Plant cell division from the perspective of polarity

Abstract

The orientation of cell division is a major determinant of plant morphogenesis. In spite of considerable efforts over the past decades, the precise mechanism of division plane selection remains elusive. The majority of studies on the topic have addressed division orientation from a predominantly developmental or a cell biological perspective, respectively. Thus, mechanistic insights into the links between developmental and cellular factors affecting division orientation are particularly lacking. Here, I review recent progress in the understanding of cell division orientation in the embryo and primary root meristem of Arabidopsis from both developmental and cell biological standpoints. I offer a view of multilevel polarity as a central aspect of cell division: On the one hand, the division plane is a readout of tissue- and organism-wide polarities; on the other hand, the cortical division zone can be seen as a transient polar subcellular plasma membrane domain. I argue that a polarity-focused conceptual framework and the integration of developmental and cell biological approaches hold a great promise to unravel the mechanistic basis of plant cell division orientation in the near future.

A precise balance of TETRASPANIN1/TORNADO2 activity is required for vascular proliferation and ground tissue patterning in Arabidopsis

“…With this rationale, we transcriptionally profiled the p RPS5A::DOF2.1-GR inducible misexpression line (Smet et al, 2019) in a time-course induction using bulk RNA-seq ( Table S1 ) and overlapped the transcripts upregulated upon DOF2.1 induction with the phloem/procambium-enriched candidates obtained from the scRNA-seq dataset (Wendrich et al, 2020) ( Table S1 , Figure 1A ). To further narrow down the search space, we focused on genes linked to entities involved in the execution of cell division, such as the cytoskeleton, plasma membrane or the cell wall (Glanc, 2022; Livanos and Müller, 2019). Among the shortlist of candidate genes identified by this approach, TETRASPANIN1/ TORNADO2 (TET1/TRN2) drew our attention for several reasons.…”

“…Thirdly and most important, TET proteins are conserved across multicellular eukaryotes and function as molecular scaffolds in a plethora of multiprotein complexes at the plasma membrane in animal cells (Reimann et al, 2017; Termini and Gillette, 2017). As protein scaffolding is a common feature of numerous cellular polarity establishment pathways (Ramalho et al, 2021), this provides a mechanistically plausible role for TET1 in plant cell division orientation, which is thought to be tightly linked to cell polarity (Glanc, 2022; Müller, 2019). In summary, based on overlap analysis of two different transcriptomic datasets, we selected TET1 as a putative regulator of cell division orientation during vascular development.…”

“…A major unanswered question at the interface of plant cell and developmental biology is how tissue and cell polarity cues are integrated into precisely positioning the cell division plane (Glanc, 2022). In order to find novel regulators of this process in the context of developing vascular cells of the Arabidopsis root, we took a transcriptomics approach to pinpoint those factors being expressed at the correct spatiotemporal location.…”

“…Division plane formation is often viewed as a transient polarization event and is as such expected to depend on similar mechanisms as other polarity establishment pathways (Glanc, 2022; Müller, 2019). Cell polarization in plant and non-plant systems typically involves positive feedback loops that mechanistically rely on protein scaffolding (Chiou et al, 2017; Ramalho et al, 2021).…”

A precise balance of TETRASPANIN1/TORNADO2 activity is required for vascular proliferation and ground tissue patterning in Arabidopsis

“…Division plane formation is often viewed as a transient polarisation event and is, as such, expected to depend on mechanisms similar to those of other polarity establishment pathways (Glanc, 2022; Müller, 2019). Cell polarisation in plant and non‐plant systems typically involves positive feedback loops that mechanistically rely on protein scaffolding (Chiou et al, 2017; Ramalho et al, 2022).…”