Graduation Term

2019

Degree Name

Doctor of Philosophy (PhD)

Department

School of Biological Sciences

Committee Chair

Viktor M. Kirik

Abstract

Regulation of the cortical microtubule cytoskeleton is critical for organized plant cell division. Arabidopsis ton1 and ton2 mutants display random cell division plane placement and lack the plant-specific cortical microtubule array that encircles the nucleus prior to mitosis. In wild type plants, this preprophase band (PPB) of cortical microtubules precisely marks the future division plane. The specific roles of TON1 and TON2 in PPB formation are not yet known. It is suspected that TON1 Recruiting Motif (TRM) proteins may be involved in TON1 and TON2 recruitment to the PPB. Here we describe results for the targeted disruption of a group of TRMs along with localization studies of a larger group of TRMs. We found that TRM33 localizes to the PPB, indicating that it may be important for plant cell division. In addition, TRM13 and TRM14 were found to be important for leaf morphogenesis and trichome cell polarity. Together, these results indicate diverse roles for TRMs in the regulation of the microtubule cytoskeleton and plant development.

The plant cell wall plays an important role in communication, defense, organization and support. Arabidopsis trichomes, or leaf hairs, exhibit distinct cell wall characteristics, including papillae. To better understand the molecular processes important for papillae deposition on the cell wall surface, we identified the genes responsible for the reduction of papillae seen in two glassy hair mutants. Collectively, the presented results show that MED25 and MED16 are necessary for papillae formation on the cell wall surface of leaf trichomes and that a subset of Arabidopsis Mediator tail subunits is required for the transcriptional regulation of papillae promoting genes.

Access Type

Dissertation-Open Access

DOI

http://doi.org/10.30707/ETD2020.Fornero.C

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