Identification of Two Novel R2R3-MYB Transcription factors, PsMYB114L and PsMYB12L, Related to Anthocyanin Biosynthesis in Paeonia suffruticosa

Abstract

Flower color is a charming phenotype with very important ornamental and commercial values. Anthocyanins play a critical role in determining flower color pattern formation, and their biosynthesis is typically regulated by R2R3-MYB transcription factors (TFs). Paeonia suffruticosa is a famous ornamental plant with colorful flowers. However, little is known about the R2R3-MYB TFs that regulate anthocyanin accumulation in P. suffruticosa. In the present study, two R2R3-MYB TFs, namely, PsMYB114L and PsMYB12L, were isolated from the petals of P. suffruticosa ‘Shima Nishiki’ and functionally characterized. Sequence analysis suggested that PsMYB114L contained a bHLH-interaction motif, whereas PsMYB12L contained two flavonol-specific motifs (SG7 and SG7-2). Subsequently, the in vivo function of PsMYB114L and PsMYB12L was investigated by their heterologous expression in Arabidopsis thaliana and apple calli. In transgenic Arabidopsis plants, overexpression of PsMYB114L and of PsMYB12L caused a significantly higher accumulation of anthocyanins, resulting in purple-red leaves. Transgenic apple calli overexpressing PsMYB114L and PsMYB12L also significantly enhanced the anthocyanins content and resulted in a change in the callus color to red. Meanwhile, gene expression analysis in A. thaliana and apple calli suggested that the expression levels of the flavonol synthase (MdFLS) and anthocyanidin reductase (MdANR) genes were significantly downregulated and the dihydroflavonol 4-reductase (AtDFR) and anthocyanin synthase (AtANS) genes were significantly upregulated in transgenic lines of PsMYB114L. Moreover, the expression level of the FLS gene (MdFLS) was significantly downregulated and the DFR (AtDFR/MdDFR) and ANS (AtANS/MdANS) genes were all significantly upregulated in transgenic lines plants of PsMYB12L. These results indicate that PsMYB114L and PsMYB12L both enhance anthocyanin accumulation by specifically regulating the expression of some anthocyanin biosynthesis-related genes in different plant species. Together, these results provide a valuable resource with which to further study the regulatory mechanism of anthocyanin biosynthesis in P. suffruticosa and for the breeding of tree peony cultivars with novel and charming flower colors.

The novel gene BrMYB2, located on chromosome A07, with a short intron 1 controls the purple-head trait of Chinese cabbage (Brassica rapa L.)

“…Recent studies of purple head Chinese cabbage revealed that total anthocyanin content is associated with high expression of only BrMYB2 (Bra004162) among these three BrMYBs, accompanied by upregulation of BrTT8 and a series of ABGs, including BrF3'H, BrDFR, BrANS, BrUGTs, and BrGSTs 10,27 . Recent advances have shown that MYBs activate bHLHs and ABGs through strong interactions with bHLHs to promote anthocyanin biosynthesis in crop plants [38][39][40] . In purple cauliflower and red cabbage, BoMYB2 is responsible for the purple trait by interacting with BoHLHs and related ABGs [15][16][17] , and homologous comparisons showed that BrMYB2 is highly homologous with BoMYB2 (Fig.…”

Integrated metabolic profiling and transcriptome analysis of pigment accumulation in diverse petal tissues in the lily cultivar ‘Vivian’

“…For example, conical epidermal cells contained significantly more anthocyanin and other flavonoids than flat epidermal cells in Antirrhinum petals [51]. In transgenic Arabidopsis plants, overexpression of PsMYB114L and of PsMYB12L caused a significantly higher accumulation of anthocyanins, resulting in purple-red leaves [52]. In Phalaenopsis orchids, PeMYB11-silencing resulted in the loss of anthocyanin content with flower colors fading from darkpurple to pink [2].…”

Isolation and Analysis of Anthocyanin Pathway Genes from Ribes Genus Reveals MYB Gene with Potent Anthocyanin-Inducing Capabilities

“…However, anthocyanin content in Paeonia flowers differs significantly from that of Ribes fruits, with peonidin, pelargonidin and cyanidin 3- and 3,5-glucosides being the main species in Paeonia [ 20 ]. Although anthocyanin-regulating MYBs and, to a lesser degree, the other regulators have been analyzed in many plants, such genes in Saxifragales were only recently identified in P. suffruticosa [ 21 , 22 , 23 ].…”