Zhong Kaili, Xu Gecheng, Shi Jingjing, Liu Peng, Tu Aizhu, Wu Mila, Liu Jiaqian, Chen Jianping, Yang Jian
State Key Laboratory for Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of MARA, Zhejiang Key Laboratory of Green Plant Protection, Institute of Plant Virology, Ningbo University, Ningbo, China.
PLoS Pathog. 2025 Apr 2;21(4):e1013037. doi: 10.1371/journal.ppat.1013037. eCollection 2025 Apr.
Papain-like cysteine proteases (PLCPs) play critical roles in regulating plant immunity against a range of pathogens and a series of cysteine protease inhibitors have been identified, however, relatively little research has been done on proteins that enhance the protease activity of PLCPs. Here, we identified a protein named NbPIRIN, the silencing of NbPIRIN promotes Chinese wheat mosaic virus (CWMV) infection, whereas the transgenic overexpression of NbPIRIN inhibits CWMV infection in Nicotiana benthamiana. Furthermore, we found that NbPIRIN interacts with papain-like cysteine protease (NbRD21) and increases its protease activity. We demonstrated that the silencing of NbRD21 significantly increased host susceptibility to CWMV infection, whereas the transgenic overexpression of NbRD21 increased host resistance. Interestingly, CWMV CRP was found to interact with both NbPIRIN and NbRD21, thus interfering with the interaction between NbPIRIN and NbRD21 and subsequently inhibiting the protease activity of NbRD21. Since wheat is the natural host of CWMV, we identified TaPIRIN and TaRD21 and found that they had functions similar to those of NbPIRIN and NbRD21 in the CWMV response. These results reveal a previously unreported offensive and defensive strategy between plants and viruses.
木瓜蛋白酶样半胱氨酸蛋白酶（PLCPs）在调节植物对多种病原体的免疫反应中起关键作用，并且已经鉴定出一系列半胱氨酸蛋白酶抑制剂，然而，对增强PLCPs蛋白酶活性的蛋白质的研究相对较少。在此，我们鉴定出一种名为NbPIRIN的蛋白质，沉默NbPIRIN会促进中国小麦花叶病毒（CWMV）感染，而NbPIRIN的转基因过表达则抑制本氏烟草中的CWMV感染。此外，我们发现NbPIRIN与木瓜蛋白酶样半胱氨酸蛋白酶（NbRD21）相互作用并增加其蛋白酶活性。我们证明，沉默NbRD21会显著增加宿主对CWMV感染的易感性，而NbRD21的转基因过表达则增强宿主抗性。有趣的是，发现CWMV CRP与NbPIRIN和NbRD21都相互作用，从而干扰NbPIRIN与NbRD21之间的相互作用，进而抑制NbRD21的蛋白酶活性。由于小麦是CWMV的天然宿主，我们鉴定出TaPIRIN和TaRD21，并发现它们在CWMV反应中具有与NbPIRIN和NbRD21相似的功能。这些结果揭示了植物与病毒之间以前未报道的攻防策略。
