What we expect you to know
You should know, what these terms mean and you should be able to explain them in your own words.
Malthus . Kropotkin . coevolution . parasitism . symbiosis . Lotka-Volterra equations . necrotrophic . biotrophic . root nodules . mycorriza . hypersensitive response (HR) . gene-for-gene hypothesis . elicitors . virulence genes . avirulence genes . PTI (PAMP-triggered immunity). effector-triggered immunity (ETI) . volatiles . terpenoids . flavonoids . stilbenes . Downy Mildew . Powdery Mildew . chemotaxis
05 Coevolution of Plants with Pathogens: Exercise
1. Bees are highly cooperative - even to the level of sacrificing their life for the bee state, when they sting an invader and die. There is a genetic reason that favoured the rapid evolution of cooperativity in bees. Do you know, which one?
2. A lab in Israel wanted to generate tomatoes with a high level of monoterpenes by overexpression of geraniol synthase, the key enzyme, where the monoterpene pathway branches from the general isoprenoid pathway. The approach was successful, the tomatoes had a nice aromatic smell like lemons, but they did not turn red, but only orange. Can you explain this?
3. Biotrophic pathogens have evolved effectors to overcome PTI. Why did the more simple possibility that pathogens loose the PAMPs triggering PTI not evolve?
4. A study using the molecular marker internally transcribed spacer 1 (its1) was conducted to analyse the genetic diversity of Plasmopara viticola in different regions of the world: A. East of the USA (the region of origin), B. France, C. China, D. Chile, E. South Africa. What is your prediction about the level of genetic diversity in these five regions?
5. The desamination of phenylalanine by the enzyme phenylalanine ammonium lyase is the starting point for three central secondary metabolic pathways in plants giving rise to lignins (1), flavonoids and anthocyanines (2), and stilbenes (3). Explain, in which order these pathways must have evolved (you have to apply knowledge from the second lecture to solve this task).