Resistance breaking isolates of the Tomato spotted wilt virus (TSWV) were found in the ‘resistant’ pepper (Capsicum annuum) field.
I started by identifying which viral protein was able to induce the resistance in the pepper plants (Chapter 2). In the next chapter (3), I investigated whether the ability to induce resistance was functionally linked to its other known function, which could be uncoupled. In a next study, I looked into a possible interaction of this viral protein with a host protein from pepper, which was thought to play a role in the resistance response (Chapter 4). In the last experimental chapter (5), I could show that the resistance in the plant was temperature sensitive, but the virus isolates themselves also showed a temperature dependent resistance response. Additionally, I designed a diagnostic tool to be able to differentiate between different isolates in the field, related to the resistance. Chapter 1 is a review, describing the antiviral resistance genes in all plants known, including a comparison to the animal immune system. The general discussion chapter (6), summarizes the data in a model that could explain the resistance mechanism.