Organization of cortical microtubules at the plasma membrane in Arabidopsis

Abstract

To understand the role of microtubules in the regulation of cell elongation, we characterized microtubule patterns in fass, a cell shape mutant of Arabidopsis thaliana (L.) Heynh. Examining microtubule patterns via immunocytochemistry, we found that fass cells were able to organize their microtubules into mitotic spindles and phragmoplasts. During interphase or preprophase, fass cells had cortical microtubules, verified by transmission electron microscopy, but these microtubules were not organized into the cortical array or preprophase band. Using chromatin condensation and tubulin localization on the nuclear envelope as preprophase stage markers, we found that although fass cells lacked the preprophase band and cortical array, their cell division cycle appeared normal. To pinpoint the defect in fass cells, we delineated the sequential events leading to cortical array formation in Arabidopsis cells and found that fass cells initiated and recolonized cortical microtubules in the same manner as wild-type cells, but failed to order them into the cortical array. Taken together, these results suggest fass cells are impaired in a component of the microtubule organizing center(s) required for the proper ordering of cortical microtubules at the plasma membrane.

New Techniques Enable Comparative Analysis of Microtubule Orientation, Wall Texture, and Growth Rate in Intact Roots of Arabidopsis

“…This is consistent with observations made in a wide range of cell types (Clayton et al, 1985;Wick, 1985;Flanders et al, 1990;Nagata and Hasezawa, 1993;Baskin et al, 1999;Bichet et al, 2000;Wenzel et al, 2000). Arabidopsis mutants with apparently normal division patterns but random cortical arrays including fass (McClinton and Sung, 1997) and botero1 (Bichet et al, 2000) may help identify the mechanism for establishing transverse CMTs. In the botero1 mutant, CMTs fail to consolidate into transverse arrays as cells enter the elongation zone and growth anisotropy is impaired (Bichet et al, 2000).…”

Tangled localization at the cortical division site of plant cells occurs by several mechanisms

“…7, TAN is recruited to the CDS initially as the PPB forms. This initial recruitment requires microtubules as well as FASS (Walker et al, 2007), a PP2A phosphatase BЉ regulatory subunit (Camilleri et al, 2002), which is also required for PPB formation (McClinton and Sung, 1997). In this study, we show that the initial recruitment and early maintenance of TAN at the CDS is mediated by Region II of TAN.…”

“…For example, Adiantum capilus-veneris cells lacking PPBs show late phragmoplast misorientation and oblique cell plate insertion (Mineyuki et al, 1991). In Arabidopsis thaliana (McClinton and Sung, 1997;Camilleri et al, 2002;Kawamura et al, 2006;Azimzadeh et al, 2008) and Zea mays , mutants that fail to make PPBs display cells with random planes of division. Cultured A. thaliana (Chan et al, 2005) and tobacco cells (Vanstraelen et al, 2006) lacking PPBs also exhibit random division planes.…”

Fertilization-induced changes in the microtubular architecture of the maize egg cell and zygote—an immunocytochemical approach adapted to single cells

“…During interphase they remain close to the plasma membrane (Ledbetter and Porter 1963;Newcomb 1969;Seagull and Heath 1980;McClinton and Sung 1997).…”