Tissue cell polarity throughout leaf development in Arabidopsis thaliana

Mansfield, Catherine (2018) Tissue cell polarity throughout leaf development in Arabidopsis thaliana. Doctoral thesis, University of East Anglia.

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Polarity is a property of many cell types across a multitude of organisms. In multicellular organisms, cell polarity can be coordinated forming tissue-wide polarity fields. Coordinated polarity fields have been described in planar organs in animals, such as the Drosophila wing, and are implicated in transport, growth and differentiation. In plants, coordinated polarity fields have been described across the leaf primordia, and in specific developmental contexts, using PIN proteins. Polarity fields have also been identified in subgroups of leaf epidermal cells later in development, such as in trichomes and the stomatal lineage. However, it is unclear whether coordinated polarity is an underlying feature of planar plant organs. Despite this, predictions have been made that suggest polarity may provide the axial information to guide growth in plants. In this work, I use ectopic expression of the stomatal protein BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL) to reveal a coordinated tissue-wide polarity field that exists throughout Arabidopsis thaliana leaf development. Ectopic BASL localises towards the proximal end of cells and the polarity field revealed diverges in lateral parts of the lamina at later stages of development, suggesting it may be deformed during growth. I show that this polarity field is independent of the stomatal lineage and that cell shape anisotropy is not required for orienting polarity. In addition, I explore mechanisms involved in polarity coordination, and analyse ectopic BASL polarity in relation to PIN polarity at serrations. I show that ectopic BASL polarity mirrors epidermal PIN patterns which suggests a possible common underlying polarity system. Finally, I use a biochemical approach to identify potential novel factors involved in polarity formation in plants. This work provides evidence for tissue-wide polarity in leaves that, like in animals, may provide a general cellular mechanism for guiding growth and differentiation.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Jackie Webb
Date Deposited: 09 Apr 2019 11:49
Last Modified: 30 Apr 2022 00:38
URI: https://ueaeprints.uea.ac.uk/id/eprint/70520

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