Date of Award

Spring 4-27-2020

Semester of Degree


Document Type

Open Access Thesis

Degree Name

M.S. in Environmental and Forest Biology


Environmental and Forest Biology

Major Professor

William Powell

Steering Committee Member

Christopher Nomura

Steering Committee Member

Susan Anagnost

Steering Committee Member

Stephen Shaw


American chestnut (Castanea dentata) is highly susceptible to a canker disease caused by the invasive fungal pathogen Cryphonectria parasitica. Efforts to restore this tree to its natural range have led to the development of a transgenic American chestnut tree containing an oxalate oxidase (OxO) gene from wheat. The aim of this study was to quantify the OxO protein in our transgenic American chestnut tissues for review by the USDA APHIS BRS, EPA, and FDA federal regulatory agencies and to assess OxO mRNA expression stability in subsequent breeding generations. OxO protein levels were approximately 100-fold greater in chestnuts than found in endogenous cereal sources. Oxalate oxidase mRNA expression levels were stable in the founder Darling 58 transgenic line and its subsequent T1 generation. Expression levels began to fluctuate in some of the T2 generation as our project began to outcross to a more diverse group of mother trees.