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Poster

Session: Session 1 Presenting Authors at Posters (Evens)

P-004 - A singleton rice NLR recognises multiple blast pathogen effectors of the KP6 structural family

Tuesday, July 15, 2025
09:55 - 11:30  
Location: Confex Hall 3
Extracellular & Intracellular non-self recognition & signaling

Blast is a devastating disease of cereal crops caused by the fungus Magnaporthe oryzae. The singleton CC-type nucleotide-binding, leucine-rich repeat (NLR) rice immune receptor KRN (KP6 Recognising NLR) recognises two wheat blast pathogen effectors, eTO16 and eTO31. Engineering KRN expression in wheat has potential as a novel source of resistance to wheat blast. Here, we investigate the molecular mechanisms underpinning KRN-mediated response to these effectors. Using the heterologous system Nicotiana benthamiana, we have shown the specific recognition of eTO16 and eTO31 by KRN leading to cell death, recapitulating the resistance seen in rice. KRN requires a native, intact N-terminal MADA motif, and NB-ARC P-loop and MHD-like motifs to trigger immune responses. During activation, KRN oligomerises from an inactive dimer to an active, higher order complex. Furthermore, through structure determination by X-ray crystallography we have shown eTO16 and eTO31 belong to the large and highly conserved Killer Protein 6 (KP6) structural effector family, despite limited sequence conservation. Moreover, using N. benthamiana, we showed KRN responds to another KP6 effector from Colletotrichum obiculare, co KP6. We therefore hypothesise KRN is a singleton NLR capable of recognising a range of KP6 effectors, which could offer novel sources of resistance to multiple pathogens.