Studies on plant immunity: dissection of the Cf-4/SOBIR1-containing complex in Nicotiana benthamiana

Summary

Plants have an innate immune system that is organised into two tiers: one at the surface of the cells and the other in the cell’s cytoplasm. Cell-surface receptors are involved in the first line of defence, triggering immune responses upon the perception of immunogenic patterns that are produced during invasion of the pathogen. The tomato cell-surface receptor Cf-4 requires the co-receptor SOBIR1 and confers resistance to strains of the fungal pathogen Cladosporium fulvum secreting the matching effector protein Avr4, triggering an immune response that includes a form of programmed cell death, referred to as the hypersensitive response (HR). This thesis explores the early signalling events triggered by the cell-surface receptor Cf-4, using the solanaceous model plant Nicotiana benthamiana. This thesis introduces a novel method to visualise and quantify the intensity of the HR. The thesis furthermore transfers insight from the immune signalling taking place in Arabidopsis to solanaceous plants  and introduces the use of proximity-dependent labelling, revealing the proximal proteome of the Cf-4/SOBIR1-containing receptor complex in N. benthamiana.