The role of the cytoskeleton in the morphogenesis and function of stomatal complexes

Authors


Author for correspondence:Basil Galatis Tel: +003 210 7274646 Fax: +003 210 7274702 Email: bgalatis@biol.uoa.gr

Abstract

Contents

  • Summary000

  • I. Introduction000
  • II. Cytoskeleton and development of the stomatal complexes000
  • III. Cytoskeleton and stomatal cell shaping000
  • IV. Stomatal pore formation000
  • V. Substomatal cavity formation000
  • VI. Stomatal complex morphogenesis in mutants000
  • VII. Cytoskeleton dynamics in functioning stomata000
  • VIII. Mechanisms of microtubule organization in stomatal cells000
  • IX. Conclusions-perspectives000
  • References000

Summary

Microtubules (MTs) and actin filaments (AFs) form highly organized arrays in stomatal cells that play key roles in the morphogenesis of stomatal complexes. The cortical MTs controlling the orientation of the depositing cellulose microfibrils (CMs) and affecting the pattern of local wall thickenings define the mechanical properties of the walls of stomatal cells, thus regulating accurately their shape. Besides, they are involved in determination of the cell division plane. Substomatal cavity and stomatal pore formation are also MT-dependent processes. Among the cortical MT arrays, the radial ones lining the periclinal walls are of particular morphogenetic importance. Putative MT organizing centers (MTOCs) function at their focal regions, at least in guard cells (GCs), or alternatively, these regions either organize or nucleate cortical MTs. AFs are involved in cell polarization preceding asymmetrical divisions, in determination of the cell division plane and final cell plate alignment and probably in transduction of stimuli implicated in stomatal complex morphogenesis. Mature kidney-shaped GCs display radial AF arrays, undergoing definite organization cycles during stomatal movement. They are involved in stomatal movement, probably by controlling plasmalemma ion-channel activities. Radial MT arrays also persist in mature GCs, but a role in stomatal function cannot yet be attributed to them.

Ancillary