scholarly journals Comprehensive Influences of Overexpression of a MYB Transcriptor Regulating Anthocyanin Biosynthesis on Transcriptome and Metabolome of Tobacco Leaves

2019 ◽  
Vol 20 (20) ◽  
pp. 5123 ◽  
Author(s):  
Yuan Zong ◽  
Shiming Li ◽  
Xinyuan Xi ◽  
Dong Cao ◽  
Zhong Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Anthocyanin Biosynthesis ◽  
Chemical Compounds ◽  
Phenylpropanoid Pathway ◽  
Myb Transcription Factor ◽  
Regulation Mechanism ◽  
Anthocyanin Content ◽  
Biosynthesis Pathway ◽  
Structural Genes ◽  
Transgenic Lines

Overexpression of R2R3-MYB transcriptor can induce up-expression of anthocyanin biosynthesis structural genes, and improve the anthocyanin content in plant tissues, but it is not clear whether the MYB transcription factor overexpression does effect on other genes transcript and chemical compounds accumulation. In this manuscript, RNA-sequencing and the stepwise multiple ion monitoring-enhanced product ions (stepwise MIM-EPI) strategy were employed to evaluate the comprehensive effect of the MYB transcription factor LrAN2 in tobacco. Overexpression of LrAN2 could promote anthocyanin accumulation in a lot of tissues of tobacco cultivar Samsun. Only 185 unigenes express differently in a total of 160,965 unigenes in leaves, and 224 chemical compounds were differently accumulated. Three anthocyanins, apigeninidin chloride, pelargonidin 3-O-beta-D-glucoside and cyanidin 3,5-O-diglucoside, were detected only in transgenic lines, which could explain the phenotype of purple leaves. Except for anthocyanins, the phenylpropanoid, polyphenol (catechin), flavonoid, flavone and flavonol, belong to the same subgroups of flavonoids biosynthesis pathway with anthocyanin and were also up-accumulated. Overexpression of LrAN2 activated the bHLH (basic helix-loop-helix protein) transcription factor AN1b, relative to anthocyanin biosynthesis and the MYB transcription factor MYB3, relative to proanthocyanin biosynthesis. Then, the structural genes, relative to the phenylpropanoid pathway, were activated, which led to the up-accumulation of phenylpropanoid, polyphenol (catechin), flavonoid, flavone, flavonol and anthocyanin. The MYB transcription factor CPC, negative to anthocyanin biosynthesis, also induced up-expression in transgenic lines, which implied that a negative regulation mechanism existed in the anthocyanin biosynthesis pathway. The relative contents of all 19 differently accumulated amino and derivers were decreased in transgenic lines, which meant the phenylalanine biosynthesis pathway completed the same substrates with other amino acids. Interestingly, the acetylalkylglycerol acetylhydrolase was down-expressed in transgenic lines, which caused 19 lyso-phosphatidylcholine and derivatives of lipids to be up-accumulated, and 8 octodecane and derivatives were down-accumulated. This research will give more information about the function of MYB transcription factors on the anthocyanin biosynthesis and other chemical compounds and be of benefit to obtaining new plant cultivars with high anthocyanin content by biotechnology.

scholarly journals Comprehensive influences of overexpression of a MYB transcriptor regulating anthocyanin biosynthesis on transcriptome and metabolome of tobacco leaves

2019 ◽  
Author(s):  
Yuan Zong ◽  
Shiming Li ◽  
Xingyuan Xi ◽  
Dong Cao ◽  
Zhong Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Anthocyanin Biosynthesis ◽  
Chemical Compounds ◽  
Myb Transcription Factor ◽  
Biosynthesis Pathway ◽  
Structural Genes ◽  
Leaf Phenotype ◽  
Transgenic Lines ◽  
Purple Leaf

