Involved in plant defense. Confers resistance to the fungal pathogen C.fulvum through recognition of the AVR9 elicitor protein. Interacts with thioredoxin-like protein CITRX. Induced by C.fulvum AVR9 elicitor protein in a temperature-sensitive manner. Repressed by sly-miR6022. The extracellular leucine-rich repeats are required for the specificity of the elicitor protein recognition. Important sequence determinants of Cf-9 function are located in LRRs 10 to 18. Belongs to the RLP family. The article has been retracted, because it has become clear that the thioredoxin that interacts in yeast 2-hybrid with the Cf-9 C-terminus is in fact localized in the chloroplast, rendering a role in Cf-9 signaling unlikely. All the authors agree that this paper should be withdrawn from the scientific literature.