title: Transcriptome-wide profiling and expression analysis of transcription factor families in a liverwort, Marchantia polymorpha.
abstract: BACKGROUND
  Transcription factors (TFs) are vital elements that regulate transcription and the spatio-temporal expression of genes, thereby ensuring the accurate development and functioning of an organism. The identification of TF-encoding genes in a liverwort, Marchantia polymorpha, offers insights into TF organization in the members of the most basal lineages of land plants (embryophytes). Therefore, a comparison of Marchantia TF genes with other land plants (monocots, dicots, bryophytes) and algae (chlorophytes, rhodophytes) provides the most comprehensive view of the rates of expansion or contraction of TF genes in plant evolution.
  
  
  RESULTS
  In this study, we report the identification of TF-encoding transcripts in M. polymorpha for the first time, as evidenced by deep RNA sequencing data. In total, 3,471 putative TF encoding transcripts, distributed in 80 families, were identified, representing 7.4% of the generated Marchantia gametophytic transcriptome dataset. Overall, TF basic functions and distribution across families appear to be conserved when compared to other plant species. However, it is of interest to observe the genesis of novel sequences in 24 TF families and the apparent termination of 2 TF families with the emergence of Marchantia. Out of 24 TF families, 6 are known to be associated with plant reproductive development processes. We also examined the expression pattern of these TF-encoding transcripts in six male and female developmental stages in vegetative and reproductive gametophytic tissues of Marchantia.
  
  
  CONCLUSIONS
  The analysis highlighted the importance of Marchantia, a model plant system, in an evolutionary context. The dataset generated here provides a scientific resource for TF gene discovery and other comparative evolutionary studies of land plants.
authors.forename: Niharika
authors.initials: N
authors.lastname: Sharma
authors.forename: Prem L
authors.initials: PL
authors.lastname: Bhalla
authors.affiliation: Plant Molecular Biology and Biotechnology Laboratory, Australian Research Council Centre of Excellence for Integrative Legume Research, Melbourne School of Land and Environment, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia. mohan@unimelb.edu.au.
authors.forename: Mohan B
authors.initials: MB
authors.lastname: Singh
mesh_terms: D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D047008:Marchantia / Q000235:genetics*; D005810:Multigene Family; D010940:Plant Proteins / Q000235:genetics*; D017423:Sequence Analysis, RNA; D014157:Transcription Factors / Q000235:genetics*; D059467:Transcriptome
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors