Ethylene response and phytohormone-mediated regulation of gene expression in Komagataeibacter xylinus ATCC 53582

Komagataeibacter xylinus ATCC 53582 is a fruit-associated, cellulose-producing bacterium that responds to and synthesizes phytohormones. This thesis elaborates on the ecophysiology of K. xylinus. Responses to indole-3-acetic acid (IAA), abscisic acid (ABA) and ethylene, produced in situ from ethephon, were of particular focus. The effect of these phytohormones on K. xylinus cellulose production and expression of cellulose biosynthesis-related genes (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx) were determined using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR), respectively. Ethylene enhanced cellulose yield by upregulating bcsA and bcsB expression, while IAA decreased cellulose yield by downregulating bcsA. Differential gene expression within the bacterial cellulose synthesis (bcs) operon is reported and a phytohormone-regulated CRP/FNR transcription factor was identified that may influence K. xylinus cellulose biosynthesis. Based on evidence provided in this thesis, the classification of K. xylinus as a saprophyte and its potential to accelerate fruit ripening in nature is proposed.

Name thesis:degree_name

Master of Science (MSc)

Discipline thesis:degree_discipline

Applied Bioscience

Grantor

University of Ontario Institute of Technology

Year dc:date.issued

2016

Author dc:creator

• Augimeri, Richard Vincent

Advisor dc:contributor.advisor

• Strap, Janice

• Komagataeibacter xylinus
• Bacterial cellulose
• Plant-microbe interactions
• Ethephon
• Ethylene

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10155/660

OAI identifier oai:identifier

oai:ontariotechu.scholaris.ca:10155/660