POM-POM2/cellulose synthase interacting1 is essential for the functional association of cellulose synthase and microtubules in Arabidopsis

Plant Cell. 2012 Jan;24(1):163-77. doi: 10.1105/tpc.111.093575. Epub 2012 Jan 31.

Abstract

In plants, regulation of cellulose synthesis is fundamental for morphogenesis and plant growth. Cellulose is synthesized at the plasma membrane, and the orientation of synthesis is guided by cortical microtubules; however, the guiding mechanism is currently unknown. We show that the conditional root elongation pom2 mutants are impaired in cell elongation, fertility, and microtubule-related functions. Map-based cloning of the POM-POM2 locus revealed that it is allelic to CELLULOSE SYNTHASE INTERACTING1 (CSI1). Fluorescently tagged POM2/CSI1s associated with both plasma membrane-located cellulose synthases (CESAs) and post-Golgi CESA-containing compartments. Interestingly, while CESA insertions coincided with cortical microtubules in the pom2/csi1 mutants, the microtubule-defined movement of the CESAs was significantly reduced in the mutant. We propose that POM2/CSI1 provides a scaffold between the CESAs and cortical microtubules that guide cellulose synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Fertility / genetics
  • Fertility / physiology
  • Glucosyltransferases / genetics
  • Glucosyltransferases / metabolism
  • Microtubules / metabolism*

Substances

  • Arabidopsis Proteins
  • CSI1 protein, Arabidopsis
  • Carrier Proteins
  • Glucosyltransferases
  • cellulose synthase (GDP-forming)