MAP20, a Microtubule-Associated Protein in the Secondary Cell Walls of Hybrid Aspen, Is a Target of the Cellulose Synthesis Inhibitor 2,6-Dichlorobenzonitrile

Alex S. Rajangam, Manoj Kumar, Henrik Aspeborg, Gea Guerriero, Lars Arvestad, Podjamas Pansri, Christian J. -L. Brown, Sophia Hober, Kristina Blomqvist, Christina Divne, Ines Ezcurra, Ewa Mellerowicz, Bjorn Sundberg, Vincent Bulone, Tuula T. Teeri*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

We have identified a gene, denoted PttMAP20, which is strongly up-regulated during secondary cell wall synthesis and tightly coregulated with the secondary wall-associated CESA genes in hybrid aspen (Populus tremula x tremuloides). Immunolocalization studies with affinity-purified antibodies specific for PttMAP20 revealed that the protein is found in all cell types in developing xylem and that it is most abundant in cells forming secondary cell walls. This PttMAP20 protein sequence contains a highly conserved TPX2 domain first identified in a microtubule-associated protein (MAP) in Xenopus laevis. Overexpression of PttMAP20 in Arabidopsis (Arabidopsis thaliana) leads to helical twisting of epidermal cells, frequently associated with MAPs. In addition, a PttMAP20-yellow fluorescent protein fusion protein expressed in tobacco (Nicotiana tabacum) leaves localizes to microtubules in leaf epidermal pavement cells. Recombinant PttMAP20 expressed in Escherichia coli also binds specifically to in vitro-assembled, taxol-stabilized bovine microtubules. Finally, the herbicide 2,6-dichlorobenzonitrile, which inhibits cellulose synthesis in plants, was found to bind specifically to PttMAP20. Together with the known function of cortical microtubules in orienting cellulose microfibrils, these observations suggest that PttMAP20 has a role in cellulose biosynthesis.

Original languageEnglish
Pages (from-to)1283-1294
Number of pages12
JournalPLANT PHYSIOLOGY
Volume148
Issue number3
DOIs
Publication statusPublished - Nov 2008
MoE publication typeA1 Journal article-refereed

Keywords

  • CARBOHYDRATE-ACTIVE ENZYMES
  • PLANT FUNCTIONAL GENOMICS
  • KINESIN-LIKE PROTEIN
  • CORTICAL MICROTUBULES
  • PLASMA-MEMBRANE
  • WOOD FORMATION
  • ARABIDOPSIS-THALIANA
  • CONIFER TRACHEIDS
  • ANGIOSPERM TREES
  • UREA SOLUTION

Cite this