Forever Young: The Role of Ubiquitin Receptor DA1 and E3 Ligase BIG BROTHER in Controlling Leaf Growth and Development

Plant Physiol. 2017 Feb;173(2):1269-1282. doi: 10.1104/pp.16.01410. Epub 2016 Dec 21.


The final size of plant organs is determined by a combination of cell proliferation and cell expansion. Leaves account for a large part of above-ground biomass and provide energy to complete the plant's life cycle. Although the final size of leaves is remarkably constant under fixed environmental conditions, several genes have been described to enhance leaf growth when their expression is modulated. In Arabidopsis (Arabidopsis thaliana), mutations in DA1 and BB increase leaf size, an effect that is synergistically enhanced in the double mutant. Here, we show that overexpression of a dominant-negative version of DA1 enhances leaf size in a broad range of natural accessions of this species, indicating a highly conserved role of this protein in controlling organ size. We also found that during early stages of development, leaves of da1-1 and bb/eod1-2 mutants were already larger than the isogenic Col-0 wild type, but this phenotype was triggered by different cellular mechanisms. Later during development, da1-1 and bb/eod1-2 leaves showed a prolonged longevity, which was enhanced in the double mutant. Conversely, ectopic expression of DA1 or BB restricted growth and promoted leaf senescence. In concert, shortly upon induction of DA1 and BB expression, several marker genes for the transition from proliferation to expansion were highly up-regulated. Additionally, multiple genes involved in maintaining the mitotic cell cycle were rapidly down-regulated and senescence genes were strongly up-regulated, particularly upon BB induction. With these results, we demonstrate that DA1 and BB restrict leaf size and promote senescence through converging and different mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cell Proliferation
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant
  • LIM Domain Proteins / genetics
  • LIM Domain Proteins / metabolism*
  • Organ Size / genetics
  • Plant Cells
  • Plant Leaves / genetics
  • Plant Leaves / growth & development*
  • Plant Leaves / metabolism
  • Plants, Genetically Modified
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism*


  • Arabidopsis Proteins
  • DA1 protein, Arabidopsis
  • LIM Domain Proteins
  • BIG BROTHER protein, Arabidopsis
  • Ubiquitin-Protein Ligases