Abstract Background Overexpression of MYB transcription factors can induce the expression of structural genes for anthocyanin biosynthesis and increase the anthocyanin content of plant tissues. However, it remains unclear whether MYB transcription factor overexpression effects the activation of other genes and the concomitant accumulation of chemical compounds. Results Overexpression of LrAN2 promoted anthocyanin accumulation in a variety of tissues in tobacco cultivar Samsun. Only 185 unigenes, from total of 160,965, were expressed differently in leaves and 241 chemical compounds exhibited differences in accumulation. Four anthocyanins, including apigeninidin chloride, cyanidin 3-O-malonylhexoside, pelargonidin 3-O-beta-D-glucoside, and cyanidin 3,5-O-diglucoside were detected only in transgenic lines, which could explain the purple leaf phenotype. Beside anthocyanins, the phenylpropanoids, polyphenols (catechins), flavonoids, flavones, and flavonols were also upregulated. Overexpression of LrAN2 activated the basic helix-loop-helix transcription factor AN1b, and the MYB transcription factor MYB3. Additionally, structural genes associated with the phenylpropanoid biosynthetic pathway were activated, which lead to the upregulated accumulation of phenylpropanoid, polyphenol (catechin), flavonoid, flavone, flavonol, and anthocyanin. The MYB transcription factor CPC, a negative regulator of anthocyanin biosynthesis, was also expressed at increased levels in transgenic lines, which implie that a negative regulation mechanism existed in the anthocyanin biosynthesis pathway. The relative contents of all 19 differently accumulated amino groups and derivatives were decreased in transgenic lines, which meant that the phenylalanine biosynthesis pathway used other amino acids as substrates. Interestingly, the expression of acetylalkylglycerol acetylhydrolase was suppressed in transgenic lines, which caused the accumulation of 19 lyso-phosphatidylcholine derivatives and a decrease in production of eight octodecane derivatives. Conclusions Overexpression of LrAN2 activates the pathway of anthocyanin synthesis and metabolism in tobacco. Four anthocyanins lead to the purple leaf phenotype The main pathways of flavonoid biosynthesis were up-regulated. This research provides more information about the function of MYB transcription factors in anthocyanin biosynthesis and the production of other chemical compounds. This work will help breeders to obtain new plant cultivars with high anthocyanin contents using biotechnology.

scholarly journals Article Functional MYB transcription factor gene HtMYB2 is associated with anthocyanin biosynthesis in Helianthus tuberosus L.

2020 ◽  
Author(s):  
Jieming Gao ◽  
Xuemei Sun ◽  
Yuan Zong ◽  
Shipeng Yang ◽  
Lihui Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Promoter Region ◽  
Anthocyanin Biosynthesis ◽  
Jerusalem Artichoke ◽  
Myb Transcription Factor ◽  
Anthocyanin Content ◽  
Helianthus Tuberosus ◽  
Biosynthesis Pathway ◽  
Tuber Skin ◽  
Indel Mutation

Abstract Background: Tuber color is an important trait for Helianthus tuberosus L. (Jerusalem artichoke). Usually, purple tubers with high anthocyanin content are more nutritious than white tuber. But, the molecular mechanism underlying it is unknown. Results: In the current study, high-throughput RNA-sequencing was used to compare the transcriptomes between plants with tubers with red or white epidermis. Anthocyanin biosynthesis structural genes had greater expression in the red-skinned tubers of cultivar QY1, indicating that the anthocyanin biosynthesis pathway was activated in ‘QY1’; quantitative PCR confirmed this difference in expression. HtMYB2 (Unigene44371_All) was the only MYB transcription factor, homologous to the MYB transcription factor regulating anthocyanin biosynthesis, expressed in the red tuber epidermis of ‘QY1’. The anthocyanin concentration in the root, stem, leaf, flower, and tuber epidermis of ‘QY1’ was higher than in ‘QY3’, especially tuber epidermis. Correspondingly, HtMYB2 had greater expression in these tissues of ‘QY1’ than in ‘QY3’. The expression of HtMYB2 was associated with anthocyanin accumulation in the different tissues. Overexpression of HtMYB2 activated the anthocyanin biosynthesis pathway, accumulating the pigment in leaves of transgenic tobacco, supporting the model that HtMYB2 regulated anthocyanin biosynthesis. Further experiments found that HtMYB2 had the same coding sequence and genomic sequence in ‘QY1’ and ‘QY3’, but that there were several single nucleotide polymorphisms and one insertion–deletion (indel) mutation of 21 nucleotides in the promoter region between the two alleles. The deletion of three nucleotides “AAA” made the promoter of ‘QY1’ predicted to contain one more possible promoter region. A specific primer, based on the indel, could differentiate between cultivars with red or white tuber epidermis. The genetic variation in HtMYB2 was associated with the tuber skin color in a natural population. Conclusions: RNA-seq can successfully isolate the candidate gene ( HTMYB2 ) controlling anthocyanin biosynthesis in purple epidermis of Jerusalem artichoke tuber. HTMYB2 can regulate anthocyanin biosynthesis in plants and is closely related to the formation of purple phenotype in tubers. This study should be useful in understanding the genetic mechanism underlying different tuber skin colors and in breeding new H. tuberosus cultivars with different tuber skin colors.

