proline contents, supported this conclusion. GmWRKY27 inhibits expression of a downstream gene GmNAC29 by binding to the W-boxes in its promoter region. The GmNAC29 is a negative factor of stress tolerance as indicated by the performance of transgenic hairy roots under stress. GmWRKY27 interacts with GmMYB174, which also suppresses GmNAC29 expression and enhances drought stress tolerance. The GmWRKY27 and GmMYB174 may have evolved to bind to neighbouring cis elements in the GmNAC29 promoter to co-reduce promoter activity and gene expression. Our study discloses a valuable mechanism in soybean for regulation of the stress response by two associated transcription factors. Manipulation of these genes should facilitate improvements in stress tolerance in soybean and other crops.

  17. Transcriptional Profiles of Hybrid Eucalyptus Genotypes with Contrasting Lignin Content Reveal That Monolignol Biosynthesis-related Genes Regulate Wood Composition.

    PubMed

    Shinya, Tomotaka; Iwata, Eiji; Nakahama, Katsuhiko; Fukuda, Yujiroh; Hayashi, Kazunori; Nanto, Kazuya; Rosa, Antonio C; Kawaoka, Akiyoshi

    2016-01-01

    Eucalyptus species constitutes the most widely planted hardwood trees in temperate and subtropical regions. In this study, we compared the transcript levels of genes involved in lignocellulose formation such as cellulose, hemicellulose and lignin biosynthesis in two selected 3-year old hybrid Eucalyptus (Eucalyptus urophylla × Eucalyptus grandis) genotypes (AM063 and AM380) that have different lignin content. AM063 and AM380 had 20.2 and 35.5% of Klason lignin content and 59.0 and 48.2%, α-cellulose contents, respectively. We investigated the correlation between wood properties and transcript levels of wood formation-related genes using RNA-seq with total RNAs extracted from developing xylem tissues at a breast height. Transcript levels of cell wall construction genes such as cellulose synthase (CesA) and sucrose synthase (SUSY) were almost the same in both genotypes. However, AM063 exhibited higher transcript levels of UDP-glucose pyrophosphorylase and xyloglucan endotransglucoxylase than those in AM380. Most monolignol biosynthesis-related isozyme genes showed higher transcript levels in AM380. These results indicate monolignol biosynthesis-related genes may regulate wood composition in Eucalyptus. Flavonoids contents were also observed at much higher levels in AM380 as a result of the elevated transcript levels of common phenylpropanoid pathway genes, phenylalanine ammonium lyase, cinnamate-4-hydroxylase (C4H) and 4-coumarate-CoA ligase (4CL). Secondary plant cell wall formation is regulated by many transcription factors. We analyzed genes encoding NAC, WRKY, AP2/ERF, and KNOX transcription factors and found higher transcript levels of these genes in AM380. We also observed increased transcription of some MYB and LIM domain transcription factors in AM380 compared to AM063. All these results show that genes related to monolignol biosynthesis may regulate the wood composition and help maintain the ratio of cellulose and lignin contents in Eucalyptus plants. PMID

  18. Transcriptional Profiles of Hybrid Eucalyptus Genotypes with Contrasting Lignin Content Reveal That Monolignol Biosynthesis-related Genes Regulate Wood Composition

    PubMed Central

    Shinya, Tomotaka; Iwata, Eiji; Nakahama, Katsuhiko; Fukuda, Yujiroh; Hayashi, Kazunori; Nanto, Kazuya; Rosa, Antonio C.; Kawaoka, Akiyoshi

    2016-01-01

    Eucalyptus species constitutes the most widely planted hardwood trees in temperate and subtropical regions. In this study, we compared the transcript levels of genes involved in lignocellulose formation such as cellulose, hemicellulose and lignin biosynthesis in two selected 3-year old hybrid Eucalyptus (Eucalyptus urophylla × Eucalyptus grandis) genotypes (AM063 and AM380) that have different lignin content. AM063 and AM380 had 20.2 and 35.5% of Klason lignin content and 59.0 and 48.2%, α-cellulose contents, respectively. We investigated the correlation between wood properties and transcript levels of wood formation-related genes using RNA-seq with total RNAs extracted from developing xylem tissues at a breast height. Transcript levels of cell wall construction genes such as cellulose synthase (CesA) and sucrose synthase (SUSY) were almost the same in both genotypes. However, AM063 exhibited higher transcript levels of UDP-glucose pyrophosphorylase and xyloglucan endotransglucoxylase than those in AM380. Most monolignol biosynthesis-related isozyme genes showed higher transcript levels in AM380. These results indicate monolignol biosynthesis-related genes may regulate wood composition in Eucalyptus. Flavonoids contents were also observed at much higher levels in AM380 as a result of the elevated transcript levels of common phenylpropanoid pathway genes, phenylalanine ammonium lyase, cinnamate-4-hydroxylase (C4H) and 4-coumarate-CoA ligase (4CL). Secondary plant cell wall formation is regulated by many transcription factors. We analyzed genes encoding NAC, WRKY, AP2/ERF, and KNOX transcription factors and found higher transcript levels of these genes in AM380. We also observed increased transcription of some MYB and LIM domain transcription factors in AM380 compared to AM063. All these results show that genes related to monolignol biosynthesis may regulate the wood composition and help maintain the ratio of cellulose and lignin contents in Eucalyptus plants. PMID

  19. Gene regulation by dietary microRNAs.

    PubMed

    Zempleni, Janos; Baier, Scott R; Howard, Katherine M; Cui, Juan

    2015-12-01

    MicroRNAs (miRNAs) silence genes through destabilizing mRNA or preventing translation of mRNA, thereby playing an essential role in gene silencing. Traditionally, miRNAs have been considered endogenous regulators of genes, i.e., miRNAs synthesized by an organism regulate the genes in that organism. Recently, that dogma has been challenged in studies suggesting that food-borne miRNAs are bioavailable and affect gene expression in mice and humans. While the evidence in support of this theory may be considered weak for miRNAs that originate in plants, there is compelling evidence to suggest that humans use bovine miRNAs in cow's milk and avian miRNAs in chicken eggs for gene regulation. Importantly, evidence also suggests that mice fed a miRNA-depleted diet cannot compensate for dietary depletion by increased endogenous synthesis. Bioinformatics predictions implicate bovine miRNAs in the regulation of genes that play roles in human health and development. Current challenges in this area of research include that some miRNAs are unable to establish a cause-and-effect between miRNA depletion and disease in miRNA knockout mice, and sequence similarities and identities for bovine and human miRNAs render it difficult to distinguish between exogenous and endogenous miRNAs. Based on what is currently known about dietary miRNAs, the body of evidence appears to be sufficient to consider milk miRNA bioactive compounds in foods, and to increase research activities in this field.

  20. The red sport of 'Zaosu' pear and its red-striped pigmentation pattern are associated with demethylation of the PyMYB10 promoter.

