title: Some ethylene biosynthesis and AP2/ERF genes reveal a specific pattern of expression during somatic embryogenesis in Hevea brasiliensis.
abstract: BACKGROUND
  Ethylene production and signalling play an important role in somatic embryogenesis, especially for species that are recalcitrant in in vitro culture. The AP2/ERF superfamily has been identified and classified in Hevea brasiliensis. This superfamily includes the ERFs involved in response to ethylene. The relative transcript abundance of ethylene biosynthesis genes and of AP2/ERF genes was analysed during somatic embryogenesis for callus lines with different regeneration potential, in order to identify genes regulated during that process.
  
  
  RESULTS
  The analysis of relative transcript abundance was carried out by real-time RT-PCR for 142 genes. The transcripts of ERFs from group I, VII and VIII were abundant at all stages of the somatic embryogenesis process. Forty genetic expression markers for callus regeneration capacity were identified. Fourteen markers were found for proliferating calli and 35 markers for calli at the end of the embryogenesis induction phase. Sixteen markers discriminated between normal and abnormal embryos and, lastly, there were 36 markers of conversion into plantlets. A phylogenetic analysis comparing the sequences of the AP2 domains of Hevea and Arabidopsis genes enabled us to predict the function of 13 expression marker genes.
  
  
  CONCLUSIONS
  This first characterization of the AP2/ERF superfamily in Hevea revealed dramatic regulation of the expression of AP2/ERF genes during the somatic embryogenesis process. The gene expression markers of proliferating callus capacity to regenerate plants by somatic embryogenesis should make it possible to predict callus lines suitable to be used for multiplication. Further functional characterization of these markers opens up prospects for discovering specific AP2/ERF functions in the Hevea species for which somatic embryogenesis is difficult.
authors.affiliation: CIRAD, UMR AGAP, F-34398, Montpellier, France.
authors.forename: Piyanuch
authors.initials: P
authors.lastname: Piyatrakul
authors.forename: Riza-Arief
authors.initials: RA
authors.lastname: Putranto
authors.forename: Florence
authors.initials: F
authors.lastname: Martin
authors.forename: Maryannick
authors.initials: M
authors.lastname: Rio
authors.forename: Florence
authors.initials: F
authors.lastname: Dessailly
authors.forename: Julie
authors.initials: J
authors.lastname: Leclercq
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dufayard
authors.forename: Ludovic
authors.initials: L
authors.lastname: Lardet
authors.forename: Pascal
authors.initials: P
authors.lastname: Montoro
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D005030:Ethylenes / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D028482:Hevea / Q000235:genetics*; D005810:Multigene Family; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics; D058439:Plant Somatic Embryogenesis Techniques; D018749:RNA, Plant / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D059467:Transcriptome
chemical_list: D005030:Ethylenes; D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors; C036216:ethylene