scholarly journals Article Functional MYB transcription factor gene HtMYB2 is associated with anthocyanin biosynthesis in Helianthus tuberosus L.

2020 ◽  
Author(s):  
Jieming Gao ◽  
Xuemei Sun ◽  
Yuan Zong ◽  
Shipeng Yang ◽  
Lihui Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Promoter Region ◽  
Anthocyanin Biosynthesis ◽  
Jerusalem Artichoke ◽  
Myb Transcription Factor ◽  
Anthocyanin Content ◽  
Helianthus Tuberosus ◽  
Biosynthesis Pathway ◽  
Tuber Skin ◽  
Indel Mutation

Abstract Background: Tuber color is an important trait for Helianthus tuberosus L. (Jerusalem artichoke). Usually, purple tubers with high anthocyanin content are more nutritious than white tuber. But, the molecular mechanism underlying it is unknown. Results: In the current study, high-throughput RNA-sequencing was used to compare the transcriptomes between plants with tubers with red or white epidermis. Compared with the white-skinned tubers of cultivar QY3, anthocyanin biosynthesis structural genes had greater expression in the red-skinned tubers of cultivar QY1, indicating that the anthocyanin biosynthesis pathway was activated in ‘QY1’; quantitative PCR confirmed this difference in expression. HtMYB2 (Unigene44371_All) was the only MYB transcription factor，homologous to the MYB transcription factor regulating anthocyanin biosynthesis, expressed in the red tuber epidermis of ‘QY1’. The anthocyanin concentration in the root, stem, leaf, flower, and tuber epidermis of ‘QY1’ was higher than in ‘QY3’, especially tuber epidermis. Correspondingly, HtMYB2 had greater expression in these tissues of ‘QY1’ than in ‘QY3’. The expression of HtMYB2 was associated with anthocyanin accumulation in the different tissues. Overexpression of HtMYB2 activated the anthocyanin biosynthesis pathway, accumulating the pigment in leaves of transgenic tobacco, supporting the model that HtMYB2 regulated anthocyanin biosynthesis. Further experiments found that HtMYB2 had the same coding sequence and genomic sequence in ‘QY1’ and ‘QY3’, but that there were several single nucleotide polymorphisms and one insertion–deletion (indel) mutation of 21 nucleotides in the promoter region between the two alleles. The deletion of three nucleotides “AAA” made the promoter of ‘QY1’ predicted to contain one more possible promoter region. A specific primer, based on the indel, could differentiate between cultivars with red or white tuber epidermis. The genetic variation in HtMYB2 was associated with the tuber skin color in a natural population.Conclusions: RNA-seq can successfully isolate the candidate gene (HTMYB2) controlling anthocyanin biosynthesis in purple epidermis of Jerusalem artichoke tuber. HTMYB2 can regulate anthocyanin biosynthesis in plants and is closely related to the formation of purple phenotype in tubers. This study should be useful in understanding the genetic mechanism underlying different tuber skin colors and in breeding new H. tuberosus cultivars with different tuber skin colors.

scholarly journals Article Functional MYB transcription factor gene HtMYB2 is associated with anthocyanin biosynthesis in Helianthus tuberosus L.