    PubMed

    Qian, Minjie; Sun, Yongwang; Allan, Andrew C; Teng, Yuanwen; Zhang, Dong

    2014-11-01

    'Zaosu' pear, a hybrid of Pyrus pyrifolia and Pyrus communis, is a popular cultivar developed in China. 'Zaosu Red' is a bud sport of 'Zaosu' with red shoots, young leaves, and fruit. After grafting of 'Zaosu Red', reverse mutations in some branches lead to a loss of colour in leaves and stems. Also, the mature fruit of 'Zaosu Red' exhibits two phenotypes; fully red and striped. The aim of this study was to establish the mechanism of the red colour mutation in 'Zaosu' and the striped pigmentation pattern in fruit of 'Zaosu Red'. The accumulation of anthocyanins and transcript levels of the genes PpUFGT2 and PyMYB10 were highly correlated. The open reading frames (ORF) and promoter regions of these two key genes were cloned and compared between 'Zaosu' and its bud sports, but no sequence differences were found. The R2R3 MYB, PyMYB10, can activate expression of genes encoding enzymes of the anthocyanin biosynthetic pathway. A yeast one-hybrid assay showed that PyMYB10 was associated with the -658 to -172bp fragment of the PpUFGT2 promoter, probably via a MYB binding site (MBS) located at -466bp. The PyMYB10 promoter had lower methylation levels in anthocyanin-rich tissues, indicating that the red bud sport of 'Zaosu' pear and the striped pigmentation pattern of 'Zaosu Red' pear are associated with demethylation of the PyMYB10 promoter.

  1. Flavonoid production in transgenic hop (Humulus lupulus L.) altered by PAP1/MYB75 from Arabidopsis thaliana L.

    PubMed

    Gatica-Arias, A; Farag, M A; Stanke, M; Matoušek, J; Wessjohann, L; Weber, G

    2012-01-01

    Hop is an important source of secondary metabolites, such as flavonoids. Some of these are pharmacologically active. Nevertheless, the concentration of some classes as flavonoids in wild-type plants is rather low. To enhance the production in hop, it would be interesting to modify the regulation of genes in the flavonoid biosynthetic pathway. For this purpose, the regulatory factor PAP1/AtMYB75 from Arabidopsis thaliana L. was introduced into hop plants cv. Tettnanger by Agrobacterium-mediated genetic transformation. Twenty kanamycin-resistant transgenic plants were obtained. It was shown that PAP1/AtMYB75 was stably incorporated and expressed in the hop genome. In comparison to the wild-type plants, the color of female flowers and cones of transgenic plants was reddish to pink. Chemical analysis revealed higher levels of anthocyanins, rutin, isoquercitin, kaempferol-glucoside, kaempferol-glucoside-malonate, desmethylxanthohumol, xanthohumol, α-acids and β-acids in transgenic plants compared to wild-type plants. PMID:21912858

  2. MicroRNA-15a and -16-1 act via MYB to elevate fetal hemoglobin expression in human trisomy 13.

    PubMed

    Sankaran, Vijay G; Menne, Tobias F; Šćepanović, Danilo; Vergilio, Jo-Anne; Ji, Peng; Kim, Jinkuk; Thiru, Prathapan; Orkin, Stuart H; Lander, Eric S; Lodish, Harvey F

    2011-01-25

    Many human aneuploidy syndromes have unique phenotypic consequences, but in most instances it is unclear whether these phenotypes are attributable to alterations in the dosage of specific genes. In human trisomy 13, there is delayed switching and persistence of fetal hemoglobin (HbF) and elevation of embryonic hemoglobin in newborns. Using partial trisomy cases, we mapped this trait to chromosomal band 13q14; by examining the genes in this region, two microRNAs, miR-15a and -16-1, appear as top candidates for the elevated HbF levels. Indeed, increased expression of these microRNAs in primary human erythroid progenitor cells results in elevated fetal and embryonic hemoglobin gene expression. Moreover, we show that a direct target of these microRNAs, MYB, plays an important role in silencing the fetal and embryonic hemoglobin genes. Thus we demonstrate how the developmental regulation of a clinically important human trait can be better understood through the genetic and functional study of aneuploidy syndromes and suggest that miR-15a, -16-1, and MYB may be important therapeutic targets to increase HbF levels in patients with sickle cell disease and β-thalassemia.

  3. Molecular Cloning Reveals that the p160 Myb-Binding Protein Is a Novel, Predominantly Nucleolar Protein Which May Play a Role in Transactivation by Myb

    PubMed Central

    Tavner, Fiona J.; Simpson, Richard; Tashiro, Shigeki; Favier, Diane; Jenkins, Nancy A.; Gilbert, Debra J.; Copeland, Neal G.; Macmillan, Elizabeth M.; Lutwyche, Jodi; Keough, Rebecca A.; Ishii, Shunsuke; Gonda, Thomas J.

    1998-01-01

    We have previously detected two related murine nuclear proteins, p160 and p67, that can bind to the leucine zipper motif within the negative regulatory domain of the Myb transcription factor. We now describe the molecular cloning of cDNA corresponding to murine p160. The P160 gene is located on mouse chromosome 11, and related sequences are found on chromosomes 1 and 12. The predicted p160 protein is novel, and in agreement with previous studies, we find that the corresponding 4.5-kb mRNA is ubiquitously expressed. We showed that p67 is an N-terminal fragment of p160 which is generated by proteolytic cleavage in certain cell types. The protein encoded by the cloned p160 cDNA and an engineered protein (p67*) comprising the amino-terminal region of p160 exhibit binding specificities for the Myb and Jun leucine zipper regions identical to those of endogenous p160 and p67, respectively. This implies that the Myb-binding site of p160 lies within the N-terminal 580 residues and that the Jun-binding site is C-terminal to this position. Moreover, we show that p67* but not p160 can inhibit transactivation by Myb. Unexpectedly, immunofluorescence studies show that p160 is localized predominantly in the nucleolus. The implications of these results for possible functions of p160 are discussed. PMID:9447996

  4. Regulation of Gene Expression in Protozoa Parasites

    PubMed Central

    Gomez, Consuelo; Esther Ramirez, M.; Calixto-Galvez, Mercedes; Medel, Olivia; Rodríguez, Mario A.

    2010-01-01

    Infections with protozoa parasites are associated with high burdens of morbidity and mortality across the developing world. Despite extensive efforts to control the transmission of these parasites, the spread of populations resistant to drugs and the lack of effective vaccines against them contribute to their persistence as major public health problems. Parasites should perform a strict control on the expression of genes involved in their pathogenicity, differentiation, immune evasion, or drug resistance, and the comprehension of the mechanisms implicated in that control could help to develop novel therapeutic strategies. However, until now these mechanisms are poorly understood in protozoa. Recent investigations into gene expression in protozoa parasites suggest that they possess many of the canonical machineries employed by higher eukaryotes for the control of gene expression at transcriptional, posttranscriptional, and epigenetic levels, but they also contain exclusive mechanisms. Here, we review the current understanding about the regulation of gene expression in Plasmodium sp., Trypanosomatids, Entamoeba histolytica and Trichomonas vaginalis. PMID:20204171

  5. GENE REGULATION BY MAPK SUBSTRATE COMPETITION

    PubMed Central

    Kim, Yoosik; Andreu, María José; Lim, Bomyi; Chung, Kwanghun; Terayama, Mark; Jiménez, Gerardo; Berg, Celeste A.; Lu, Hang; Shvartsman, Stanislav Y.

