title: Two MYB transcription factors regulate flavonoid biosynthesis in pear fruit (Pyrus bretschneideri Rehd.).
abstract: Flavonoid compounds play important roles in the modern diet, and pear fruits are an excellent dietary source of these metabolites. However, information on the regulatory network of flavonoid biosynthesis in pear fruits is rare. In this work, 18 putative flavonoid-related MYB transcription factors (TFs) were screened by phylogenetic analysis and four of them were correlated with flavonoid biosynthesis patterns in pear fruits. Among these MYB-like genes, the specific functions of two novel MYB TFs, designated as PbMYB10b and PbMYB9, were further verified by both overexpression and RNAi transient assays. PbMYB10b, a PAP-type MYB TF with atypical motifs in its conserved region, regulated the anthocyanin and proanthocyanidin pathways by inducing the expression of PbDFR, but its function could be complemented by other MYB TFs. PbMYB9, a TT2-type MYB, not only acted as the specific activator of the proanthocyanidin pathway by activating the PbANR promoter, but also induced the synthesis of anthocyanins and flavonols by binding the PbUFGT1 promoter in pear fruits. The MYBCORE-like element has been identified in both the PbUFGT1 promoter and ANR promoters in most species, but it was not found in UFGT promoters isolated from other species. This finding was also supported by a yeast one-hybrid assay and thus enhanced the likelihood of the interaction between PbMYB9 and the PbUFGT1 promoter.
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhai
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China.
authors.forename: Shiwei
authors.initials: S
authors.lastname: Zhang
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China.
authors.forename: Geng
authors.initials: G
authors.lastname: Meng
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China.
authors.forename: Linyan
authors.initials: L
authors.lastname: Song
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China.
authors.forename: Pengmin
authors.initials: P
authors.lastname: Li
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China.
authors.forename: Fengwang
authors.initials: F
authors.lastname: Ma
authors.affiliation: College of Horticulture, Northwest A&F University, Taicheng Road NO.3, Yangling, Shaanxi Province, China lingfxu2013@sina.com.
authors.forename: Lingfei
authors.initials: L
authors.lastname: Xu
mesh_terms: D000595:Amino Acid Sequence; D053898:Biosynthetic Pathways; D003001:Cloning, Molecular; D005419:Flavonoids / Q000096:biosynthesis*; D005638:Fruit / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D031989:Pyrus / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D005419:Flavonoids; D010940:Plant Proteins; D014157:Transcription Factors
keywords: Flavonoid; MYB transcription factors; pear fruit; plant secondary metabolism; regulatory network; transient.