Study of the three-dimensional architecture of plant cells

Since 2004 we are interested in three-dimensional reconstruction of organelles, whole plant cells or specific cell regions to study various aspects of plant cell structure, such as the cell plate (Seguí-Simarro and Staehelin, 2006b), phragmoplast microtubules (Austin et al., 2005, Seguí-Simarro et al., 2008b), the Golgi apparatus, vacuoles and multivesicular bodies (Seguí-Simarro and Staehelin, 2006a). For this, we use 3D reconstruction techniques such as serial section reconstructions and dual-axis electron tomography, both of them based on transmission electron microscopy.

In particular, in recent years we have been studying the presence of a special type of reticulated mitochondria, forming a dynamic three-dimensional network (Figure 1) around the nucleus of certain meristematic cell types, characterized by their high rate of proliferation and undifferentiated state. The presence of these mitochondria, never before described in higher plants, and their associated mitochondrial cycle, has important implications for both cellular energetics and plant reproduction, since reticulated mitochondria form a common space within which the mitochondrial DNA (mtDNA) can be homogenized and recombine, so that daughter cells receive a mtDNA copy as homogeneous as the original. This collaboration has resulted in several contributions in national and international meetings and especially research papers (Segui-Simarro and Staehelin, 2009; Seguí-Simarro et al. 2008a).

3DArchitecture1

Figure 1: The cycle of mitochondria mitochondrial reticulum of the apical meristem cells of Arabidopsis thaliana. Image adapted from Seguí-Simarro et al (2008). Plant Physiology. 148 (3) :1380-1393.

 

Currently, we are applying these techniques, in particular electron tomography, to the study of the architecture and spatial distribution of the different structures involved in post-transcriptional RNA processing, present in the nucleoplasm of the plant cell nucleus (Figure 2).

3DArchitecture2

Figure 2: Electron tomographic model of a plant (Brassica napus) cell nucleus and the different structures present in the interchromatin regions.

 

 

 

References

 

Seguí-Simarro, J.M., Austin, J.R., White, E.A. y Staehelin, L.A. (2004). Electron tomographic analysis of somatic cell plate formation in meristematic cells of arabidopsis preserved by high-pressure freezing. Plant Cell 16, 836-856.

 

Austin, J.R., Seguí-Simarro, J.M. y Staehelin, L.A. (2005). Quantitative analysis of changes in spatial distribution and plus-end geometry of microtubules involved in plant-cell cytokinesis. J. Cell. Sci. 118, 3895-3903.

 

Seguí-Simarro, J.M. y Staehelin, L.A. (2006a). Cell cycle-dependent changes in Golgi stacks, vacuoles, clathrin-coated vesicles and multivesicular bodies in meristematic cells of Arabidopsis thaliana: a quantitative and spatial analysis. Planta 223, 223.

 

Seguí-Simarro, J.M. y Staehelin, L.A. (2006b). Mechanisms of cytokinesis in flowering plants: new pieces for an old puzzle. Floriculture, Ornamental and Plant Biotechnology: Advances and Topical Issues, J.A. Teixeira da Silva, ed (London: Global Science Books), pp. 185-196.

 

Seguí-Simarro, J.M., Coronado, M.J. y Staehelin, L.A. (2008a). The mitochondrial cycle of Arabidopsis shoot apical meristem and leaf primordium meristematic cells is defined by a perinuclear tentaculate/cage-like mitochondrion. Plant Physiol. 148, 1380-1393.

 

Seguí-Simarro, J.M., Otegui, M.S., Austin, J.R. y Staehelin, L.A. (2008b). Plant cytokinesis - Insights gained from electron tomography studies. Cell Division Control in Plants, D.P.S. Verma y Z. Hong, eds (Berlin/Heidelberg: Springer), pp. 251-287.

 

Segui-Simarro, J.M. y Staehelin, L.A. (2009). Mitochondrial reticulation in shoot apical meristem cells of Arabidopsis provides a mechanism for homogenization of mtDNA prior to gamete formation. Plant Signal Behav 4, 168-171.

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Grupo de Biología Celular

  • e-mail: seguisim@btc.upv.es
  • Teléfono: (+34)963879047
                 (+34)963877000 ext 88472(Lab.)
  • Localización: Edificio 8E - Acceso I - Planta 1
  • CPI - Universidad Politécnica de Valencia