Confers resistance to late blight (Phytophthora infestans) races carrying the avirulence gene Avr1. Resistance proteins guard the plant against pathogens that contain an appropriate avirulence protein via an indirect interaction with this avirulence protein. That triggers a defense system including the hypersensitive response, which restricts the pathogen growth. This protein is encoded by the haplotype A genome of the allohexaploid Solanum demissum. Belongs to the disease resistance NB-LRR family.