State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Beijing 100101, China.
CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Beijing 100049, China.
FEMS Microbiol Rev. 2020 Nov 24;44(6):845-856. doi: 10.1093/femsre/fuaa035.
Receptor-like cytoplasmic kinases (RLCKs) play crucial roles in regulating plant development and immunity. Conserved pathogen-associated molecular patterns (PAMPs) derived from microbes are recognized by plant pattern recognition receptors to activate PAMP-triggered immunity (PTI). Microbial effectors, whose initial function is to promote virulence, are recognized by plant intracellular nucleotide-binding domain and leucine-rich repeat receptors (NLRs) to initiate effector-triggered immunity (ETI). Both PTI and ETI trigger early immune signaling events including the production of reactive oxygen species, induction of calcium influx and activation of mitogen-activated protein kinases. Research progress has revealed the important roles of RLCKs in the regulation of early PTI signaling. Accordingly, RLCKs are often targeted by microbial effectors that are evolved to evade PTI via diverse modulations. In some cases, modulation of RLCKs by microbial effectors triggers the activation of NLRs. This review covers the mechanisms by which RLCKs engage diverse substrates to regulate early PTI signaling and the regulatory roles of RLCKs in triggering NLR activation. Accumulating evidence suggests evolutionary links and close connections between PAMP- and effector-triggered early immune signaling that are mediated by RLCKs. As key immune regulators, RLCKs can be considered targets with broad prospects for the improvement of plant resistance via genetic engineering.
受体样细胞质激酶（RLCKs）在调节植物发育和免疫方面发挥着关键作用。源自微生物的保守病原体相关分子模式（PAMPs）被植物模式识别受体识别，从而激活病原相关分子模式触发的免疫（PTI）。微生物效应子的初始功能是促进毒力，被植物细胞内核苷酸结合域和富含亮氨酸重复受体（NLRs）识别，从而引发效应子触发的免疫（ETI）。PTI 和 ETI 都触发早期免疫信号事件，包括活性氧的产生、钙离子内流的诱导和丝裂原活化蛋白激酶的激活。研究进展揭示了 RLCKs 在调节早期 PTI 信号中的重要作用。因此，RLCKs 经常成为微生物效应子的靶标，这些效应子通过多种调节来逃避 PTI。在某些情况下，微生物效应子对 RLCKs 的调节会触发 NLR 的激活。本综述涵盖了 RLCKs 与各种底物相互作用以调节早期 PTI 信号的机制，以及 RLCKs 在触发 NLR 激活中的调节作用。越来越多的证据表明，RLCKs 介导的 PAMP 和效应子触发的早期免疫信号之间存在进化联系和紧密联系。作为关键的免疫调节剂，RLCKs 可以被认为是通过基因工程提高植物抗性的具有广阔前景的靶标。
