Increased leaf mesophyll porosity following transient retinoblastoma-related protein silencing is revealed by microcomputed tomography imaging and leads to a system-level physiological response to the altered cell division pattern

Plant J. 2013 Dec;76(6):914-29. doi: 10.1111/tpj.12342. Epub 2013 Nov 11.


The causal relationship between cell division and growth in plants is complex. Although altered expression of cell-cycle genes frequently leads to altered organ growth, there are many examples where manipulation of the division machinery leads to a limited outcome at the level of organ form, despite changes in constituent cell size. One possibility, which has been under-explored, is that altered division patterns resulting from manipulation of cell-cycle gene expression alter the physiology of the organ, and that this has an effect on growth. We performed a series of experiments on retinoblastoma-related protein (RBR), a well characterized regulator of the cell cycle, to investigate the outcome of altered cell division on leaf physiology. Our approach involved combination of high-resolution microCT imaging and physiological analysis with a transient gene induction system, providing a powerful approach for the study of developmental physiology. Our investigation identifies a new role for RBR in mesophyll differentiation that affects tissue porosity and the distribution of air space within the leaf. The data demonstrate the importance of RBR in early leaf development and the extent to which physiology adapts to modified cellular architecture resulting from altered cell-cycle gene expression.

Keywords: Arabidopsis thaliana; cell cycle; development; imaging; leaf; physiology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anthocyanins / analysis
  • Anthocyanins / metabolism
  • Arabidopsis / cytology
  • Arabidopsis / genetics
  • Arabidopsis / growth & development
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cell Cycle
  • Cell Differentiation
  • Cell Size
  • Chlorophyll / metabolism
  • Gene Expression Regulation, Plant*
  • Genes, Reporter
  • Mesophyll Cells / cytology
  • Mesophyll Cells / physiology
  • Phenotype
  • Photosystem II Protein Complex / physiology
  • Plant Epidermis / cytology
  • Plant Epidermis / genetics
  • Plant Epidermis / growth & development
  • Plant Epidermis / physiology
  • Plant Leaves / cytology
  • Plant Leaves / genetics
  • Plant Leaves / growth & development
  • Plant Leaves / physiology
  • Plant Stomata / cytology
  • Plant Stomata / genetics
  • Plant Stomata / growth & development
  • Plant Stomata / physiology
  • Plant Transpiration / physiology
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism
  • RNA Interference
  • RNA, Messenger / genetics
  • X-Ray Microtomography / methods*


  • Anthocyanins
  • Arabidopsis Proteins
  • Photosystem II Protein Complex
  • RBR1 protein, Arabidopsis
  • RNA, Messenger
  • Chlorophyll