2020 ◽  
Author(s):  
Jieming Gao ◽  
Xuemei Sun ◽  
Yuan Zong ◽  
Shipeng Yang ◽  
Lihui Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Promoter Region ◽  
Anthocyanin Biosynthesis ◽  
Jerusalem Artichoke ◽  
Myb Transcription Factor ◽  
Anthocyanin Content ◽  
Helianthus Tuberosus ◽  
Biosynthesis Pathway ◽  
Tuber Skin ◽  
Indel Mutation

Abstract Background: Tuber color is an important trait for Helianthus tuberosus L. (Jerusalem artichoke). Usually, purple tubers with high anthocyanin content are more nutritious than white tuber. But, the molecular mechanism underlying it is unknown. Results: In the current study, high-throughput RNA-sequencing was used to compare the transcriptomes between plants with tubers with red or white epidermis. Anthocyanin biosynthesis structural genes had greater expression in the red-skinned tubers of cultivar QY1, indicating that the anthocyanin biosynthesis pathway was activated in ‘QY1’; quantitative PCR confirmed this difference in expression. HtMYB2 (Unigene44371_All) was the only MYB transcription factor, homologous to the MYB transcription factor regulating anthocyanin biosynthesis, expressed in the red tuber epidermis of ‘QY1’. The anthocyanin concentration in the root, stem, leaf, flower, and tuber epidermis of ‘QY1’ was higher than in ‘QY3’, especially tuber epidermis. Correspondingly, HtMYB2 had greater expression in these tissues of ‘QY1’ than in ‘QY3’. The expression of HtMYB2 was associated with anthocyanin accumulation in the different tissues. Overexpression of HtMYB2 activated the anthocyanin biosynthesis pathway, accumulating the pigment in leaves of transgenic tobacco, supporting the model that HtMYB2 regulated anthocyanin biosynthesis. Further experiments found that HtMYB2 had the same coding sequence and genomic sequence in ‘QY1’ and ‘QY3’, but that there were several single nucleotide polymorphisms and one insertion–deletion (indel) mutation of 21 nucleotides in the promoter region between the two alleles. The deletion of three nucleotides “AAA” made the promoter of ‘QY1’ predicted to contain one more possible promoter region. A specific primer, based on the indel, could differentiate between cultivars with red or white tuber epidermis. The genetic variation in HtMYB2 was associated with the tuber skin color in a natural population. Conclusions: RNA-seq can successfully isolate the candidate gene ( HTMYB2 ) controlling anthocyanin biosynthesis in purple epidermis of Jerusalem artichoke tuber. HTMYB2 can regulate anthocyanin biosynthesis in plants and is closely related to the formation of purple phenotype in tubers. This study should be useful in understanding the genetic mechanism underlying different tuber skin colors and in breeding new H. tuberosus cultivars with different tuber skin colors.

scholarly journals Functional MYB transcription factor gene HtMYB2 is associated with anthocyanin biosynthesis in Helianthus tuberosus L.

2020 ◽  
Author(s):  
Jieming Gao ◽  
Yuan Zong ◽  
Shipeng Yang ◽  
Lihui Wang ◽  
Baolong Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Promoter Region ◽  
Genomic Sequence ◽  
Anthocyanin Biosynthesis ◽  
Jerusalem Artichoke ◽  
Myb Transcription Factor ◽  
Helianthus Tuberosus ◽  
Biosynthesis Pathway ◽  
Tuber Skin ◽  
Indel Mutation

