A CNL protein forms an NLR pair with NRCX to modulate plant immunity.

Abstract

Nucleotide-binding leucine-rich repeat (NLR) proteins assemble into genetically linked pairs to mediate effector-triggered immunity (ETI) in plants. Here, we characterize the paired NLRs NRCX and NARY (NRCX adjacent resistance gene Y) in Nicotiana benthamiana. CRISPR/Cas9 knockout of NRCX caused severe dwarfism and constitutively activated immunity, marked by PR1 upregulation and enhanced resistance to Phytophthora capsici. Co-silencing or double knockout of the adjacent NLR NARY partially rescued the nrcx phenotype, revealing NARY as a compensatory regulator that modulates growth and immunity. Structural analysis revealed that NARY harbors non-canonical Walker B and MHD motifs, which lack autoactivation capacity despite their divergence from canonical NLR executors. Split-luciferase and co-immunoprecipitation assays showed that NRCX and NARY interact exclusively through their CC domains, forming a non-canonical regulatory complex. Notably, simultaneous silencing of NRC2/3 and NARY incompletely restored growth in nrcx mutants, implicating additional factors in immune modulation. Our findings establish NARY as a compensatory NLR partner of NRCX that fine-tunes immunity without triggering cell death, revealing a novel mechanism for balancing growth and defense in Solanaceae.