    2011-01-01

    SUMMARY Developing tissues are patterned by coordinated activities of signaling systems, which can be integrated by a regulatory region of a gene that binds multiple transcription factors or by a transcription factor that is modified by multiple enzymes. Based on a combination of genetic and imaging experiments in the early Drosophila embryo, we describe a signal integration mechanism that cannot be reduced to a single gene regulatory element or a single transcription factor. This mechanism relies on an enzymatic network formed by Mitogen Activated Protein Kinase (MAPK) and its substrates. Specifically, anteriorly localized MAPK substrates, such as Bicoid, antagonize MAPK-dependent downregulation of Capicua, a repressor which is involved in gene regulation along the dorsoventral axis of the embryo. MAPK substrate competition provides a basis for ternary interaction of the anterior, dorsoventral, and terminal patterning systems. A mathematical model of this interaction can explain gene expression patterns with both anteroposterior and dorsoventral polarities. PMID:21664584

  6. Arabidopsis CAPRICE (MYB) and GLABRA3 (bHLH) control tomato (Solanum lycopersicum) anthocyanin biosynthesis.

    PubMed

    Wada, Takuji; Kunihiro, Asuka; Tominaga-Wada, Rumi

    2014-01-01

    In Arabidopsis thaliana the MYB transcription factor CAPRICE (CPC) and the bHLH transcription factor GLABRA3 (GL3) are central regulators of root-hair differentiation and trichome initiation. By transforming the orthologous tomato genes SlTRY (CPC) and SlGL3 (GL3) into Arabidopsis, we demonstrated that these genes influence epidermal cell differentiation in Arabidopsis, suggesting that tomato and Arabidopsis partially use similar transcription factors for epidermal cell differentiation. CPC and GL3 are also known to be involved in anthocyanin biosynthesis. After transformation into tomato, 35S::CPC inhibited anthocyanin accumulation, whereas GL3::GL3 enhanced anthocyanin accumulation. Real-time reverse transcription PCR analyses showed that the expression of anthocyanin biosynthetic genes including Phe-ammonia lyase (PAL), the flavonoid pathway genes chalcone synthase (CHS), dihydroflavonol reductase (DFR), and anthocyanidin synthase (ANS) were repressed in 35S::CPC tomato. In contrast, the expression levels of PAL, CHS, DFR, and ANS were significantly higher in GL3::GL3 tomato compared with control plants. These results suggest that CPC and GL3 also influence anthocyanin pigment synthesis in tomato. PMID:25268379

  7. Arabidopsis CAPRICE (MYB) and GLABRA3 (bHLH) Control Tomato (Solanum lycopersicum) Anthocyanin Biosynthesis

    PubMed Central

    Wada, Takuji; Kunihiro, Asuka; Tominaga-Wada, Rumi

    2014-01-01

    In Arabidopsis thaliana the MYB transcription factor CAPRICE (CPC) and the bHLH transcription factor GLABRA3 (GL3) are central regulators of root-hair differentiation and trichome initiation. By transforming the orthologous tomato genes SlTRY (CPC) and SlGL3 (GL3) into Arabidopsis, we demonstrated that these genes influence epidermal cell differentiation in Arabidopsis, suggesting that tomato and Arabidopsis partially use similar transcription factors for epidermal cell differentiation. CPC and GL3 are also known to be involved in anthocyanin biosynthesis. After transformation into tomato, 35S::CPC inhibited anthocyanin accumulation, whereas GL3::GL3 enhanced anthocyanin accumulation. Real-time reverse transcription PCR analyses showed that the expression of anthocyanin biosynthetic genes including Phe-ammonia lyase (PAL), the flavonoid pathway genes chalcone synthase (CHS), dihydroflavonol reductase (DFR), and anthocyanidin synthase (ANS) were repressed in 35S::CPC tomato. In contrast, the expression levels of PAL, CHS, DFR, and ANS were significantly higher in GL3::GL3 tomato compared with control plants. These results suggest that CPC and GL3 also influence anthocyanin pigment synthesis in tomato. PMID:25268379

  8. Gene expression regulation in roots under drought.

    PubMed

    Janiak, Agnieszka; Kwaśniewski, Mirosław; Szarejko, Iwona

    2016-02-01

    Stress signalling and regulatory networks controlling expression of target genes are the basis of plant response to drought. Roots are the first organs exposed to water deficiency in the soil and are the place of drought sensing. Signalling cascades transfer chemical signals toward the shoot and initiate molecular responses that lead to the biochemical and morphological changes that allow plants to be protected against water loss and to tolerate stress conditions. Here, we present an overview of signalling network and gene expression regulation pathways that are actively induced in roots under drought stress. In particular, the role of several transcription factor (TF) families, including DREB, AP2/ERF, NAC, bZIP, MYC, CAMTA, Alfin-like and Q-type ZFP, in the regulation of root response to drought are highlighted. The information provided includes available data on mutual interactions between these TFs together with their regulation by plant hormones and other signalling molecules. The most significant downstream target genes and molecular processes that are controlled by the regulatory factors are given. These data are also coupled with information about the influence of the described regulatory networks on root traits and root development which may translate to enhanced drought tolerance. This is the first literature survey demonstrating the gene expression regulatory machinery that is induced by drought stress, presented from the perspective of roots.

  9. Transposable element origins of epigenetic gene regulation.

    PubMed

    Lisch, Damon; Bennetzen, Jeffrey L

    2011-04-01

    Transposable elements (TEs) are massively abundant and unstable in all plant genomes, but are mostly silent because of epigenetic suppression. Because all known epigenetic pathways act on all TEs, it is likely that the specialized epigenetic regulation of regular host genes (RHGs) was co-opted from this ubiquitous need for the silencing of TEs and viruses. With their internally repetitive and rearranging structures, and the acquisition of fragments of RHGs, the expression of TEs commonly makes antisense RNAs for both TE genes and RHGs. These antisense RNAs, particularly from heterochromatic reservoirs of 'zombie' TEs that are rearranged to form variously internally repetitive structures, may be advantageous because their induction will help rapidly suppress active TEs of the same family. RHG fragments within rapidly rearranging TEs may also provide the raw material for the ongoing generation of miRNA genes. TE gene expression is regulated by both environmental and developmental signals, and insertions can place nearby RHGs under the regulation (both standard and epigenetic) of the TE. The ubiquity of TEs, their frequent preferential association with RHGs, and their ability to be programmed by epigenetic signals all indicate that RGHs have nearly unlimited access to novel regulatory cassettes to assist plant adaptation. PMID:21444239

  10. IBD Candidate Genes and Intestinal Barrier Regulation

    PubMed Central

    McCole, Declan F.

    2015-01-01

    Technological advances in the large scale analysis of human genetics have generated profound insights into possible genetic contributions to chronic diseases including the inflammatory bowel diseases (IBDs), Crohn’s disease and ulcerative colitis. To date, 163 distinct genetic risk loci have been associated with either Crohn’s disease or ulcerative colitis, with a substantial degree of genetic overlap between these 2 conditions. Although many risk variants show a reproducible correlation with disease, individual gene associations only affect a subset of patients, and the functional contribution(s) of these risk variants to the onset of IBD is largely undetermined. Although studies in twins have demonstrated that the development of IBD is not mediated solely by genetic risk, it is nevertheless important to elucidate the functional consequences of risk variants for gene function in relevant cell types known to regulate key physiological processes that are compromised in IBD. This article will discuss IBD candidate genes that are known to be, or are suspected of being, involved in regulating the intestinal epithelial barrier and several of the physiological processes presided over by this dynamic and versatile layer of cells. This will include assembly and regulation of tight junctions, cell adhesion and polarity, mucus and glycoprotein regulation, bacterial sensing, membrane transport, epithelial differentiation, and restitution. PMID:25215613

