Re-orientation of cortical F-actin is not necessary for wound-induced microtubule re-orientation and cell polarity establishment

Julia M. Hush*, R. L. Overall

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

To assess the relative roles of cortical actin and microtubule re-orientation in the establishment of new cell polarity, we have examined the kinetics of cortical actin re-orientation around a wedge-shaped wound in pea roots. Cortical actin re-orients from a transverse alignment to an approximately longitudinal orientation between 5 and 24h after wounding, that is, after the re-alignment of microtubules, which is known to occur before 5h post-wounding. F-actin in root cortical cells does not appear to be necessary for the establishment of new cell polarity around wounds, since normal MT re-alignment, and new planes of cell division are still established around a wound in cytochalasin treated roots. The cytochalasin treatment appeared to totally disrupt cortical and cytoplasmic F-actin in cells of the root cortex. However, in the apparent absence of F-actin in these cells, the rate of wound-induced cell division, but not cell expansion, is slower, and we suggest that an effect on the phragmosomal actin is involved. Finally, we demonstrate that new cell polarity around a wound is not established if microtubules are disrupted by the herbicide oryzalin, but after re-establishment of these arrays following a wash-out of the drug, the typical new planes of cell expansion are observed. We conclude that microtubules play a critical role in establishing and maintaining cell polarity in this system, and that cortical F-actin has a minor and presently unclear function in these processes.

Original languageEnglish
Pages (from-to)97-106
Number of pages10
JournalProtoplasma
Volume169
Issue number3-4
DOIs
Publication statusPublished - Sept 1992
Externally publishedYes

Keywords

  • Actin
  • Cytoskeleton
  • Microtubules
  • Pea root
  • Polarity
  • Wound

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