Arabidopsis CAPRICE (MYB) and GLABRA3 (bHLH) control tomato (Solanum lycopersicum) anthocyanin biosynthesis.

Takuji Wada,Rumi Tominaga-Wada,Asuka Kunihiro,Takaya Moriguchi

doi:10.1371/journal.pone.0109093

Abstract

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.

Highlights

Anthocyanins are important chemical compound of polyphenolic pigments derived from the phenylpropanoid biosynthetic pathway
We showed that anthocyanin accumulation was repressed in the CPC::Solanum lycopersicum TRYPTICHON (SlTRY) and GL3::Solanum lycopersicum GLABRA3 (SlGL3) transgenic Arabidopsis plants, suggesting that the tomato genes of SlTRY and SlGL3 are involved in anthocyanin biosynthesis [34]
To establish whether Arabidopsis CPC and GL3 transcription factors function in tomato, we introduced these genes into one of tomato cultivars

Summary

Introduction

Anthocyanins are important chemical compound of polyphenolic pigments derived from the phenylpropanoid biosynthetic pathway. Anthocyanins belong to the group of flavonoids, of which they are noticeable in the wide range of chemical structures [1]. Anthocyanins provide appealing color to leaves, flowers, fruits and seeds in plants. In addition to this obvious feature, they have other essential functions. Anthocyanin synthesis was induced by the stressful occasions, such as low temperature or strong irradiation of the sunlight, against which they protect the plant as scavengers for radical species or a light-screen [2]. Anthocyanins are produced through several enzymatic step [3]. The enzymes which are involved in anthocyanin synthesis are fully analyzed by both biochemical and genetic approaches

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Conclusion