Breaking restricted taxonomic functionality by dual resistance genes.

NB-LRR-type disease resistance (R) genes have been used in traditional breeding programs for crop protection. However, functional transfer of NB-LRR-type R genes to plants in taxonomically distinct families to establish pathogen resistance has not been successful. Here we demonstrate that a pair of Arabidopsis (Brassicaceae) NB-LRR-type R genes, RPS4 and RRS1, properly function in two other Brassicaceae, Brassica rapa and B. napus, but also in two Solanaceae, Nicotiana benthamiana and tomato (Solanum lycopersicum). The solanaceous plants transformed with RPS4/RRS1 confer bacterial effector-specific immunity responses. Furthermore, RPS4 and RRS1, which confer resistance to a fungal pathogen Colletotrichum higginsianum in Brassicaceae, also protect against Colletotrichum orbiculare in cucumber (Cucurbitaceae). Thus the successful transfer of two R genes at the family level overcomes restricted taxonomic functionality. This implies that the downstream components of R genes must be highly conserved and interfamily utilization of R genes can be a powerful strategy to combat pathogens.