Regulation of arabidopsis stomatal development and patterning by the AGCVIII kinase family
Abstract/Contents
- Abstract
- With multicellularity has come additional capacity for cells to become functionally and structurally diverse; along with diversity comes a need for organization and patterning. The formation of distinct cell types is often linked to asymmetric cell divisions (ACDs) in which a cell divides to create daughters that differ in size, composition, proximity to signaling sources, and ultimately fate. Cortical cell polarity is an important feature of ACDs. In animal cells, the PAR proteins play an important role in establishing cortical polarity driving ACDs and axis formation, but they are conspicuously absent from plant genomes. Interestingly, we see the conservation of mechanistic logic cells used to build polarity complexes. For example, AGC kinases enforce or reinforce cell polarity in plants, animals, and fungi. The stomatal lineage of Arabidopsis thaliana presents us with a unique opportunity to understand how cell polarity and orchestrated cell divisions contribute to a robust developmental plan. Core to this process are the cortically polarized scaffolding proteins BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL) and the BREVIS RADIX family (BRXf). These novel, plant-specific proteins are required to ensure proper asymmetric divisions in stomatal lineage cells. Loss of BASL results in more symmetric divisions and an over-proliferation of epidermal cells of mixed identity. To further elucidate BASL/BRXf's ability to confer ACD competency to stomatal lineage cells, we, in collaboration with proteomics specialist Geert De Jager (VIB Belgium), did a protein interaction screen that yielded several interaction partners for BRXL2. Among the candidates identified in the assay were members of the plant-specific PIN-FORMED (PINs) family and members of the AGCVIII kinase family. In this thesis, I present genetic and cell biological data that support a novel role for the AGCVIII kinase D6PK in facilitating asymmetric cell division and asymmetric fate acquisition in the stomatal lineages through the BASL and BRXL2. D6PK is broadly expressed in the leaf and is present in stomatal lineage cells, mature pavement cells, and guard cells. Furthermore, D6PK is localized to the BASL/BRXf polarity complex in the stomatal lineage. Its polarization mirrors BASL and BRX proteins during asymmetric cell division in that the D6PK polar crescent is inherited by the larger daughter cell. Further, we show that D6PK is required for patterning stomata. Stomatal lineage cells in the d6pk012 triple mutant background divided excessively and occasionally acquired identical fates, resulting in paired guard cells. Known transcriptional regulators are also disrupted in d6pk012. Due to the nature of the phenotype, we speculated that D6PK might be a core member of the BASL/BRXf polarity complex or a regulator of polarity. D6PK and BASL polarity are mutually dependent, while D6PK maintained some ability to polarize in the brxq background. The appendix of this thesis explores D6PKs' relationship with cell signaling factors, additional interactors of BRXL2, and automated cell segmentation.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2024; ©2024 |
| Publication date | 2024; 2024 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Spencer, Dirk Junior Jamal |
|---|---|
| Degree supervisor | Bergmann, Dominique |
| Thesis advisor | Bergmann, Dominique |
| Thesis advisor | Feldman, Jessica L |
| Thesis advisor | Shapiro, Lucy |
| Degree committee member | Feldman, Jessica L |
| Degree committee member | Shapiro, Lucy |
| Associated with | Stanford University, School of Humanities and Sciences |
| Associated with | Stanford University, Department of Biology |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Dirk Junior Jamal Spencer. |
|---|---|
| Note | Submitted to the Department of Biology. |
| Thesis | Thesis Ph.D. Stanford University 2024. |
| Location | https://purl.stanford.edu/kq100kz3466 |
Access conditions
- Copyright
- © 2024 by Dirk Junior Jamal Spencer
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...