The association of peroxisomes with the developing cell plate in dividing onion root cells depends on actin microfilaments and myosin

Abstract

We have investigated changes in the distribution of peroxisomes through the cell cycle in onion ( Allium cepa L.) root meristem cells with immunofluorescence and electron microscopy, and in leek ( Allium porrum L.) epidermal cells with immunofluorescence and peroxisomal-targeted green fluorescent protein. During interphase and mitosis, peroxisomes distribute randomly throughout the cytoplasm, but beginning late in anaphase, they accumulate at the division plane. Initially, peroxisomes occur within the microtubule phragmoplast in two zones on either side of the developing cell plate. However, as the phragmoplast expands outwards to form an annulus, peroxisomes redistribute into a ring immediately inside the location of the microtubules. Peroxisome aggregation depends on actin microfilaments and myosin. Peroxisomes first accumulate in the division plane prior to the formation of the microtubule phragmoplast, and throughout cytokinesis, always co-localise with microfilaments. Microfilament-disrupting drugs (cytochalasin and latrunculin), and a putative inhibitor of myosin (2,3-butanedione monoxime), inhibit aggregation. We propose that aggregated peroxisomes function in the formation of the cell plate, either by regulating hydrogen peroxide production within the developing cell plate, or by their involvement in recycling of excess membranes from secretory vesicles via the beta-oxidation pathway. Differences in aggregation, a phenomenon which occurs in onion, some other monocots and to a lesser extent in tobacco BY-2 suspension cells, but which is not obvious in the roots of Arabidopsis thaliana (L.) Heynh., may reflect differences within the primary cell walls of these plants.

Endoplasmic reticulum targeted GFP reveals ER organization in tobacco NT-1 cells during cell division

“…Spindle orientation was determined by observation of chromosomes, either from DIC images, or in optical series where transmitted light images were not collected, from observing the regions in the spindle from which ER was excluded (see also below). 8 As the chromosomes migrated toward the poles of the cell during anaphase, they continued to be encompassed by tubes of ER, and ER filled the space between the separating sets of chromosomes (Fig. 2, 40 min, arrows; Fig.…”

“…For example, the localization of the Golgi apparatus into the so-called Golgi-belt in cytokinetic tobacco BY-2 cells does not depend on either actin or microtubules [29], whereas the redistribution of peroxisomes into a phragmoplast-linked band in dividing onion root tip cells is strictly actin-dependent [8]. Microtubules, however, may be involved in the delivery of ER-derived vesicles to the phragmoplast of cytokinetic 18 Arabidopsis cells through the interaction of a vesicle-localized kinesin, AtPAKRP2, with microtubules [23].…”

A Comparative Study of the Involvement of 17 Arabidopsis Myosin Family Members on the Motility of Golgi and Other Organelles

“…Plant myosins have been implicated in various cellular activities, such as cytoplasmic streaming (Shimmen and Yokota, 2004;Esseling-Ozdoba et al, 2008), plasmodesmata function (Baluska et al, 2001;Volkmann et al, 2003), organelle movement (Nebenfü hr et al, 1999;Jedd and Chua, 2002), cytokinesis (Molchan et al, 2002;Collings et al, 2003;Volkmann et al, 2003), endocytosis (Volkmann et al, 2003;Baluska et al, 2004;Samaj et al, 2005), and targeted RNA transport (Hamada et al, 2003). Actomyosin mediated cytoplasmic streaming found in various algae cells reach velocities of up to 100 mm s 21 , which is the fastest known myosin-mediated movement (Shimmen and Yokota, 1994).…”

The N-terminal TOG domain of Arabidopsis MOR1 modulates affinity for microtubule polymers

“…For N-terminal fusion proteins, constructs were expressed transiently in the epidermal cells of 2 cm 2 pieces of leek (Allium porrum L.) leaf by particle bombardment (model PDS-1000, 1100 psi rupture discs; Bio-Rad, Regents Park, NSW, Australia) (Collings et al, 2003). Plant tissue was incubated overnight before being imaged or processed for immunofluorescence microscopy (Collings et al, 2002).…”