The Onion (Allium cepa L.) R2R3-MYB Gene MYB1 Regulates Anthocyanin Biosynthesis

AbstractAnthocyanins are the largest group of water-soluble pigments and beneficial for human health. Although most plants roots have the potential to express natural biosynthesis pathways required to produce specialized metabolites such as anthocyanins, the anthocyanin synthesis is specifically silenced in roots. To explore the molecular mechanism of absence and production ability of anthocyanin in the roots, investigated the effect of a bHLH gene AmDelila, and an R2R3-MYB gene AmRosea1, which are the master regulators of anthocyanin biosynthesis in Antirrhinum majus flowers, by expressing these genes in transformed hairy roots of A. majus. Co-ectopic expression of both AmDelila and AmRosea1 significantly upregulated the expression of the key target structural genes in the anthocyanin biosynthesis pathway. Furthermore, this resulted in strongly enhanced anthocyanin accumulation in transformed hairy roots. Ectopic expression of AmDelila alone did not gives rise to any significant anthocyanin accumulation, however, ectopic expression of AmRosea1 alone clearly upregulated expression of the main structural genes as well as greatly promoted anthocyanin accumulation in transformed hairy roots, where the contents reached 0.773–2.064 mg/g fresh weight. These results suggest that AmRosea1 plays a key role in the regulatory network in controlling the initiation of anthocyanin biosynthesis in roots, and the combination of AmRosea1 and hairy root culture is a powerful tool to study and production of anthocyanins in the roots of A. majus.

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Ethylene‐activated PpERF105 induces the expression of the repressor‐type R2R3‐MYB gene PpMYB140 to inhibit anthocyanin biosynthesis in red pear fruit

The Plant Journal ◽

10.1111/tpj.15049 ◽

2020 ◽

Author(s):

Junbei Ni ◽

Apekshika T. Premathilake ◽

Yuhao Gao ◽

Wenjie Yu ◽

Ruiyan Tao ◽

...

Keyword(s):

Anthocyanin Biosynthesis ◽

Pear Fruit ◽

Myb Gene ◽

R2r3 Myb

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The R2R3-MYB gene PsMYB58 positively regulates anthocyanin biosynthesis in tree peony flowers

Plant Physiology and Biochemistry ◽

10.1016/j.plaphy.2021.04.034 ◽

2021 ◽

Author(s):

Yanzhao Zhang ◽

Shuzhen Xu ◽

Huiping Ma ◽

Xujia Duan ◽

Shouxin Gao ◽

...

Keyword(s):

Anthocyanin Biosynthesis ◽

Tree Peony ◽

Myb Gene ◽

R2r3 Myb

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Genome-wide characterization of the R2R3-MYB transcription factors in pepper (Capsicum spp.) unveils the role of CaMYB101 as repressor in anthocyanin biosynthesis

10.1101/2021.08.24.457473 ◽

2021 ◽

Author(s):

Ying Liu ◽

Yi Wu ◽

Zicheng Wang ◽

Shiya Zhang ◽

Xintong Liu ◽

...

Keyword(s):

Anthocyanin Biosynthesis ◽

Virus Induced Gene Silencing ◽

Myb Gene ◽

Genome Wide ◽

A Genome ◽

Capsicum Spp ◽

Important Regulator ◽

R2r3 Myb

AbstractFruit colour is one of the most important commercial traits of pepper (Capsicum spp.), a major horticultural crop worldwide. Some pepper accessions temporarily accumulate anthocyanins during fruit development and gradually lose them upon fruit ripening. Meanwhile, anthocyanin biosynthesis gradually stops. However, how this process is exactly regulated is still largely unknown. R2R3-MYB is one of the largest plant transcription factor families, and it is considered the most important regulator for the biosynthesis of anthocyanins and other flavonoids. Although R2R3-MYBs are widely studied in many plants, research in pepper has been limited. In this study, we performed a genome-wide analysis of R2R3-MYBs across three cultivated pepper species (C. annuum, C. baccatum, and C. chinense ) involving identification, chromosome localization, gene structure analysis, phylogenetic analysis and collinearity analysis. Candidate R2R3-MYB repressors were further identified based on repression motifs. An R2R3-MYB gene, CaMYB101, was selected based on its high homology with anthocyanin biosynthesis repressors in tomato and petunia as well as its high expression level in fruit when purple pigmentation started to discolour. By using virus-induced gene silencing, CaMYB101 was characterized as an anthocyanin biosynthesis repressor. To our knowledge, CaMYB101 is the first transcriptional repressor associated with anthocyanin biosynthesis identified in pepper.

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