  11. Linker histones in hormonal gene regulation.

    PubMed

    Vicent, G P; Wright, R H G; Beato, M

    2016-03-01

    In the present review, we summarize advances in our knowledge on the role of the histone H1 family of proteins in breast cancer cells, focusing on their response to progestins. Histone H1 plays a dual role in gene regulation by hormones, both as a structural component of chromatin and as a dynamic modulator of transcription. It contributes to hormonal regulation of the MMTV promoter by stabilizing a homogeneous nucleosome positioning, which reduces basal transcription whereas at the same time promoting progesterone receptor binding and nucleosome remodeling. These combined effects enhance hormone dependent gene transcription, which eventually requires H1 phosphorylation and displacement. Various isoforms of histone H1 have specific functions in differentiated breast cancer cells and compact nucleosomal arrays to different extents in vitro. Genome-wide studies show that histone H1 has a key role in chromatin dynamics of hormone regulated genes. A complex sequence of enzymatic events, including phosphorylation by CDK2, PARylation by PARP1 and the ATP-dependent activity of NURF, are required for H1 displacement and gene de-repression, as a prerequisite for further nucleosome remodeling. Similarly, during hormone-dependent gene repression a dedicated enzymatic mechanism controls H1 deposition at promoters by a complex containing HP1γ, LSD1 and BRG1, the ATPase of the BAF complex. Thus, a broader vision of the histone code should include histone H1, as the linker histone variants actively participate in the regulation of the chromatin structure. How modifications of the core histones tails affect H1 modifications and vice versa is one of the many questions that remains to be addressed to provide a more comprehensive view of the histone cross-talk mechanisms.

  12. Gene regulation and speciation in house mice

    PubMed Central

    Mack, Katya L.; Campbell, Polly; Nachman, Michael W.

    2016-01-01

    One approach to understanding the process of speciation is to characterize the genetic architecture of post-zygotic isolation. As gene regulation requires interactions between loci, negative epistatic interactions between divergent regulatory elements might underlie hybrid incompatibilities and contribute to reproductive isolation. Here, we take advantage of a cross between house mouse subspecies, where hybrid dysfunction is largely unidirectional, to test several key predictions about regulatory divergence and reproductive isolation. Regulatory divergence between Mus musculus musculus and M. m. domesticus was characterized by studying allele-specific expression in fertile hybrid males using mRNA-sequencing of whole testes. We found extensive regulatory divergence between M. m. musculus and M. m. domesticus, largely attributable to cis-regulatory changes. When both cis and trans changes occurred, they were observed in opposition much more often than expected under a neutral model, providing strong evidence of widespread compensatory evolution. We also found evidence for lineage-specific positive selection on a subset of genes related to transcriptional regulation. Comparisons of fertile and sterile hybrid males identified a set of genes that were uniquely misexpressed in sterile individuals. Lastly, we discovered a nonrandom association between these genes and genes showing evidence of compensatory evolution, consistent with the idea that regulatory interactions might contribute to Dobzhansky-Muller incompatibilities and be important in speciation. PMID:26833790

  13. Myb promotes centriole amplification and later steps of the multiciliogenesis program.

    PubMed

    Tan, Fraser E; Vladar, Eszter K; Ma, Lina; Fuentealba, Luis C; Hoh, Ramona; Espinoza, F Hernán; Axelrod, Jeffrey D; Alvarez-Buylla, Arturo; Stearns, Tim; Kintner, Chris; Krasnow, Mark A

    2013-10-01

    The transcriptional control of primary cilium formation and ciliary motility are beginning to be understood, but little is known about the transcriptional programs that control cilium number and other structural and functional specializations. One of the most intriguing ciliary specializations occurs in multiciliated cells (MCCs), which amplify their centrioles to nucleate hundreds of cilia per cell, instead of the usual monocilium. Here we report that the transcription factor MYB, which promotes S phase and drives cycling of a variety of progenitor cells, is expressed in postmitotic epithelial cells of the mouse airways and ependyma destined to become MCCs. MYB is expressed early in multiciliogenesis, as progenitors exit the cell cycle and amplify their centrioles, then switches off as MCCs mature. Conditional inactivation of Myb in the developing airways blocks or delays centriole amplification and expression of FOXJ1, a transcription factor that controls centriole docking and ciliary motility, and airways fail to become fully ciliated. We provide evidence that MYB acts in a conserved pathway downstream of Notch signaling and multicilin, a protein related to the S-phase regulator geminin, and upstream of FOXJ1. MYB can activate endogenous Foxj1 expression and stimulate a cotransfected Foxj1 reporter in heterologous cells, and it can drive the complete multiciliogenesis program in Xenopus embryonic epidermis. We conclude that MYB has an early, crucial and conserved role in multiciliogenesis, and propose that it promotes a novel S-like phase in which centriole amplification occurs uncoupled from DNA synthesis, and then drives later steps of multiciliogenesis through induction of Foxj1.

  14. CmWRKY1 Enhances the Dehydration Tolerance of Chrysanthemum through the Regulation of ABA-Associated Genes.

    PubMed

    Fan, Qingqing; Song, Aiping; Jiang, Jiafu; Zhang, Ting; Sun, Hainan; Wang, Yinjie; Chen, Sumei; Chen, Fadi

    2016-01-01

    WRKY transcription factors serve as antagonistic or synergistic regulators in a variety of abiotic stress responses in plants. Here, we show that CmWRKY1, a member of the group IIb WRKY family isolated from Chrysanthemum morifolium, exhibits no transcriptional activation in yeast cells. The subcellular localization examination showed that CmWRKY1 localizes to the nucleus in vivo. Furthermore, CmWRKY1-overexpressing transgenic lines exhibit enhanced dehydration tolerance in response to polyethylene glycol (PEG) treatment compared with wild-type plants. We further confirmed that the transgenic plants exhibit suppressed expression levels of genes negatively regulated by ABA, such as PP2C, ABI1 and ABI2, and activated expression levels of genes positively regulated by ABA, such as PYL2, SnRK2.2, ABF4, MYB2, RAB18, and DREB1A. Taken together, our results indicate that CmWRKY1 plays an important role in the response to drought in chrysanthemum through an ABA-mediated pathway. PMID:26938878

  15. CmWRKY1 Enhances the Dehydration Tolerance of Chrysanthemum through the Regulation of ABA-Associated Genes

    PubMed Central

    Fan, Qingqing; Song, Aiping; Jiang, Jiafu; Zhang, Ting; Sun, Hainan; Wang, Yinjie; Chen, Sumei; Chen, Fadi

    2016-01-01

    WRKY transcription factors serve as antagonistic or synergistic regulators in a variety of abiotic stress responses in plants. Here, we show that CmWRKY1, a member of the group IIb WRKY family isolated from Chrysanthemum morifolium, exhibits no transcriptional activation in yeast cells. The subcellular localization examination showed that CmWRKY1 localizes to the nucleus in vivo. Furthermore, CmWRKY1-overexpressing transgenic lines exhibit enhanced dehydration tolerance in response to polyethylene glycol (PEG) treatment compared with wild-type plants. We further confirmed that the transgenic plants exhibit suppressed expression levels of genes negatively regulated by ABA, such as PP2C, ABI1 and ABI2, and activated expression levels of genes positively regulated by ABA, such as PYL2, SnRK2.2, ABF4, MYB2, RAB18, and DREB1A. Taken together, our results indicate that CmWRKY1 plays an important role in the response to drought in chrysanthemum through an ABA-mediated pathway. PMID:26938878

  16. Regulation of gene expression by hypoxia.

    PubMed

    Kenneth, Niall Steven; Rocha, Sonia

    2008-08-15

    Hypoxia induces profound changes in the cellular gene expression profile. The discovery of a major transcription factor family activated by hypoxia, HIF (hypoxia-inducible factor), and the factors that contribute to HIF regulation have greatly enhanced our knowledge of the molecular aspects of the hypoxic response. However, in addition to HIF, other transcription factors and cellular pathways are activated by exposure to reduced oxygen. In the present review, we summarize the current knowledge of how additional hypoxia-responsive transcription factors integrate with HIF and how other cellular pathways such as chromatin remodelling, translation regulation and microRNA induction, contribute to the co-ordinated cellular response observed following hypoxic stress.

