A Novel R2R3-MYB Transcription Factor PqMYB4 Inhibited Anthocyanin Biosynthesis in Paeonia qiui

Abstract

Paeonia qiui is a wild tree peony native to China. Its leaves show a clear purple-red color from the germination to the flowering stage, and it has high leaf-viewing value. A MYB transcription factor gene, designated as PqMYB4, was isolated from leaves of P. qiui based on transcriptome datas. The full-length cDNA of PqMYB4 was 693 bp, encoding 230 amino acids. Sequence alignment and phylogenetic analysis revealed that PqMYB4 was a R2R3-MYB transcription factor clustered with AtMYB4 in Arabidopsis thaliana. Moreover, it contained a C1 motif, an EAR repression motif and a TLLLFR motif in the C-terminal domains, which were unique in transcription repression MYB. Subcellular location analysis showed that PqMYB4 was located in the cell nucleus. PqMYB4 was highly expressed in the late stage of leaf development, and was negatively correlated with the anthocyanin content. The petiole of wild-type Arabidopsis seedlings was deeper in color than the transgenic lines of PqMYB4 and showed a little purple-red color. The seed coat color of Arabidopsis seeds that overexpressed PqMYB4 gene was significantly lighter than that of wild-type seeds. In transgenic Arabidopsis, the expression level of AtCHS, AtCHI, AtDFR and AtANS were down-regulated significantly. These results showed that PqMYB4 was involved in the negative regulation of anthocyanin biosynthesis in tree peony leaves, which can control the anthocyanin pathway genes. Together, these findings provide a valuable resource with which to further study the regulatory mechanism of anthocyanin biosynthesis in the leaf of P. qiui. They also benefit the molecular breeding of tree peony cultivars with colored leaf.

Regulation of BcMYB44 on Anthocyanin Synthesis and Drought Tolerance in Non-Heading Chinese Cabbage (Brassica campestris ssp. chinensis Makino)

“…As one of the largest TF families in higher plants, MYB TF involves diverse biological, functional and structural processes [28]. Several studies showed that flavonoid-related R2R3-MYB repressors had been isolated in various plants, such as PqMYB4 [29], AtMYBL2 [30] and PpMYB18 [31]. The study confirmed that BcMYB44 belonged to R2R3-MYB and had the same two MYB domains and transcriptional suppression of the LSLSL subdomain with other closely related MYB44 proteins, which was consistent with the findings of Wei et al [11].…”

The Paeonia qiui R2R3-MYB Transcription Factor PqMYBF1 Positively Regulates Flavonol Accumulation

“…In our previous studies, some flavonoid biosynthesis-related R2R3-MYBs were found in P. qiui through transcriptome sequencing [ 30 ]. Among them, two R2R3-MYBs (PqMYB113 and PqMYB4) were isolated, and their biological functions were verified in anthocyanin biosynthesis [ 31 , 32 ]. In this study, another flavonoid (flavonol) biosynthesis activator, PqMYBF1 from the leaves of P. qiui , was characterized, and the biological function of PqMYBF1 was investigated using genetically modified tobacco, which will enrich our knowledge about tree peony leaf color variation in spring.…”

Comparative Transcriptome Analysis Reveals Key Functions of MiMYB Gene Family in Macadamia Nut Pericarp Formation

“…MYB plays an important role in regulating plant cell growth and development, abiotic stress and biotic stress, and metabolic reactions. The regulatory role of MYB family members in plant fruit traits mainly includes the direct regulation of pericarp thickness and the regulation of the active ingredients in fruit [28][29][30]. Based on a genome study of the Guire No.1 variety [23], a transcriptome analysis was performed of macadamia nut varieties A38, Guire No.1, and HAES900, with significant differences in pericarp thickness.…”