CORTICAL MICROTUBULE DISORDERING1 Is Required for Secondary Cell Wall Patterning in Xylem Vessels

Abstract

Proper patterning of the cell wall is essential for plant cell development. Cortical microtubule arrays direct the deposition patterns of cell walls at the plasma membrane. However, the precise mechanism underlying cortical microtubule organization is not well understood. Here, we show that a microtubule-associated protein, CORD1 (CORTICAL MICROTUBULE DISORDERING1), is required for the pitted secondary cell wall pattern of metaxylem vessels in Loss of and its paralog, , led to the formation of irregular secondary cell walls with small pits in metaxylem vessels, while overexpressing led to the formation of abnormally enlarged secondary cell wall pits. Ectopic expression of disturbed the parallel cortical microtubule array by promoting the detachment of microtubules from the plasma membrane. A reconstructiveapproach revealed that CORD1-induced disorganization of cortical microtubules impairs the boundaries of plasma membrane domains of active ROP11 GTPase, which govern pit formation. Our data suggest that CORD1 promotes cortical microtubule disorganization to regulate secondary cell wall pit formation. The Arabidopsis genome has six paralogs that are expressed in various tissues during plant development, suggesting they are important for regulating cortical microtubules during plant development.

Wood and water: How trees modify wood development to cope with drought

“…Recent destined to become pits (Oda & Fukuda, 2013;Oda, Iida, Kondo, & Fukuda, 2010;Sasaki, Fukuda, & Oda, 2017 formation has features consistent with a classical Turing reactiondiffusion mechanism (Nagashima et al, 2018).…”

“…Deposition of cellulose microfibrils in secondary cell walls is directed by a plasma membrane‐localized cellulose synthase complexes that track microtubules. Protein complexes containing MICROTUBULE DEPLETION DOMAIN1 (MIDD1) and RHO‐RELATED PROTEIN FROM PLANTS11 (ROP11) actively promote the disassembly of cortical microtubules and thus exclude cellulose synthase complexes and secondary cell wall formation in regions destined to become pits (Oda & Fukuda, ; Oda, Iida, Kondo, & Fukuda, ; Sasaki, Fukuda, & Oda, ). Interestingly, mutation or changes in expression of these and MIDD1/ROP11 interacting proteins can dramatically change the spacing and size of pits (Nagashima et al, ).…”

Identification and characterization of the land-plant-specific microtubule nucleation factor MACET4

“…A member of the MACET gene family, MACET1 (also known as CORD1), has been recently reported to play a role in the destabilization of cortical microtubules during formation of pits in the wall of xylem cells (Sasaki et al, 2017). The mechanism for microtubule destabilization by CORD1/MACET1 was proposed to be through inhibition of interaction between microtubules and the plasma membrane.…”

The Cytoskeleton and Its Role in Determining Cellulose Microfibril Angle in Secondary Cell Walls of Woody Tree Species

“…Simultaneously, cell wall growth is promoted at pit boundaries through the ROP-BDR-WAL-actin pathway allowing for precise control of bordered pit formation [73]. In addition, Cortical Microtubule Disordering Protein 1 (CORD1) affects microtubule organisation, branching angle and microtubule attachment to the plasma membrane, resulting in abnormally enlarged SCW pits [74]. Other MAPs belonging to MAP20 and MAP70 families were also suggested to play a role in cellulose synthesis and SCW patterning in xylem cells [75,76].…”