Receptor-like proteins in plant immunity: functional regulation and signaling dynamics of tomato Cf proteins

Plant immune receptors are resistance proteins that are essential for recognizing pathogens and activating defense responses in pathogen-resistant plants. This thesis investigates the functional regulation and signaling dynamics of tomato Cf receptor-like proteins (RLPs), which are resistance proteins that are present at the cell surface and recognize specific proteins (so-called effectors) from the fungal pathogen Fulvia fulva. 
Chapter 2 demonstrates that the part of the Cf proteins that is present in the plant cells contributes to the intensity and speed of the resistance response. Chapter 3 shows that codon optimization does not impair Cf-5 immune function but reduces its overall modification by glycosylation. In combination with the viral gene silencing suppressor p19, codon-optimized Cf-5 expression increases but also induces unfolded protein response-related cell death, highlighting the importance of the right receptor biogenesis. Chapter 4 reveals that Cf-4 and Cf-5 use largely conserved immune signaling components but differ in immune dynamics: Cf-4 induces a stronger and faster defense response, whereas Cf-5 triggers a more prolonged response and a broader gene transcriptional reprogramming. Despite these differences, both receptors confer comparable resistance to F. fulva.