Plant pathogens convergently evolved to counteract redundant nodes of an NLR immune receptor network
Fig 14
Evolutionary divergent pathogens have evolved to target multiple layers of the Solanaceae NLR network.
P. infestans and G. rostochiensis, 2 evolutionary distinct pathogens, have evolved effectors that suppress signalling mediated by the NRC network. Two effectors from the cyst nematode pathogen, G. rostochiensis (SS10 and SS34), and 1 effector from the blight pathogen, P. infestans (PITG-15278) suppress the function of the NRC4-dependent sensor NLR, Rpi-blb2. The cyst nematode effector, SS15, binds to the NB-ARC domain of both inactive and activated forms of NRC2 and NRC3. By binding the NB-ARC domain of NRC2 and NRC3, SS15 is able to suppress their function. The P. infestans effector, AVRcap1b, suppresses the function of NRC2 and NRC3, and in the case of NRC3, AVRcap1b suppression requires the ESCRT-related protein NbTOL9a. ESCRT, endosomal sorting complex required for transport; ETI/NTI, effector/NLR-triggered immunity; NB-ARC, nucleotide-binding domain shared with APAF-1, various R-proteins, and CED-4; NLR, nucleotide-binding domain and leucine-rich repeat; NRC, NLR required for cell death.