Isolation and Molecular Characterization of Thirteen R2R3-MYB Transcription Factors from Epimedium sagittatum

Wenjun Huang,Gong Xiao,Wei Sun,Shaohua Zeng,Haiyan Lv,Ying Wang

doi:10.3390/ijms14010594

Abstract

Epimedium sagittatum (Sieb. et Zucc.) Maxim, a popular traditional Chinese medicinal plant, has been widely used for treating sexual dysfunction and osteoporosis in China. The main bioactive components in herba epimedii are prenylated flavonol glycosides, which are end products of a branch of the flavonoid biosynthetic pathway. The MYB transcription factors (TF) act as activators or repressors to regulate the flavonoid pathway. In this study, 13 full-length cDNA clones of R2R3-MYB TFs from E. sagittatum (designated as EsMYB1 to EsMYB13) were isolated and characterized. Sequence similarity and phylogenetic analysis placed nine R2R3-MYB members of E. sagittatum into five subgroups of the Arabidopsis R2R3-MYB family, while four members were not clustered into a defined subgroup. The number and length of introns from Epimedium R2R3-MYB genes varied significantly, but intron positions and phases were well conserved. Expression patterns of Epimedium R2R3-MYB genes in various tissues showed diverse. Finally, it is suggested that five Epimedium R2R3-MYB genes may be involved in regulating the flavonoid pathway and could be used as valuable candidate genes for metabolic engineering studies in future. Sequence information of 13 R2R3-MYB genes discovered here will also provide an entry point into the overview of whole R2R3-MYB family in Epimedium.

Highlights

Transcription factors (TFs) play a central role in developmental and metabolic programs by regulating the transcription expression of downstream target genes
A total of 13 full-length cDNA clones of R2R3-MYBTFs were isolated from leaves of E. sagittatum using homology-based cloning, RACE technology and fishing for candidate ESTs encoding MYB proteins in the Epimedium EST database [25]
All Epimedium R2R3-MYB sequences contained the R2 and R3 MYB domain identified through conserved domain analysis, placing them in the large R2R3-MYB family (Figure 1a)

Summary

Introduction

Transcription factors (TFs) play a central role in developmental and metabolic programs by regulating the transcription expression of downstream target genes. The MYB proteins comprise one of the largest TF families in the plant kingdom [1,2]. MYB proteins have two distinct regions, an. N-terminal conserved MYB DNA-binding domain (MYB domain) and a diverse C-terminal modulator region that is responsible for the regulatory activity of the protein. The MYB domain is highly conserved among plants, yeast and animals [3], and its consensus sequence contains approximately. Based on the number of MYB domain, the MYB family can be divided into four classes, 1R-, R2R3-, 3R- and 4R-MYB proteins [2,5]. Plant R2R3-MYB proteins play an important role in many biological processes including primary and secondary metabolism, cell fate and identity, developmental processes and responses to biotic and abiotic stress [5,9,10]

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