Abstract Background: Tuber color is an important trait for Helianthus tuberosus L. (Jerusalem artichoke), but the molecular mechanism underlying it is unknown. Results: In the current study, high-throughput RNA-sequencing was used to compare the transcriptomes between plants with tubers with red or white epidermis. Compared with the white-skinned tubers of cultivar QY3, anthocyanin biosynthesis structural genes had greater expression in the red-skinned tubers of cultivar QY1, indicating that the anthocyanin biosynthesis pathway was activated in ‘QY1’; quantitative PCR confirmed this difference in expression. HtMYB2 (Unigene44371_All) was the only MYB transcription factor expressed in the red tuber epidermis of ‘QY1’. HtMYB2 resembled an MYB transcription factor, regulating anthocyanin biosynthesis, and possessing an intact SANT/MYB and MYB-like DNA-binding domain. The anthocyanin concentration in the root, stem, leaf, flower, and tuber epidermis of ‘QY1’ was higher than in ‘QY3’, especially tuber epidermis. Correspondingly, HtMYB2 had greater expression in these tissues of ‘QY1’ than in ‘QY3’. The expression of HtMYB2 was associated with anthocyanin accumulation in the different tissues. Overexpression of HtMYB2 activated the anthocyanin biosynthesis pathway, accumulating the pigment in leaves of transgenic tobacco, supporting the model that HtMYB2 regulated anthocyanin biosynthesis. Further experiments found that HtMYB2 had the same coding sequence and genomic sequence in ‘QY1’ and ‘QY3’, but that there were several single nucleotide polymorphisms and one insertion–deletion (indel) mutation of 21 nucleotides in the promoter region between the two alleles. The deletion of three nucleotides “AAA” made the promoter of ‘QY1’ predicted to contain one more possible promoter region. A specific primer, based on the indel, could differentiate between cultivars with red or white tuber epidermis. The genetic variation in HtMYB2 was associated with the tuber skin color in a natural population.Conclusions: RNA-seq can successfully isolate the candidate gene (HTMYB2) controlling anthocyanin biosynthesis in purple epidermis of Jerusalem artichoke tuber. HTMYB2 can regulate anthocyanin biosynthesis in plants and is closely related to the formation of purple phenotype in tubers. This study should be useful in understanding the genetic mechanism underlying different tuber skin colors and in breeding new H. tuberosus cultivars with different tuber skin colors.

scholarly journals CmMYB#7, an R3 MYB transcription factor, acts as a negative regulator of anthocyanin biosynthesis in chrysanthemum

2019 ◽  
Vol 70 (12) ◽  
pp. 3111-3123 ◽  
Author(s):  
Lili Xiang ◽  
Xiaofen Liu ◽  
Heng Li ◽  
Xueren Yin ◽  
Donald Grierson ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Binding Site ◽  
Transient Expression ◽  
Regulatory Mechanism ◽  
Anthocyanin Biosynthesis ◽  
Expression Patterns ◽  
Negative Regulator ◽  
Myb Transcription Factor ◽  
Anthocyanin Content

Abstract ‘Jimba’, a well-known white flowered chrysanthemum cultivar, occasionally and spontaneously produces red colored petals under natural cultivation, but there is little information about the molecular regulatory mechanism underlying this process. We analysed the expression patterns of 91 MYB transcription factors in ‘Jimba’ and ‘Turning red Jimba’ and identified an R3 MYB, CmMYB#7, whose expression was significantly decreased in ‘Turning red Jimba’ compared with ‘Jimba’, and confirmed it is a passive repressor of anthocyanin biosynthesis. CmMYB#7 competed with CmMYB6, which together with CmbHLH2 is an essential component of the anthocyanin activation complex, for interaction with CmbHLH2 through the bHLH binding site in the R3 MYB domain. This reduced binding of the CmMYB6–CmbHLH2 complex and inhibited its ability to activate CmDFR and CmUFGT promoters. Moreover, using transient expression assays we demonstrated that changes in the expression of CmMYB#7 accounted for alterations in anthocyanin content. Taken together, our findings illustrate that CmMYB#7 is a negative regulator of anthocyanin biosynthesis in chrysanthemum.

scholarly journals Overexpression of ThMYC4E Enhances Anthocyanin Biosynthesis in Common Wheat

2019 ◽  
Vol 21 (1) ◽  
pp. 137 ◽  
Author(s):  
Shuo Zhao ◽  
Xingyuan Xi ◽  
Yuan Zong ◽  
Shiming Li ◽  
Yun Li ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Common Wheat ◽  
Anthocyanin Biosynthesis ◽  
Pcr Analysis ◽  
Bhlh Transcription Factor ◽  
Anthocyanin Content ◽  
Metabolome Analysis ◽  
Helix Loop Helix ◽  
Transgenic Lines ◽  
Ethanol Extracts

