加拿大英属哥伦比亚大学Yuelin Zhang、Xin Li等研究人员合作发现，TIR信号的激活促进模式触发的免疫。2021年9月20日，国际知名学术期刊《自然》在线发表了这一成果。

据研究人员介绍，植物免疫反应主要由两种类型的受体激活。质膜定位的模式识别受体（PRR）感知细胞外的微生物特征，而核苷酸结合的亮氨酸富集重复受体（NLR）识别来自病原体的细胞内效应蛋白。拥有N端Toll/白细胞介素-1受体（TIR）结构域的NLR通过TIR结构域的NAD酶活性激活防御反应。

研究人员发现，TIR信号的激活在PRR介导的模式触发免疫（PTI）中起着关键作用。TIR信号突变体表现出PTI反应减弱，对病原体的抵抗力下降。一致的是，在NLR水平降低的植物中，PTI受到损害。用PTI诱导剂flg22或nlp20处理可以迅速诱导许多编码TIR结构域蛋白的基因，这可能是在PTI期间激活TIR信号的原因。总的来说，这项研究显示，TIR信号的激活是在PTI期间促进植物防御的一个重要机制。

附：英文原文

Title: Activation of TIR signalling boosts pattern-triggered immunity

Author: Tian, Hainan, Wu, Zhongshou, Chen, Siyu, Ao, Kevin, Huang, Weijie, Yaghmaiean, Hoda, Sun, Tongjun, Xu, Fang, Zhang, Yanjun, Wang, Shucai, Li, Xin, Zhang, Yuelin

Issue&Volume: 2021-09-20

Abstract: Plant immune responses are mainly activated by two types of receptor. Plasma membrane-localized pattern recognition receptors (PRRs) perceive extracellular microbial features, and nucleotide-binding leucine-rich repeat receptors (NLRs) recognize intracellular effector proteins from pathogens1. NLRs possessing N-terminal Toll/interleukin-1 receptor (TIR) domains activate defence responses via the NADase activity of the TIR domain2,3. Here we report that activation of TIR signalling plays a key role in PRR-mediated pattern-triggered immunity (PTI). TIR signalling mutants exhibit attenuated PTI responses and decreased resistance against pathogens. Consistently, PTI is compromised in plants with reduced NLR levels. Treatment with PTI elicitor flg22 or nlp20 rapidly induces many genes encoding TIR domain-containing proteins, which is likely to be responsible for activating TIR signalling during PTI. Overall, our study reveals that TIR signalling activation is an important mechanism for boosting plant defence during PTI.

DOI: 10.1038/s41586-021-03987-1

Source: https://www.nature.com/articles/s41586-021-03987-1