Supervisor: TÜ MRI dotsent Andres Mäe.
Opponent: Vanemteadur Guy Condemine, Prantsusmaa Rahvuslik Teadusuuringute Keskus (CNRS), Lyon, Prantsusmaa
We feel hunger by rumbling in our stomach. We become restless, and soon set our way to grocery to fight the hunger. Although bacteria are more than million times smaller than we are, they are also able to feel the presence or absence of food resources and react accordingly. The object of my research is a bacterium belonging to the group called Pectobacterium. It eats plants, including those we use for food, such as potato tubers and carrots. Infected vegetables turn rapidly into inedible watery mass reducing quality and amount of our food. The question raised in my thesis is what genes in this bacterium determine whether or not pathogen attacks plants. I discovered a domino effect that is induced using special sensors located near cell surface and spreads inside the bacterium. Different proteins influence each other causing large rearrangements inside the cell. The induced change is also expressed in bacterium's behaviour: it becomes sessile and stops producing proteins required for plant attack. It becomes harmless. My work has greatly contributed to identification of the players involved in this chain reaction, but how this system is induced is still unknown. Finding the induction mechanism may be a key in saving our food from bacterial destruction.