Zhang Xin, Peng Huan, Zhu Sirui, Xing Junjie, Li Xin, Zhu Zhaozhong, Zheng Jingyuan, Wang Long, Wang Bingqian, Chen Jia, Ming Zhenhua, Yao Ke, Jian Jinzhuo, Luan Sheng, Coleman-Derr Devin, Liao Hongdong, Peng Yousong, Peng Deliang, Yu Feng
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, P.R. China.
State Key Laboratory of Plant Disease and Insect Pest, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, P.R. China.
Mol Plant. 2020 Oct 5;13(10):1434-1454. doi: 10.1016/j.molp.2020.08.014. Epub 2020 Sep 4.
The molecular mechanism by which plants defend against plant root-knot nematodes (RKNs) is largely unknown. The plant receptor kinase FERONIA and its peptide ligands, rapid alkalinization factors (RALFs), regulate plant immune responses and cell expansion, which are two important factors for successful RKN parasitism. In this study, we found that mutation of FERONIA in Arabidopsis thaliana resulted in plants showing low susceptibility to the RKN Meloidogyne incognita. To identify the underlying mechanisms associated with this phenomenon, we identified 18 novel RALF-likes from multiple species of RKNs and showed that two RALF-likes (i.e., MiRALF1 and MiRALF3) from M. incognita were expressed in the esophageal gland with high expression during the parasitic stages of nematode development. These nematode RALF-likes also possess the typical activities of plant RALFs and can directly bind to the extracellular domain of FERONIA to modulate specific steps of nematode parasitism-related immune responses and cell expansion. Genetically, both MiRALF1/3 and FERONIA are required for RKN parasitism in Arabidopsis and rice. Collectively, our study suggests that nematode-encoded RALFs facilitate parasitism via plant-encoded FERONIA and provides a novel paradigm for studying host-pathogen interactions.
植物抵御植物根结线虫（RKNs）的分子机制在很大程度上尚不清楚。植物受体激酶FERONIA及其肽配体快速碱化因子（RALFs）调节植物免疫反应和细胞扩张，这是根结线虫成功寄生的两个重要因素。在本研究中，我们发现拟南芥中FERONIA的突变导致植物对南方根结线虫表现出低易感性。为了确定与这一现象相关的潜在机制，我们从多种根结线虫中鉴定出18种新的类RALF，并表明南方根结线虫的两种类RALF（即MiRALF1和MiRALF3）在食管腺中表达，在 nematode发育的寄生阶段表达量很高。这些线虫类RALF也具有植物RALF的典型活性，并且可以直接结合FERONIA的胞外结构域，以调节线虫寄生相关免疫反应和细胞扩张的特定步骤。在遗传学上，MiRALF1/3和FERONIA都是拟南芥和水稻中根结线虫寄生所必需的。总的来说，我们的研究表明，线虫编码的RALF通过植物编码的FERONIA促进寄生作用，并为研究宿主-病原体相互作用提供了一种新的模式。