  17. Insertional activation of myb by F-MuLV in SCID mice induces myeloid leukemia.

    PubMed

    Haeri, Mehran; Li, Youjun; Li, Yanmei; Li, Qi; Spaner, David E; Ben-David, Yaacov

    2013-07-01

    Identification of retrovirus integration sites is a powerful method to identify cancer-related genes. This approach led to the discovery of the Friend murine leukemia virus (F-MuLV) integration site-1 (fli-1). Viral insertion at the fli-1 locus induces erythroleukemia in susceptible strains of mice. Our recent data demonstrated that, F-MuLV-infected SCID mice, in contrast to wt CB17 controls, developed a non‑erythroleukemic leukemia without viral integration at the fli-1 locus. Using ligation-mediated polymerase chain reaction (LM-PCR) approach we identified a total of 15 viral integration sites in F-MuLV-infected SCID mice. One of the identified insertion sites was located about 62 kb upstream of the myeloblastosis (myb) gene. While integration within or surrounding the myb gene has been reported before for murine leukemia viruses, the location of the viral integration site identified in F-MuLV‑infected SCID mice is novel and has never been reported. Using PCR analysis we showed that viral integration at the myb locus occurs with a frequency of 35% and therefore is considered as a common integration site. Integration of F-MuLV in this locus resulted in upregulation of the MYB protein. Flow cytometry analysis and methylcellulose culture of leukemic cells isolated from tumors with viral integration close to the myb indicated tumors of myeloid origin. Our findings indicate that, in contrast to wt CB17 mice, F-MuLV-infected SCID mice display viral integration within myeloid specific gene loci that result in the development of myelogenous leukemia.

  18. Combinatorial Transcription Control in Gene Regulation

    NASA Astrophysics Data System (ADS)

    Hwa, Terence; Buchler, Nicolas E.; Gerland, Ulrich

    2003-03-01

    We develop a simple thermodynamic model for the regulation of gene transcription and explore the limits of combinatorial control. Our model is based on the ``regulated recruitment'' mechanism [M. Ptashne and A. Gann, Nature 386 (1997) 569], assuming weak contact interaction between the regulatory proteins together with specific protein-DNA interactions. We further assume "programmability" in the strengths of these interactions within a biophysically allowed range [U. Gerland, J.D. Moroz, and T.Hwa, PNAS 99 (2002) 12015], through the choices and the locations of the protein-binding DNA sequences in the regulatory region. Within our thermodynamic model, we demonstrate the implementability of various binary logic functions (including XOR) by computing the degree of gene transcription (output) for all combinations of regulatory protein concentrations (input).

  19. Regulation of methane genes and genome expression

    SciTech Connect

    John N. Reeve

    2009-09-09

    At the start of this project, it was known that methanogens were Archaeabacteria (now Archaea) and were therefore predicted to have gene expression and regulatory systems different from Bacteria, but few of the molecular biology details were established. The goals were then to establish the structures and organizations of genes in methanogens, and to develop the genetic technologies needed to investigate and dissect methanogen gene expression and regulation in vivo. By cloning and sequencing, we established the gene and operon structures of all of the “methane” genes that encode the enzymes that catalyze methane biosynthesis from carbon dioxide and hydrogen. This work identified unique sequences in the methane gene that we designated mcrA, that encodes the largest subunit of methyl-coenzyme M reductase, that could be used to identify methanogen DNA and establish methanogen phylogenetic relationships. McrA sequences are now the accepted standard and used extensively as hybridization probes to identify and quantify methanogens in environmental research. With the methane genes in hand, we used northern blot and then later whole-genome microarray hybridization analyses to establish how growth phase and substrate availability regulated methane gene expression in Methanobacterium thermautotrophicus ΔH (now Methanothermobacter thermautotrophicus). Isoenzymes or pairs of functionally equivalent enzymes catalyze several steps in the hydrogen-dependent reduction of carbon dioxide to methane. We established that hydrogen availability determine which of these pairs of methane genes is expressed and therefore which of the alternative enzymes is employed to catalyze methane biosynthesis under different environmental conditions. As were unable to establish a reliable genetic system for M. thermautotrophicus, we developed in vitro transcription as an alternative system to investigate methanogen gene expression and regulation. This led to the discovery that an archaeal protein

  20. Coactivators in PPAR-Regulated Gene Expression

    PubMed Central

    Viswakarma, Navin; Jia, Yuzhi; Bai, Liang; Vluggens, Aurore; Borensztajn, Jayme; Xu, Jianming; Reddy, Janardan K.

    2010-01-01

    Peroxisome proliferator-activated receptor (PPAR)α, β (also known as δ), and γ function as sensors for fatty acids and fatty acid derivatives and control important metabolic pathways involved in the maintenance of energy balance. PPARs also regulate other diverse biological processes such as development, differentiation, inflammation, and neoplasia. In the nucleus, PPARs exist as heterodimers with retinoid X receptor-α bound to DNA with corepressor molecules. Upon ligand activation, PPARs undergo conformational changes that facilitate the dissociation of corepressor molecules and invoke a spatiotemporally orchestrated recruitment of transcription cofactors including coactivators and coactivator-associated proteins. While a given nuclear receptor regulates the expression of a prescribed set of target genes, coactivators are likely to influence the functioning of many regulators and thus affect the transcription of many genes. Evidence suggests that some of the coactivators such as PPAR-binding protein (PBP/PPARBP), thyroid hormone receptor-associated protein 220 (TRAP220), and mediator complex subunit 1 (MED1) may exert a broader influence on the functions of several nuclear receptors and their target genes. Investigations into the role of coactivators in the function of PPARs should strengthen our understanding of the complexities of metabolic diseases associated with energy metabolism. PMID:20814439

  1. Regulation of gene expression in human tendinopathy

    PubMed Central

    2011-01-01

    Background Chronic tendon injuries, also known as tendinopathies, are common among professional and recreational athletes. These injuries result in a significant amount of morbidity and health care expenditure, yet little is known about the molecular mechanisms leading to tendinopathy. Methods We have used histological evaluation and molecular profiling to determine gene expression changes in 23 human patients undergoing surgical procedures for the treatment of chronic tendinopathy. Results Diseased tendons exhibit altered extracellular matrix, fiber disorientation, increased cellular content and vasculature, and the absence of inflammatory cells. Global gene expression profiling identified 983 transcripts with significantly different expression patterns in the diseased tendons. Global pathway analysis further suggested altered expression of extracellular matrix proteins and the lack of an appreciable inflammatory response. Conclusions Identification of the pathways and genes that are differentially regulated in tendinopathy samples will contribute to our understanding of the disease and the development of novel therapeutics. PMID:21539748

