Cell cortex microtubules contribute to division plane positioning during telophase in maize

Abstract

The phragmoplast is a plant-specific microtubule and microfilament structure that forms during telophase to direct new cell wall formation. The phragmoplast expands towards a specific location at the cell cortex called the division site. How the phragmoplast accurately reaches the division site is currently unknown. We show that a previously uncharacterized microtubule arrays accumulated at the cell cortex. These microtubules were organized by transient interactions with division-site localized proteins and were then incorporated into the phragmoplast to guide it towards the division site. A phragmoplast-guidance defective mutant, tangled1, had aberrant cortical-telophase microtubule accumulation that correlated with phragmoplast positioning defects. Division-site localized proteins may promote proper division plane positioning by organizing the cortical-telophase microtubule array to guide the phragmoplast to the division site during plant cell division.One Sentence SummaryMicrotubules accumulate at the cell cortex and interact with the plant division machinery to direct its movement towards the division site.

The localization of PHRAGMOPLAST ORIENTING KINESIN1 at the division site depends on two microtubule binding proteins TANGLED1 and AUXIN-INDUCED-IN-ROOT-CULTURES9 in Arabidopsis

“…TAN1 bundles and crosslinks microtubules in vitro (Martinez et al, 2020). In vivo, TAN1 promotes microtubule pausing at the division site (Bellinger et al, 2021). TAN1, together with other division site localized proteins, is critical for the organization of an array of cell cortex localized microtubules that is independent from the phragmoplast.…”

“…TAN1, together with other division site localized proteins, is critical for the organization of an array of cell cortex localized microtubules that is independent from the phragmoplast. These cortical-telophase microtubules accumulate at the cell cortex during telophase and are subsequently incorporated into the phragmoplast to direct its movement towards the division site (Bellinger et al, 2021). Other important division site localized proteins were identified through their interaction with TAN1, such as the division site localized kinesin-12 proteins PHRAGMOPLAST ORIENTING KINESIN1 (POK1) and POK2 (Müller et al, 2006; Lipka et al, 2014).…”

The OPAQUE1/DISCORDIA2 myosin XI is required for phragmoplast guidance during asymmetric cell division in maize

“…The TAN1 interacting partners PHRAGMOPLAST ORIENTING KINESIN1 (POK1) and POK2 are kinesin proteins that also mark the division site (27)(28)(29). Both POK and TAN also localize to the phragmoplast (28,(30)(31)(32).…”

Action at a distance: Defects in division plane positioning in the root meristematic zone affect cell organization in the differentiation zone

“…TAN1 bundles and crosslinks microtubules in vitro (Martinez et al, 2020). In vivo, TAN1 promotes microtubule pausing at the division site (Bellinger et al, 2021). Critically, TAN1, together with other division site localized proteins, organizes an array of cell cortex localized microtubules that is independent from the phragmoplast.…”

“…Critically, TAN1, together with other division site localized proteins, organizes an array of cell cortex localized microtubules that is independent from the phragmoplast. These cortical-telophase microtubules accumulate at the cell cortex during telophase and are subsequently incorporated into the phragmoplast to direct its movement towards the division site (Bellinger et al, 2021). Other important division site localized proteins were identified through their interaction with TAN1, such as the kinesin-12 protein PHRAGMOPLAST ORIENTING KINESIN1 (POK1) and POK2 (Müller et al, 2006), (Lipka et al, 2014).…”