Characterization and functional analysis of a MYB gene (GbMYBFL) related to flavonoid accumulation in Ginkgo biloba

Abstract

Flavonoids are a group of metabolites in Ginkgo biloba thought to provide health benefits. R2R3-MYB transcription factors (TFs) play key roles in the transcriptional regulation of the flavonoid biosynthesis in plants. In this study, an R2R3-MYB transcription factor gene, GbMYBFL, was isolated from G. biloba and characterized. Results of bioinformatic analysis indicated that GbMYBFL is more closely related to the R2R3-MYB involved in flavonoid biosynthesis and displayed high similarity to MYB from other plants. The genmomic sequence of GbMYBFL had three exons and two introns, with its upstream sequence containing cis-acting regulatory elements Myb binding site, Myc recognition sites, and light, SA, MeJA responsive elements. Subcellular localization analysis indicates that GbMYBFL was located in the nucleus. Quantitative real-time PCR revealed that GbMYBFL was expressed in leaves, stems, roots, young fruits, male flower and female flower, and the level of transcription in male flower and leaves were higher than that in female flower, stems, roots, and young fruits. During G. biloba leaf growth, the transcription of GbMYBFL is positively correlated with the flavonoid content, suggesting that the GbMYBFL is involved in the flavonoid biosynthesis. Overexpression of GbMYBFL under the control of the CaMV35S promoter in Ginkgo callus notably enhanced the accumulation of flavonoids and anthocyanin compared with non-transformed callus. This finding suggested that GbMYBFL positively related to flavonoid biosynthesis, and the overexpression of GbMYBFL was sufficient to induce flavonoids and anthocyanin accumulation.

Genome-wide identification and characterization of bHLH family genes from Ginkgo biloba

“…For example, our previous work demonstrated that an R2R3-MYB gene GbMYBF2 act as negative regulators of flavonoids biosynthesis in G. biloba 53 . More recently, Zhang et al 54 stated that another MYB gene GbMYBFL played a positive role on flavonoids biosynthesis in G. biloba . To date, some bHLH proteins was found to play important role in the regulation of flavonoids biosynthesis.…”

PgMYB2, a MeJA-Responsive Transcription Factor, Positively Regulates the Dammarenediol Synthase Gene Expression in Panax Ginseng

“…In land plants, R2R3-MYB is the most abundant among these groups and is widely involved in various aspects of plant physiological metabolism [16]. In the past few years, many MYB genes have been shown to be involved in the response of different plant hormones such as ABA, SA, and MeJA, which related to plant defense and secondary metabolism [17,18,19]. In Nicotiana tabacum , NtMYBJS1 regulates the production of phenylpropanoid in a MeJA-dependent manner [20], whereas NtMYB1 and NtMYB2 are regulated by SA and are involved in plant defense [21].…”

GbMYBR1 from Ginkgo biloba represses phenylpropanoid biosynthesis and trichome development in Arabidopsis

“…Ginkgo leaf extracts display multiple pharmaceutical functions (e.g., radical scavenging and antioxidant activities, anti-inflammation activity, and neuroprotective activity); therefore, Ginkgo has been utilized and investigated for centuries, leading to the identification of more than 60 different types of flavonoid compounds (van Beek and Montoro 2009 ; Liu et al 2015b ). Several genes associated with flavonoid biosynthesis have been identified and/or characterized in Ginkgo (Pang et al 2005 ; Shen et al 2006a , 2006b ; Cheng et al 2011 ; Hua et al 2013; Xu et al 2014a ; Su et al 2017 ; Zhang et al 2018 ). Although a few R2R3-type MYB genes were identified via sequence analysis and two MYB genes were found to be related to flavonoid regulation (Xu et al 2014a ; Zhang et al 2018 ), the regulatory mechanism of the flavonoid pathway by MYBs in Ginkgo remains unknown.…”

“…Several genes associated with flavonoid biosynthesis have been identified and/or characterized in Ginkgo (Pang et al 2005 ; Shen et al 2006a , 2006b ; Cheng et al 2011 ; Hua et al 2013; Xu et al 2014a ; Su et al 2017 ; Zhang et al 2018 ). Although a few R2R3-type MYB genes were identified via sequence analysis and two MYB genes were found to be related to flavonoid regulation (Xu et al 2014a ; Zhang et al 2018 ), the regulatory mechanism of the flavonoid pathway by MYBs in Ginkgo remains unknown.…”