Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, Canberra, ACT 2601, Australia.
Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia.
Essays Biochem. 2022 Sep 30;66(5):471-483. doi: 10.1042/EBC20210072.
Plants deploy extracellular and intracellular immune receptors to sense and restrict pathogen attacks. Rapidly evolving pathogen effectors play crucial roles in suppressing plant immunity but are also monitored by intracellular nucleotide-binding, leucine-rich repeat immune receptors (NLRs), leading to effector-triggered immunity (ETI). Here, we review how NLRs recognize effectors with a focus on direct interactions and summarize recent research findings on the signalling functions of NLRs. Coiled-coil (CC)-type NLR proteins execute immune responses by oligomerizing to form membrane-penetrating ion channels after effector recognition. Some CC-NLRs function in sensor-helper networks with the sensor NLR triggering oligomerization of the helper NLR. Toll/interleukin-1 receptor (TIR)-type NLR proteins possess catalytic activities that are activated upon effector recognition-induced oligomerization. Small molecules produced by TIR activity are detected by additional signalling partners of the EDS1 lipase-like family (enhanced disease susceptibility 1), leading to activation of helper NLRs that trigger the defense response.
植物利用细胞外和细胞内免疫受体来感知和限制病原体的攻击。快速进化的病原体效应子在抑制植物免疫方面起着至关重要的作用，但也被细胞内核苷酸结合、富含亮氨酸重复的免疫受体 (NLRs) 监测，从而导致效应子触发的免疫 (ETI)。在这里，我们回顾了 NLR 如何识别效应子，重点关注直接相互作用，并总结了 NLR 信号功能的最新研究发现。卷曲螺旋 (CC)-型 NLR 蛋白通过在识别效应子后寡聚化形成穿透细胞膜的离子通道来执行免疫反应。一些 CC-NLR 与传感器 NLR 触发辅助 NLR 寡聚化的传感器辅助网络一起发挥作用。Toll/白细胞介素-1 受体 (TIR)-型 NLR 蛋白具有催化活性，在识别诱导的寡聚化后被激活。TIR 活性产生的小分子被增强疾病易感性 1 (EDS1) 类脂酶样家族的其他信号伙伴检测，导致辅助 NLR 的激活，从而触发防御反应。
