THE FEEDBACK BETWEEN CELL SHAPE AND CYTOSKELETAL DYNAMICS ON CELL DIVISION AND EXPANSION IN EPIDERMAL PAVEMENT CELLS OF ARABIDOPSIS

The epidermal layer of Arabidopsis thaliana (L.) Heynh. leaves plays a critical role in tissue formation, particularly through the development of lobes in the anticlinal walls of pavement cells, though curvature is also noted in the periclinal walls. The epidermal pavement cells form unique lobed shapes over time, while stomata, composed of guard cells, are identical in size and shape. Both cell types emerge from the same precursor cells and are produced through highly regulated divisions based on the morphology of the parent cell. Specifically, asymmetric divisions within the epidermis initiate stomatal lineages, where all divisions, excluding the terminal division, are asymmetric. Mutant lines with altered gene expression were selected based on phenotypes exhibiting altered cell division, expansion, and generation of specialized cells were used to evaluate hypotheses regarding sidewall curvature, mother cell bisection, and cell-division frequency. The pre-prophase band (PPB) microtubule array predicts the future division sites. This study explored a potential feedback loop between cell division and shape in Arabidopsis pavement cells, where lobes in the anticlinal cell wall curve towards the cell center, forming narrow regions that are hotspots for new cell divisions. In these divisions, the other cell area and intercepted sidewall segments were often bisected asymmetrically. Persistent microtubule bands at these sites can develop into PPBs, driving new cell wall formation and enhancing existing sidewall curvature. My research aims to determine how these lobes influence division sites and contribute to my understanding of the cytoskeletal regulation of cell division and expansion within the epidermal layer. My thesis focused on the development of the epidermal layer in Arabidopsis thaliana, emphasizing division orientation and microtubule activity in the epidermis.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Biology

Grantor

University of Saskatchewan

Year dc:date.issued

2025

Author dc:creator

• McEvoy, Delanie

Advisor dc:contributor.advisor

• Ambrose, Chris

Committee members dc:contributor.committeemember

• Wei, Yangdou
• Wilson, Ken
• Wang, Hong
• Webster, Nicole
• Benson, James

• Arabidopsis
• pavement cells
• epidermis
• microtubules
• cell wall morphology

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10388/17266

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/17266