  2. Gene therapy on demand: site specific regulation of gene therapy.

    PubMed

    Jazwa, Agnieszka; Florczyk, Urszula; Jozkowicz, Alicja; Dulak, Jozef

    2013-08-10

    Since 1990 when the first clinical gene therapy trial was conducted, much attention and considerable promise have been given to this form of treatment. Gene therapy has been used with success in patients suffering from severe combined immunodeficiency syndromes (X-SCID and ADA-deficiency), Leber's congenital amaurosis, hemophilia, β-thalassemia and adrenoleukodystrophy. Last year, the first therapeutic vector (Glybera) for treatment of lipoprotein lipase deficiency has been registered in the European Union. Nevertheless, there are still several numerous issues that need to be improved to make this technique more safe, effective and easily accessible for patients. Introduction of the therapeutic gene to the given cells should provide the level of expression which will restore the production of therapeutic protein to normal values or will provide therapeutic efficacy despite not fully physiological expression. However, in numerous diseases the expression of therapeutic genes has to be kept at certain level for some time, and then might be required to be switched off to be activated again when worsening of the symptoms may aggravate the risk of disease relapse. In such cases the promoters which are regulated by local conditions may be more required. In this article the special emphasis is to discuss the strategies of regulation of gene expression by endogenous stimuli. Particularly, the hypoxia- or miRNA-regulated vectors offer the possibilities of tight but, at the same time, condition-dependent and cell-specific expression. Such means have been already tested in certain pathophysiological conditions. This creates the chance for the translational approaches required for development of effective treatments of so far incurable diseases. PMID:23566848

  3. Gene regulation in parthenocarpic tomato fruit.

    PubMed

    Martinelli, Federico; Uratsu, Sandra L; Reagan, Russell L; Chen, Ying; Tricoli, David; Fiehn, Oliver; Rocke, David M; Gasser, Charles S; Dandekar, Abhaya M

    2009-01-01

    Parthenocarpy is potentially a desirable trait for many commercially grown fruits if undesirable changes to structure, flavour, or nutrition can be avoided. Parthenocarpic transgenic tomato plants (cv MicroTom) were obtained by the regulation of genes for auxin synthesis (iaaM) or responsiveness (rolB) driven by DefH9 or the INNER NO OUTER (INO) promoter from Arabidopsis thaliana. Fruits at a breaker stage were analysed at a transcriptomic and metabolomic level using microarrays, real-time reverse transcription-polymerase chain reaction (RT-PCR) and a Pegasus III TOF (time of flight) mass spectrometer. Although differences were observed in the shape of fully ripe fruits, no clear correlation could be made between the number of seeds, transgene, and fruit size. Expression of auxin synthesis or responsiveness genes by both of these promoters produced seedless parthenocarpic fruits. Eighty-three percent of the genes measured showed no significant differences in expression due to parthenocarpy. The remaining 17% with significant variation (P <0.05) (1748 genes) were studied by assigning a predicted function (when known) based on BLAST to the TAIR database. Among them several genes belong to cell wall, hormone metabolism and response (auxin in particular), and metabolism of sugars and lipids. Up-regulation of lipid transfer proteins and differential expression of several indole-3-acetic acid (IAA)- and ethylene-associated genes were observed in transgenic parthenocarpic fruits. Despite differences in several fatty acids, amino acids, and other metabolites, the fundamental metabolic profile remains unchanged. This work showed that parthenocarpy with ovule-specific alteration of auxin synthesis or response driven by the INO promoter could be effectively applied where such changes are commercially desirable. PMID:19700496

  4. Cloning and characteristic analysis of a novel aspartic protease gene Asp55 from Trichoderma asperellum ACCC30536.

    PubMed

    Dou, Kai; Wang, Zhiying; Zhang, Rongshu; Wang, Na; Fan, Haijuan; Diao, Guiping; Liu, Zhihua

    2014-12-01

    Proteases secreted by fungi belonging to the genus Trichoderma play important roles in biocontrol. In this study, the coding sequence and promoter region of the novel aspartic protease gene Asp55 were cloned from strain Trichoderma asperellum ACCC30536. Many cis-elements involved in phytopathogenic and environmental stress responses were identified in the Asp55 promoter region and may be recognized by MYB or WRKY transcription factors. The expression pattern of Asp55 under eight culture conditions was investigated by RT-qPCR. The expression level of Asp55 was up-regulated by poplar stem powder, Alternaria alternata cell wall fragments and A. alternata fermentation liquid, while it was down-regulated by carbon and nitrogen source starvation, and by powdered poplar leaves and roots. Additionally, the expression patterns of 15 genes encoding MYB transcription factors (Myb1 to Myb15) were also analyzed by RT-qPCR. Myb2 showed the most similar expression pattern with Asp55. The cDNA of Asp55 was expressed in Escherichia coli BL21, and recombinant ASP55 (rASP55) was purified. The purified rASP55 was evaluated for enzymatic activity and showed inhibitory effect on phytopathogenic A. alternata.

  5. A sorghum MYB transcription factor induces 3-deoxyanthocyanidins and enhances resistance against leaf blights in maize.

    PubMed

    Ibraheem, Farag; Gaffoor, Iffa; Tan, Qixian; Shyu, Chi-Ren; Chopra, Surinder

    2015-01-01

    Sorghum responds to the ingress of the fungal pathogen Colletotrichum sublineolum through the biosynthesis of 3-deoxyanthocyanidin phytoalexins at the site of primary infection. Biosynthesis of 3-deoxyanthocyanidins in sorghum requires a MYB transcription factor encoded by yellow seed1 (y1), an orthologue of the maize gene pericarp color1 (p1). Maize lines with a functional p1 and flavonoid structural genes do not produce foliar 3-deoxyanthocyanidins in response to fungal ingress. To perform a comparative metabolic analysis of sorghum and maize 3-deoxyanthocyanidin biosynthetic pathways, we developed transgenic maize lines expressing the sorghum y1 gene. In maize, the y1 transgene phenocopied p1-regulated pigment accumulation in the pericarp and cob glumes. LC-MS profiling of fungus-challenged Y1-maize leaves showed induction of 3-deoxyanthocyanidins, specifically luteolinidin. Y1-maize plants also induced constitutive and higher levels of flavonoids in leaves. In response to Colletotrichum graminicola, Y1-maize showed a resistance response. PMID:25647576

  6. Trace concentrations of imazethapyr (IM) affect floral organs development and reproduction in Arabidopsis thaliana: IM-induced inhibition of key genes regulating anther and pollen biosynthesis.

