9RIA

Cryo-EM structure of tomato NRC3-AVRcap1b complex

Summary for 9RIA

• Entry DOI: 10.2210/pdb9ria/pdb
• EMDB information: 53991
• Descriptor: NRC3, RxLR effector protein PITG_16705, ADENOSINE-5'-TRIPHOSPHATE (3 entities in total)
• Functional Keywords: effector, nlr, plant immunity, resistosome, immune system
• Biological source: Solanum lycopersicum (tomato); More
• Total number of polymer chains: 4
• Total formula weight: 393951.83

Authors

Seager, B.A.,Kamoun, S.,Madhuprakash, J. (deposition date: 2025-06-11, release date: 2025-07-23, Last modification date: 2026-06-17)

Primary citation

Seager, B.A.,Harant, A.,Contreras, M.P.,Hou, L.Y.,Wu, C.H.,Kamoun, S.,Madhuprakash, J.
A plant pathogen effector blocks stepwise assembly of a helper NLR resistosome.
Sci Adv, 12:eaeb1931-eaeb1931, 2026

PubMed Abstract: Helper NLRs function as central nodes in plant immune networks. Upon activation, they oligomerize into inflammasome-like resistosomes to initiate immune signaling, yet the dynamics of resistosome assembly remain poorly understood. Here, we show that the virulence effector AVRcap1b from the Irish potato famine pathogen suppresses immune activation by directly engaging oligomerization intermediates of the tomato helper NLR SlNRC3. Cryo-EM structures of SlNRC3 in AVRcap1b-bound and unbound states reveal that AVRcap1b bridges multiple protomers, stabilizing a stalled intermediate and preventing formation of a functional resistosome. Leveraging AVRcap1b as a molecular tool, we also capture an additional SlNRC3 resistosome intermediate showing that assembly proceeds in a stepwise manner from dissociated monomers. These findings uncover a previously unrecognized vulnerability in NLR activation and reveal a pathogen strategy that disrupts immune complex assembly. This work advances mechanistic understanding of resistosome formation and uncovers a previously unrecognized facet of pathogen-plant coevolution.

PubMed: 42247517
DOI: 10.1126/sciadv.aeb1931

Experimental method

ELECTRON MICROSCOPY (3.2 Å)