The microRNA regulated SBP-box genes SPL9 and SPL15 control shoot maturation in Arabidopsis

Plant Mol Biol. 2008 May;67(1-2):183-95. doi: 10.1007/s11103-008-9310-z. Epub 2008 Feb 17.


Throughout development the Arabidopsis shoot apical meristem successively undergoes several major phase transitions such as the juvenile-to-adult and floral transitions until, finally, it will produce flowers instead of leaves and shoots. Members of the Arabidopsis SBP-box gene family of transcription factors have been implicated in promoting the floral transition in dependence of miR156 and, accordingly, transgenics constitutively over-expressing this microRNA are delayed in flowering. To elaborate their roles in Arabidopsis shoot development, we analysed two of the 11 miR156 regulated Arabidopsis SBP-box genes, i.e. the likely paralogous genes SPL9 and SPL15. Single and double mutant phenotype analysis showed these genes to act redundantly in controlling the juvenile-to-adult phase transition. In addition, their loss-of-function results in a shortened plastochron during vegetative growth, altered inflorescence architecture and enhanced branching. In these aspects, the double mutant partly phenocopies constitutive MIR156b over-expressing transgenic plants and thus a major contribution to the phenotype of these transgenics as a result of the repression of SPL9 and SPL15 is strongly suggested.

MeSH terms

  • Alleles
  • Amino Acid Motifs
  • Arabidopsis / anatomy & histology
  • Arabidopsis / genetics*
  • Arabidopsis / growth & development
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Arabidopsis Proteins / physiology*
  • Gene Expression Regulation, Plant*
  • Gibberellins / pharmacology
  • Gibberellins / physiology
  • MicroRNAs / physiology*
  • Phenotype
  • Phylogeny
  • Plant Growth Regulators / pharmacology
  • Plant Growth Regulators / physiology
  • Plant Leaves / anatomy & histology
  • Plant Leaves / genetics
  • Plant Leaves / growth & development
  • Plant Shoots / anatomy & histology
  • Plant Shoots / genetics
  • Plant Shoots / growth & development
  • Trans-Activators
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*


  • Arabidopsis Proteins
  • Gibberellins
  • MicroRNAs
  • Plant Growth Regulators
  • SPL15 protein, Arabidopsis
  • SPL9 protein, Arabidopsis
  • Trans-Activators
  • Transcription Factors