The basic helix-loop helix (bHLH) transcription factor has been inferred to play an important role in blue and purple grain traits in common wheat, but to date, its overexpression has not been reported. In this study, the bHLH transcription factor ThMYC4E, the candidate gene controlling the blue grain trait from Th. Ponticum, was transferred to the common wheat JW1. The positive transgenic lines displayed higher levels of purple anthocyanin pigments in their grains, leaves and glumes. Stripping the glumes (light treatment) caused white grains to become purple in transgenic lines. RNA-Seq and qRT-PCR analysis demonstrated that the transcript levels of structural genes associated with anthocyanin biosynthesis were higher in transgenic wheat than the wild-type (WT), which indicated that ThMYC4E activated anthocyanin biosynthesis in the transgenic lines. Correspondingly, the anthocyanin contents in grains, roots, stems, leaves and glumes of transgenic lines were higher than those in the WT. Metabolome analysis demonstrated that the anthocyanins were composed of cyanidin and delphinidin in the grains of the transgenic lines. Moreover, the transgenic lines showed higher antioxidant activity, in terms of scavenging DPPH radicals, in the ethanol extracts of their grains. The overexpression of ThMYC4E sheds light on the traits related to anthocyanin biosynthesis in common wheat and provide a new way to improve anthocyanin content.

Functional R2R3-MYB Transcription Factor NsMYB1, Regulating Anthocyanin Biosynthesis, Was Relative To The Fruit Color Differentiation in Nitraria Sibirica Pall

2021 ◽  
Author(s):  
Xuemei Bao ◽  
Yuan Zong ◽  
Na Hu ◽  
Shiming Li ◽  
Baolong Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Chemical Analysis ◽  
Anthocyanin Biosynthesis ◽  
Fruit Color ◽  
Tibet Plateau ◽  
Myb Transcription Factor ◽  
Structural Genes ◽  
Transcript Factor ◽  
Nitraria Sibirica ◽  
R2r3 Myb

Abstract Background Nitraria sibirica Pall. is an economic plant with two kinds of fruit color, widely spreads in the Qinghai Tibet Plateau. The chemical analysis and pharmacological evaluation had been carried out for several tens of years, the mechanism behind the fruit color differentiation is still unclear. Results In this manuscript, the chemical analysis of the extractions showed that the chemical composition of fruit color was anthocyanin, and two kind of Nitraria sibirica Pall. were caused by the content differentiation with the same anthocyanin kinds. Cya-nidin-3-[2ʹ’-(6ʹ’’-coumaroyl)-glucosyl]-glucoside (C3G) was the major anthocyanin. Transcriptome analysis and the qRT-PCR revealed that the structural genes relative to anthocyanin biosynthesis except CHS, F3’5’H and ANS were up-regulated in BF compared with RF, which indicated that transcript factor should be the reason for the expression difference of the structure genes. In the unigenes of the transcript factor MYB and bHLH, relative to anthocyanin, only NsMYB1 (Clus-ter-8422.10600), was high-expression and up-expression in the BF. NsMYB1 encoded the same length protein with four amino acid differences in the RF and BF, and both contained the intact DNA, HTH-MYB and SANT domains. NsMYB1 was close to the AtMYB114, AtMYB113 and AtPAP1, regulating anthocyanin biosynthesis, in phylogenetic relationship. Both NsMYB1r and NsMYB1b could promote the transcript of the structural genes, and induced the anthocyanin accumulation in all tissues of transgenic tobacco. The insertion of ‘TATA’ in the promoter of NsMYB1r gave one more promoter region, and was the reason for higher transcripts in black fruit possibly. Conclusions NsMYB1 was a functional R2R3-MYB transcription factor, regulated the anthocyanin biosynthesis, and leaded to the fruit color differentiation in Nitraria sibirica Pall.

scholarly journals A Novel R2R3-MYB Transcription Factor PqMYB4 Inhibited Anthocyanin Biosynthesis in Paeonia qiui

