Date on Master's Thesis/Doctoral Dissertation


Document Type

Master's Thesis

Degree Name




Degree Program

Biology, MS

Committee Chair

Perlin, Michael

Committee Co-Chair (if applicable)

Schultz, David

Committee Member

Schultz, David

Committee Member

Bates, Paula

Author's Keywords

Ustilago; maydis; fungal pathogen; corn smut; pi3k; pten; pathway


Ustilago maydis is a fungal pathogen that is an obligate parasite on Zea mays (Corn) in order to undergo and complete its sexual life cycle. The cells grow as a haploid form until they meet a compatible partner and undergo a dimorphic switch from a budding yeast-like cell type to a filamentous dikaryon. Infection of the host plant is characterized by leaf chlorosis, anthocyanin content, and formation of large galls that develop on the stem, leaves, cobs, and flowers. Many signaling cascades such as MAPK and PKA are involved in the regulation of the infection lifecycle. The Phosphatidylinosotiol 3 Kinase/ Phosphatase and tensin homolog pathway (PI3K/PTEN ) is known to heavily influence cell growth, survival, proliferation, and various other cell cycle regulation events. The roles of the PI3K/PTEN pathway has not been explored in U. maydis. Altering candidate genes for PI3K and PTEN in U. maydis may provide insight into their function and roles in regards to pathogenicity and cell survival. Mating, cell viability, and infection assays were performed in order to determine the roles of the candidate genes functioning on pathogenicity. Disrupting or overexpressing these genes appears to have no effect on pathogenicity, survival, morphology, and proliferation.