PhD defence: Daniel Vik
PhD Candidate
Daniel Vik
Title of PhD Thesis
Quantitative aspects and dynamic modelling of glucosinolate metabolism
Abstract
The presented thesis is a collection of scientific manuscripts describing various aspects of glucosinolate metabolism. Glucosinolates are chemical defense compounds found in certain plants such as broccoli, mustard and kale. Their primary role is to defend the plant against attack by insects or disease. Glucosinolates are converted into different kinds of highly reactive compounds, some of them being really nasty and thereby scaring off enemies of the plant. Understanding the way the plant produce and degrade glucosinolates is important for our broader understanding of how plants interact with dangers such as insects and diseases, and it has implications for developments in agriculture and medicine.
In this thesis I present the implementation of a new technology platform that makes it possible to measure the levels of the individual enzymes responsible for glucosinolate production. I use this technology to compare several genetic mutants and the effects of hormone treatment. The results show that mRNA reflects the enzyme levels accurately across mutants, but that the enzyme levels are not accurately reflected in the mRNA levels upon hormone treatment. These findings would suggest that the enzyme levels are somehow regulated by currently unknown mechanisms.
To try to find out what these possible mechanisms could be, my colleagues and I examined the physical interactions of glucosinolate producing enzymes. We combined two complementary large-scale genomics approaches to search for proteins that would interact with the glucosinolate enzymes. Our findings show that the enzymes of glucosinolate production interact with proteins that are involved in broader physiological processes. In addition, I examined the role of a small protein which based on genetic expression data would appear to be linked to glucosinolate biosynthesis.
Finally, I constructed a mathematical model describing the degradation of glucosinolates, and how the degradation of one particular glucosinolate could influence plant growth and defense by manipulating a central growth hormone.
Supervisor
Professor Barbara Ann Halkier and Associate Professor Meike Burow, DynaMo Center, University of Copenhagen
Assessment Committee
Daniele Werck, Universite de Strabourg
Alexa Jones, University of Warwick
Mathias Pribil, PLEN
Reception
The defence will be followed by a reception at Thorvaldsensvej 40, room H117
