Dong Xiaohua, Zhang Xiaoyan, Lu Xu, Yang Yufeng, Xia Chuyan, Pan Weiye, Yin Zhiyuan, Zhao Yaning, Ai Gan, Dou Daolong
College of Plant Protection, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing, China.
Stress Biol. 2025 Sep 3;5(1):55. doi: 10.1007/s44154-025-00245-6.
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.
核苷酸结合富含亮氨酸重复序列（NLR）蛋白组装成遗传连锁对，以介导植物中的效应子触发免疫（ETI）。在此，我们对本氏烟草中的配对NLRs NRCX和NARY（NRCX相邻抗性基因Y）进行了表征。NRCX的CRISPR/Cas9敲除导致严重矮化并组成型激活免疫，其特征为PR1上调以及对辣椒疫霉的抗性增强。相邻NLR NARY的共沉默或双敲除部分挽救了nrcx表型，表明NARY是一种调节生长和免疫的补偿性调节因子。结构分析表明，NARY含有非典型的沃克B和MHD基序，尽管它们与典型的NLR执行元件不同，但缺乏自激活能力。分裂荧光素酶和免疫共沉淀分析表明，NRCX和NARY仅通过它们的CC结构域相互作用，形成一种非典型的调节复合物。值得注意的是，NRC2/3和NARY的同时沉默并未完全恢复nrcx突变体的生长，这表明免疫调节中存在其他因素。我们的研究结果表明，NARY是NRCX的补偿性NLR伴侣，可微调免疫而不触发细胞死亡，揭示了茄科植物平衡生长和防御的新机制。
