title: Genome-wide analysis of the R2R3-MYB transcription factor genes in Chinese cabbage (Brassica rapa ssp. pekinensis) reveals their stress and hormone responsive patterns.
abstract: BACKGROUND
  The MYB superfamily is one of the most abundant transcription factor (TF) families in plants. MYB proteins include highly conserved N-terminal MYB repeats (1R, R2R3, 3R, and atypical) and various C-terminal sequences that confer extensive functions. However, the functions of most MYB genes are unknown, and have been little studied in Chinese cabbage.
  
  
  RESULTS
  Here, we analyzed 256 (55.2% of total MYBs) R2R3-MYB genes from Chinese cabbage (Brassica rapa ssp. pekinensis) and anchored them onto the 10 chromosomes and three subgenomes. The R2R3-, 3R- and atypical MYB proteins in Chinese cabbage formed 45 subgroups based on domain similarity and phylogenetic topology. Organization and syntenic analysis revealed the genomic distribution and collinear relationships of the R2R3-BrMYBs. Synonymous nucleotide substitution (Ka/Ks) analysis showed that the Chinese cabbage MYB DNA-binding domain is under strong purifying selection. Moreover, RNA-seq data revealed tissue-specific and distinct R2R3-BrMYB expression profiles, and quantitative real-time PCR (qPCR) analysis in leaves showed stress responsive expression and crosstalk with ABA-auxin signaling cascades.
  
  
  CONCLUSIONS
  In this study, we identified the largest MYB gene family in plants to date. Our results indicate that members of this superfamily may be involved in plant development, stress responses and leaf senescence, highlighting their functional diversity.
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. 2012204016@njau.edu.cn.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. t.jun525@163.com.|Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China. t.jun525@163.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. 2013804134@njau.edu.cn.
authors.forename: Rong
authors.initials: R
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. 2013104083@njau.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. hxl@njau.edu.cn.
authors.forename: Xi-Lin
authors.initials: XL
authors.lastname: Hou
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. 2011204015@njau.edu.cn.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Song
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. xiongaisheng@njau.edu.cn.
authors.forename: Ai-Sheng
authors.initials: AS
authors.lastname: Xiong
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001937:Brassica / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D002681:China; D002874:Chromosome Mapping; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018745:Genome, Plant; D007210:Indoleacetic Acids / Q000494:pharmacology; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D017423:Sequence Analysis, RNA; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; D014157:Transcription Factors; D000040:Abscisic Acid