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Date Permissions Signed


Date of Award


Document Type

Masters Thesis

Degree Name

Master of Science (MS)



First Advisor

Pillitteri, Lynn

Second Advisor

Singh-Cundy, Anu

Third Advisor

Leaf, David Scott, 1955-


Stomata are epidermal pores on land plants that exchange gases to maintain water potential and photosynthesis. Two guard cells flank each pore and change the aperture based on turgor pressure-induced changes in their shape. Stomatal aperture and density are affected by environmental stimuli such as light quality and quantity, CO2 concentrations, and water availability. The basic helix-loop-helix (bHLH) transcription factor MUTE drives the differentiation of transient epidermal stem cells, called meristemoids, to guard mother cells, which divide to form a mature stoma. MUTE is only transcriptionally active in late-stage meristemoids, but the mechanisms controlling its expression are unknown. The purpose of this study was to determine the region of the MUTE promoter is required for transcription then identify proteins that interact with that region. Promoter deletion studies found a 57 bp fragment required for promoter activity. Mass spectrometry identified 295 proteins that bound the 57 bp fragment in vitro and five were chosen for phenotypic analysis of their null mutants. One of the chosen mutants, los2, T-DNA-insertion mutagenized plants showed a sterile, dwarfed phenotype and had clusters of 2-3 stomata. These results shed insight into nature of MUTE regulation and allow for more precise studies of the proteins and DNA elements involved.





Western Washington University

OCLC Number


Subject – LCSH

Stomata--Genetics; Promoters (Genetics); Mutagenesis; Plant proteins; Gene expression




masters theses




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