    PubMed

    Qian, Haifeng; Li, Yali; Sun, Chongchong; Lavoie, Michel; Xie, Jun; Bai, Xiaocui; Fu, Zhengwei

    2015-01-01

    Understanding how herbicides affect plant reproduction and growth is critical to develop herbicide toxicity model and refine herbicide risk assessment. Although our knowledge of herbicides toxicity mechanisms at the physiological and molecular level in plant vegetative phase has increased substantially in the last decades, few studies have addressed the herbicide toxicity problematic on plant reproduction. Here, we determined the long-term (4-8 weeks) effect of a chiral herbicide, imazethapyr (IM), which has been increasingly used in plant crops, on floral organ development and reproduction in the model plant Arabidopsis thaliana. More specifically, we followed the effect of two IM enantiomers (R- and S-IM) on floral organ structure, seed production, pollen viability and the transcription of key genes involved in anther and pollen development. The results showed that IM strongly inhibited the transcripts of genes regulating A. thaliana tapetum development (DYT1: DYSFUNCTIONAL TAPETUM 1), tapetal differentiation and function (TDF1: TAPETAL DEVELOPMENT AND FUNCTION1), and pollen wall formation and developments (AMS: ABORTED MICROSPORES, MYB103: MYB DOMAIN PROTEIN 103, MS1: MALE STERILITY 1, MS2: MALE STERILITY 2). Since DYT1 positively regulates 33 genes involved in cell-wall modification (such as, TDF1, AMS, MYB103, MS1, MS2) that can catalyze the breakdown of polysaccharides to facilitate anther dehiscence, the consistent decrease in the transcription of these genes after IM exposure should hamper anther opening as observed under scanning electron microscopy. The toxicity of IM on anther opening further lead to a decrease in pollen production and pollen viability. Furthermore, long-term IM exposure increased the number of apurinic/apyrimidinic sites (AP sites) in the DNA of A. thaliana and also altered the DNA of A. thaliana offspring grown in IM-free soils. Toxicity of IM on floral organs development and reproduction was generally higher in the presence of the R

  7. Purple foliage coloration in tea (Camellia sinensis L.) arises from activation of the R2R3-MYB transcription factor CsAN1.

    PubMed

    Sun, Binmei; Zhu, Zhangsheng; Cao, Panrong; Chen, Hao; Chen, Changming; Zhou, Xin; Mao, Yanhui; Lei, Jianjun; Jiang, Yanpin; Meng, Wei; Wang, Yingxi; Liu, Shaoqun

    2016-09-01

    Purple foliage always appears in Camellia sinensis families; however, the transcriptional regulation of anthocyanin biosynthesis is unknown. The tea bud sport cultivar 'Zijuan' confers an abnormal pattern of anthocyanin accumulation, resulting in a mutant phenotype that has a striking purple color in young foliage and in the stem. In this study, we aimed to unravel the underlying molecular mechanism of anthocyanin biosynthetic regulation in C. sinensis. Our results revealed that activation of the R2R3-MYB transcription factor (TF) anthocyanin1 (CsAN1) specifically upregulated the bHLH TF CsGL3 and anthocyanin late biosynthetic genes (LBGs) to confer ectopic accumulation of pigment in purple tea. We found CsAN1 interacts with bHLH TFs (CsGL3 and CsEGL3) and recruits a WD-repeat protein CsTTG1 to form the MYB-bHLH-WDR (MBW) complex that regulates anthocyanin accumulation. We determined that the hypomethylation of a CpG island in the CsAN1 promoter is associated with the purple phenotype. Furthermore, we demonstrated that low temperature and long illumination induced CsAN1 promoter demethylation, resulting in upregulated expression to promote anthocyanin accumulation in the foliage. The successful isolation of CsAN1 provides important information on the regulatory control of anthocyanin biosynthesis in C. sinensis and offers a genetic resource for the development of new varieties with enhanced anthocyanin content.

  8. Purple foliage coloration in tea (Camellia sinensis L.) arises from activation of the R2R3-MYB transcription factor CsAN1.

    PubMed

    Sun, Binmei; Zhu, Zhangsheng; Cao, Panrong; Chen, Hao; Chen, Changming; Zhou, Xin; Mao, Yanhui; Lei, Jianjun; Jiang, Yanpin; Meng, Wei; Wang, Yingxi; Liu, Shaoqun

    2016-01-01

    Purple foliage always appears in Camellia sinensis families; however, the transcriptional regulation of anthocyanin biosynthesis is unknown. The tea bud sport cultivar 'Zijuan' confers an abnormal pattern of anthocyanin accumulation, resulting in a mutant phenotype that has a striking purple color in young foliage and in the stem. In this study, we aimed to unravel the underlying molecular mechanism of anthocyanin biosynthetic regulation in C. sinensis. Our results revealed that activation of the R2R3-MYB transcription factor (TF) anthocyanin1 (CsAN1) specifically upregulated the bHLH TF CsGL3 and anthocyanin late biosynthetic genes (LBGs) to confer ectopic accumulation of pigment in purple tea. We found CsAN1 interacts with bHLH TFs (CsGL3 and CsEGL3) and recruits a WD-repeat protein CsTTG1 to form the MYB-bHLH-WDR (MBW) complex that regulates anthocyanin accumulation. We determined that the hypomethylation of a CpG island in the CsAN1 promoter is associated with the purple phenotype. Furthermore, we demonstrated that low temperature and long illumination induced CsAN1 promoter demethylation, resulting in upregulated expression to promote anthocyanin accumulation in the foliage. The successful isolation of CsAN1 provides important information on the regulatory control of anthocyanin biosynthesis in C. sinensis and offers a genetic resource for the development of new varieties with enhanced anthocyanin content. PMID:27581206

  9. Purple foliage coloration in tea (Camellia sinensis L.) arises from activation of the R2R3-MYB transcription factor CsAN1

    PubMed Central

    Sun, Binmei; Zhu, Zhangsheng; Cao, Panrong; Chen, Hao; Chen, Changming; Zhou, Xin; Mao, Yanhui; Lei, Jianjun; Jiang, Yanpin; Meng, Wei; Wang, Yingxi; Liu, Shaoqun

    2016-01-01

    Purple foliage always appears in Camellia sinensis families; however, the transcriptional regulation of anthocyanin biosynthesis is unknown. The tea bud sport cultivar ‘Zijuan’ confers an abnormal pattern of anthocyanin accumulation, resulting in a mutant phenotype that has a striking purple color in young foliage and in the stem. In this study, we aimed to unravel the underlying molecular mechanism of anthocyanin biosynthetic regulation in C. sinensis. Our results revealed that activation of the R2R3-MYB transcription factor (TF) anthocyanin1 (CsAN1) specifically upregulated the bHLH TF CsGL3 and anthocyanin late biosynthetic genes (LBGs) to confer ectopic accumulation of pigment in purple tea. We found CsAN1 interacts with bHLH TFs (CsGL3 and CsEGL3) and recruits a WD-repeat protein CsTTG1 to form the MYB-bHLH-WDR (MBW) complex that regulates anthocyanin accumulation. We determined that the hypomethylation of a CpG island in the CsAN1 promoter is associated with the purple phenotype. Furthermore, we demonstrated that low temperature and long illumination induced CsAN1 promoter demethylation, resulting in upregulated expression to promote anthocyanin accumulation in the foliage. The successful isolation of CsAN1 provides important information on the regulatory control of anthocyanin biosynthesis in C. sinensis and offers a genetic resource for the development of new varieties with enhanced anthocyanin content. PMID:27581206

  10. Gene and genon concept: coding versus regulation

    PubMed Central

    2007-01-01

    We analyse here the definition of the gene in order to distinguish, on the basis of modern insight in molecular biology, what the gene is coding for, namely a specific polypeptide, and how its expression is realized and controlled. Before the coding role of the DNA was discovered, a gene was identified with a specific phenotypic trait, from Mendel through Morgan up to Benzer. Subsequently, however, molecular biologists ventured to define a gene at the level of the DNA sequence in terms of coding. As is becoming ever more evident, the relations between information stored at DNA level and functional products are very intricate, and the regulatory aspects are as important and essential as the information coding for products. This approach led, thus, to a conceptual hybrid that confused coding, regulation and functional aspects. In this essay, we develop a definition of the gene that once again starts from the functional aspect. A cellular function can be represented by a polypeptide or an RNA. In the case of the polypeptide, its biochemical identity is determined by the mRNA prior to translation, and that is where we locate the gene. The steps from specific, but possibly separated sequence fragments at DNA level to that final mRNA then can be analysed in terms of regulation. For that purpose, we coin the new term “genon”. In that manner, we can clearly separate product and regulative information while keeping the fundamental relation between coding and function without the need to introduce a conceptual hybrid. In mRNA, the program regulating the expression of a gene is superimposed onto and added to the coding sequence in cis - we call it the genon. The complementary external control of a given mRNA by trans-acting factors is incorporated in its transgenon. A consequence of this definition is that, in eukaryotes, the gene is, in most cases, not yet present at DNA level. Rather, it is assembled by RNA processing, including differential splicing, from various

  11. Exploring the mechanism of how tvMyb2 recognizes and binds ap65-1 by molecular dynamics simulations and free energy calculations.

