Dataset Information

Ectopic Overexpression of a Novel R2R3-MYB, NtMYB2 from Chinese Narcissus Represses Anthocyanin Biosynthesis in Tobacco.

ABSTRACT: R2R3 MYB transcription factors play key functions in the regulation of secondary metabolites. In the present study, a R2R3 MYB transcriptional factor NtMYB2 was identified from Chinese narcissus (Narcissus tazetta L. var. Chinensis Roem) and functionally characterized. NtMYB2 belongs to subgroup 4 of the R2R3 MYB transcription factor family that are related to repressor MYBs involved in the regulation of anthocyanin and flavonoids. Transient expression confirmed that NtMYB2 strongly reduced the red pigmentation induced by MYB- anthocyanin activators in agro-infiltrated tobacco leaves. Ectopic expression of NtMYB2 in tobacco significantly reduced the pigmentation and altered the floral phenotypes in transgenic tobacco flowers. Gene expression analysis suggested that NtMYB2 repressed the transcript levels of structural genes involved in anthocyanin biosynthesis pathway, especially the UFGT gene. NtMYB2 gene is expressed in all examined narcissus tissues; the levels of transcription in petals and corona is higher than other tissues and the transcription level at the bud stage was highest. These results show that NtMYB2 is involved in the regulation of anthocyanin biosynthesis pathway and may act as a repressor by down regulating the transcripts of key enzyme genes in Chinese narcissus.

SUBMITTER: Anwar M

PROVIDER: S-EPMC6017421 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Ectopic Overexpression of a Novel R2R3-MYB, NtMYB2 from Chinese Narcissus Represses Anthocyanin Biosynthesis in Tobacco.

Anwar Muhammad M Wang Guiqing G Wu Jiacheng J Waheed Saquib S Allan Andrew C AC Zeng Lihui L

Molecules (Basel, Switzerland) 20180328 4

R2R3 MYB transcription factors play key functions in the regulation of secondary metabolites. In the present study, a R2R3 MYB transcriptional factor NtMYB2 was identified from Chinese narcissus (Narcissus tazetta L. var. Chinensis Roem) and functionally characterized. NtMYB2 belongs to subgroup 4 of the R2R3 MYB transcription factor family that are related to repressor MYBs involved in the regulation of anthocyanin and flavonoids. Transient expression confirmed that ...[more]

PMID: 29597321

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Project description: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.

Project description:BackgroundChinese cherry [Cerasus pseudocerasus (Lindl.) G.Don] (syn. Prunus pseudocerasus Lindl.) is an economically important fruiting cherry species with a diverse range of attractive colors, spanning from the lightest yellow to the darkest black purple. However, the MYB transcription factors involved in anthocyanin biosynthesis underlying fruit color variation in Chinese cherry remain unknown.ResultsIn this study, we characterized the R2R3-MYB gene family of Chinese cherry by genome-wide identification and compared it with those of 10 Rosaceae relatives and Arabidopsis thaliana. A total of 1490 R2R3-MYBs were classified into 43 subfamilies, which included 29 subfamilies containing both Rosaceae MYBs and AtMYBs. One subfamily (S45) contained only Rosaceae MYBs, while three subfamilies (S12, S75, and S77) contained only AtMYBs. The variation in gene numbers within identical subfamilies among different species and the absence of certain subfamilies in some species indicated the species-specific expansion within MYB gene family in Chinese cherry and its relatives. Segmental and tandem duplication events primarily contributed to the expansion of Chinese cherry R2R3-CpMYBs. The duplicated gene pairs underwent purifying selection during evolution after duplication events. Phylogenetic relationships and transcript profiling revealed that CpMYB10 and CpMYB4 are involved in the regulation of anthocyanin biosynthesis in Chinese cherry fruits. Expression patterns, transient overexpression and VIGS results confirmed that CpMYB10 promotes anthocyanin accumulation in the fruit skin, while CpMYB4 acts as a repressor, inhibiting anthocyanin biosynthesis of Chinese cherry.ConclusionsThis study provides a comprehensive and systematic analysis of R2R3-MYB gene family in Chinese cherry and Rosaceae relatives, and identifies two regulators, CpMYB10 and CpMYB4, involved in anthocyanin biosynthesis in Chinese cherry. These results help to develop and utilize the potential functions of anthocyanins in Chinese cherry.

Dataset Information

Ectopic Overexpression of a Novel R2R3-MYB, NtMYB2 from Chinese Narcissus Represses Anthocyanin Biosynthesis in Tobacco.

Publications

Ectopic Overexpression of a Novel R2R3-MYB, NtMYB2 from Chinese Narcissus Represses Anthocyanin Biosynthesis in Tobacco.

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