University of Western Ontario - Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Biology

Supervisor

Dr. Lining Tian

Abstract

To achieve high yields, corn fields are supplemented with nitrogen fertilizers. Nitrogen fertilizers account for a significant portion of production costs, and are harmful to the environment. Gluconacetobacter diazotrophicus, an endophytic nitrogen-fixing bacterium supplies its natural host sugarcane with a significant amount of nitrogen. This study investigated the colonization of G. diazotrophicus in seven different corn genotypes consisting of sweet and grain corn via three different methods of inoculation: soil drench, root dip, and aseptic inoculation. Sucrose content of the corn genotypes and nitrogenase activity were also analysed. Colonization was confirmed by PCR analysis. G. diazotrophicus colonization was detected using the aseptic method of inoculation, in which colonization efficiency ranged from 90-100%. Sucrose concentrations did not appear to play a role in colonization efficiency. This research is an important step towards the utilization of this bacterium for nitrogen fixation in corn.