    PubMed

    Li, Wei-Kang; Zheng, Qing-Chuan; Zhang, Hong-Xing

    2016-01-01

    TvMyb2, one of the Myb-like transcriptional factors in Trichomonas vaginalis, binds to two closely spaced promoter sites, MRE-1/MRE-2r and MRE-2f, on the ap65-1 gene. However, detailed dynamical structural characteristics of the tvMyb2-ap65-1 complex and a detailed study of the protein in the complex have not been done. Focused on a specific tvMyb2-MRE-2-13 complex (PDB code: ) and a series of mutants K51A, R84A and R87A, we applied molecular dynamics (MD) simulation and molecular mechanics generalized Born surface area (MM-GBSA) free energy calculations to examine the role of the tvMyb2 protein in recognition interaction. The simulation results indicate that tvMyb2 becomes stable when it binds the DNA duplex. A series of mutants, K51A, R84A and R87A, have been followed, and the results of statistical analyses of the H-bond and hydrophobic contacts show that some residues have significant influence on recognition and binding to ap65-1 DNA. Our work gives important information to understand the interactions of tvMyb2 with ap65-1. PMID:26548411

  12. Following the Footsteps of Chlamydial Gene Regulation

    PubMed Central

    Domman, D.; Horn, M.

    2015-01-01

    Regulation of gene expression ensures an organism responds to stimuli and undergoes proper development. Although the regulatory networks in bacteria have been investigated in model microorganisms, nearly nothing is known about the evolution and plasticity of these networks in obligate, intracellular bacteria. The phylum Chlamydiae contains a vast array of host-associated microbes, including several human pathogens. The Chlamydiae are unique among obligate, intracellular bacteria as they undergo a complex biphasic developmental cycle in which large swaths of genes are temporally regulated. Coupled with the low number of transcription factors, these organisms offer a model to study the evolution of regulatory networks in intracellular organisms. We provide the first comprehensive analysis exploring the diversity and evolution of regulatory networks across the phylum. We utilized a comparative genomics approach to construct predicted coregulatory networks, which unveiled genus- and family-specific regulatory motifs and architectures, most notably those of virulence-associated genes. Surprisingly, our analysis suggests that few regulatory components are conserved across the phylum, and those that are conserved are involved in the exploitation of the intracellular niche. Our study thus lends insight into a component of chlamydial evolution that has otherwise remained largely unexplored. PMID:26424812

  13. Melatonin Improved Anthocyanin Accumulation by Regulating Gene Expressions and Resulted in High Reactive Oxygen Species Scavenging Capacity in Cabbage.

    PubMed

    Zhang, Na; Sun, Qianqian; Li, Hongfei; Li, Xingsheng; Cao, Yunyun; Zhang, Haijun; Li, Shuangtao; Zhang, Lei; Qi, Yan; Ren, Shuxin; Zhao, Bing; Guo, Yang-Dong

    2016-01-01

    In this work, we found, that exogenous melatonin pretreatment improved anthocyanin accumulation (1- to 2-fold) in cabbage. To verify the relationship with melatonin and anthocyanin, an Arabidopsis mutant, snat, which expresses a defective form of the melatonin biosynthesis enzyme SNAT (Serotonin N-acetyl transferase), was employed. Under cold conditions, the foliage of wild-type Arabidopsis exhibited a deeper red color than the snat mutant. This finding further proved, that exogenous melatonin treatment was able to affect anthocyanin accumulation. To gain a better understanding of how exogenous melatonin upregulates anthocyanin, we measured gene expression in cabbage samples treated with melatonin and untreated controls. We found that the transcript levels of anthocyanin biosynthetic genes were upregulated by melatonin treatment. Moreover, melatonin treatment increased the expression levels of the transcription factors MYB, bHLH, and WD40, which constitute the transcriptional activation complex responsible for coordinative regulation of anthocyanin biosynthetic genes. We found, that free radical generation was downregulated, whereas the osmotic adjustment and antioxidant capacities were upregulated in exogenous melatonin-treated cabbage plants. We concluded, that melatonin increases anthocyanin production and benefits cabbage growth. PMID:27047496

  14. Melatonin Improved Anthocyanin Accumulation by Regulating Gene Expressions and Resulted in High Reactive Oxygen Species Scavenging Capacity in Cabbage

    PubMed Central

    Zhang, Na; Sun, Qianqian; Li, Hongfei; Li, Xingsheng; Cao, Yunyun; Zhang, Haijun; Li, Shuangtao; Zhang, Lei; Qi, Yan; Ren, Shuxin; Zhao, Bing; Guo, Yang-Dong

    2016-01-01

    In this work, we found, that exogenous melatonin pretreatment improved anthocyanin accumulation (1- to 2-fold) in cabbage. To verify the relationship with melatonin and anthocyanin, an Arabidopsis mutant, snat, which expresses a defective form of the melatonin biosynthesis enzyme SNAT (Serotonin N-acetyl transferase), was employed. Under cold conditions, the foliage of wild-type Arabidopsis exhibited a deeper red color than the snat mutant. This finding further proved, that exogenous melatonin treatment was able to affect anthocyanin accumulation. To gain a better understanding of how exogenous melatonin upregulates anthocyanin, we measured gene expression in cabbage samples treated with melatonin and untreated controls. We found that the transcript levels of anthocyanin biosynthetic genes were upregulated by melatonin treatment. Moreover, melatonin treatment increased the expression levels of the transcription factors MYB, bHLH, and WD40, which constitute the transcriptional activation complex responsible for coordinative regulation of anthocyanin biosynthetic genes. We found, that free radical generation was downregulated, whereas the osmotic adjustment and antioxidant capacities were upregulated in exogenous melatonin-treated cabbage plants. We concluded, that melatonin increases anthocyanin production and benefits cabbage growth. PMID:27047496

  15. Retrotransposons as regulators of gene expression.

    PubMed

    Elbarbary, Reyad A; Lucas, Bronwyn A; Maquat, Lynne E

    2016-02-12

    Transposable elements (TEs) are both a boon and a bane to eukaryotic organisms, depending on where they integrate into the genome and how their sequences function once integrated. We focus on two types of TEs: long interspersed elements (LINEs) and short interspersed elements (SINEs). LINEs and SINEs are retrotransposons; that is, they transpose via an RNA intermediate. We discuss how LINEs and SINEs have expanded in eukaryotic genomes and contribute to genome evolution. An emerging body of evidence indicates that LINEs and SINEs function to regulate gene expression by affecting chromatin structure, gene transcription, pre-mRNA processing, or aspects of mRNA metabolism. We also describe how adenosine-to-inosine editing influences SINE function and how ongoing retrotransposition is countered by the body's defense mechanisms.