Effects of Pseudomonas fluorescens-produced antibiotic 2,4-Diacetylphloroglucinol on Chestnut Blight fungus Cryphonectria parasitica

Bell, Emilie

Effects of Pseudomonas fluorescens-produced antibiotic 2,4-Diacetylphloroglucinol on Chestnut Blight fungus Cryphonectria parasitica

Persistent URL

http://hdl.handle.net/10456/42803

Author(s)

Bell, Emilie

Date Issued

April 3, 2017

Abstract

Before the 1900s, the American chestnut tree, Castanea dentata, was a major component in the United States’ eastern deciduous and hardwood forests. It was a keystone species that many species of animals as well as humans depended on. When the chestnut blight, a fungus called Cryphonectria parasitica, was introduced from China, virtually all American chestnut trees were wiped out. Roots continue to survive in the soil and send up sprouts, but these sprouts do not survive to maturity. Attempts to bring back the chestnut tree have been largely unsuccesful. The purpose of this study was to determine if the root-associated bacteria Pseudomonas fluorescens and the antibiotic it produces, 2,4-diacetylphloroglucinol (DAPG), could be used as an effective treatment against C. parasitica. Chestnut trees were treated with a P. fluorescens inoculum, which was applied directly to cankers. Change in canker size was measured before and after treatment. Antibiosis experiments were performed with P. fluorescens and the P. fluorescens mutant lacking the phlD gene and plugs of C. parasitica in order to see if zones of inhibition were produced. Well diffusion assays were performed with DAPG and C. parasitica to also observe any zones of inhibitions. All treatments were found to be ineffective. Although this method was unsuccessful in treating chestnut blight, it is still important to find a way to restore the American chestnut tree.

Major

Biology

Environmental Science

First Reader(s)

Coenen, Catharina