2020 ◽  
Vol 21 (16) ◽  
pp. 5878
Author(s):  
Dan Huo ◽  
Xiaokun Liu ◽  
Yue Zhang ◽  
Jingjing Duan ◽  
Yanlong Zhang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Coat Color ◽  
Anthocyanin Biosynthesis ◽  
Myb Transcription Factor ◽  
Anthocyanin Content ◽  
Wild Type ◽  
Tree Peony ◽  
Anthocyanin Pathway ◽  
Red Color ◽  
R2r3 Myb

Paeonia qiui is a wild tree peony native to China. Its leaves show a clear purple-red color from the germination to the flowering stage, and it has high leaf-viewing value. A MYB transcription factor gene, designated as PqMYB4, was isolated from leaves of P. qiui based on transcriptome datas. The full-length cDNA of PqMYB4 was 693 bp, encoding 230 amino acids. Sequence alignment and phylogenetic analysis revealed that PqMYB4 was a R2R3-MYB transcription factor clustered with AtMYB4 in Arabidopsis thaliana. Moreover, it contained a C1 motif, an EAR repression motif and a TLLLFR motif in the C-terminal domains, which were unique in transcription repression MYB. Subcellular location analysis showed that PqMYB4 was located in the cell nucleus. PqMYB4 was highly expressed in the late stage of leaf development, and was negatively correlated with the anthocyanin content. The petiole of wild-type Arabidopsis seedlings was deeper in color than the transgenic lines of PqMYB4 and showed a little purple-red color. The seed coat color of Arabidopsis seeds that overexpressed PqMYB4 gene was significantly lighter than that of wild-type seeds. In transgenic Arabidopsis, the expression level of AtCHS, AtCHI, AtDFR and AtANS were down-regulated significantly. These results showed that PqMYB4 was involved in the negative regulation of anthocyanin biosynthesis in tree peony leaves, which can control the anthocyanin pathway genes. Together, these findings provide a valuable resource with which to further study the regulatory mechanism of anthocyanin biosynthesis in the leaf of P. qiui. They also benefit the molecular breeding of tree peony cultivars with colored leaf.

scholarly journals The R2R3-type MYB transcription factor MdMYB90-like is responsible for the enhanced skin color of an apple bud sport mutant

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Chao Sun ◽  
Chunming Wang ◽  
Wang Zhang ◽  
Shuai Liu ◽  
Weiyao Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Skin Color ◽  
Anthocyanin Biosynthesis ◽  
Regulatory Gene ◽  
Gene Promoter ◽  
Luciferase Assay ◽  
Myb Transcription Factor ◽  
Anthocyanin Content ◽  
Mobility Shift ◽  
Mobility Shift Assay

AbstractThe anthocyanin content in apple skin determines its red coloration, as seen in a Fuji apple mutant. Comparative RNA-seq analysis was performed to determine differentially expressed genes at different fruit development stages between the wild-type and the skin color mutant. A novel R2R3-MYB transcription factor, MdMYB90-like, was uncovered as the key regulatory gene for enhanced coloration in the mutant. The expression of MdMYB90-like was 21.3 times higher in the mutant. MdMYB90-like regulates anthocyanin biosynthesis directly through the activation of anthocyanin biosynthesis genes and indirectly through the activation of other transcription factors that activate anthocyanin biosynthesis. MdMYB90-like bound to the promoters of both structural genes (MdCHS and MdUFGT) and other transcription factor genes (MdMYB1 and MdbHLH3) in the yeast one-hybrid system, electrophoretic mobility shift assay, and dual-luciferase assay. Transgenic analysis showed that MdMYB90-like was localized in the nucleus, and its overexpression induced the expression of other anthocyanin-related genes, including MdCHS, MdCHI, MdANS, MdUFGT, MdbHLH3, and MdMYB1. The mutant had reduced levels of DNA methylation in two regions (−1183 to −988 and −2018 to −1778) of the MdMYB90-like gene promoter, which might explain the enhanced expression of the gene and the increased anthocyanin content in the mutant apple skin.

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