Jiang Junyun, Ni Shuang, Wang Shuo, Xie Li, Li Zhenghe
State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China.
Mol Plant Pathol. 2025 Sep;26(9):e70152. doi: 10.1111/mpp.70152.
Superinfection exclusion (SIE) is a finely tuned virus-virus interaction mechanism closely linked to the viral infection cycle. However, the mechanistic basis of SIE remains incompletely understood in plant viruses, particularly among negative-sense, single-stranded RNA viruses. In this study, we first describe the development of an efficient reverse genetics system for the plant nucleorhabdovirus Physostegia chlorotic mottle virus (PhCMoV) by codon optimisation of the large polymerase coding sequence. Using fluorescently tagged variants of PhCMoV, as well as three additional closely or distantly related plant rhabdoviruses, we found that each rhabdovirus displayed homotypic SIE. Moreover, two closely related alphanucleorhabdoviruses, PhCMoV and eggplant mottled dwarf virus, also exhibited mutual exclusion. Loss- and gain-of-function reverse genetics analyses identified the rhabdovirus matrix (M) protein as the central SIE effector: M-deficient mutant viruses lost exclusion capacity, whereas ectopically expressed heterologous M proteins conferred SIE against otherwise compatible, distantly related rhabdoviruses. Additional functional assays demonstrated that the ability of rhabdovirus M proteins to suppress cognate and noncognate viral RNA synthesis correlated with the intra- and interspecies SIE capacity. The widespread occurrence of SIE across distinct plant rhabdoviruses underscores its importance for understanding the viral replication cycle and highlights its practical relevance for the development of novel virus control strategies.
超感染排除（SIE）是一种与病毒感染周期紧密相连的精细调节的病毒-病毒相互作用机制。然而，在植物病毒中，尤其是在负链单链RNA病毒中，SIE的机制基础仍未完全了解。在本研究中，我们首先通过对大聚合酶编码序列进行密码子优化，描述了一种针对植物核多角体病毒紫苏褪绿斑驳病毒（PhCMoV）的高效反向遗传学系统的开发。使用荧光标记的PhCMoV变体以及另外三种密切或远缘相关的植物弹状病毒，我们发现每种弹状病毒都表现出同型SIE。此外，两种密切相关的α核多角体病毒，PhCMoV和茄子斑驳矮化病毒，也表现出相互排斥。功能丧失和功能获得反向遗传学分析确定弹状病毒基质（M）蛋白是核心SIE效应因子：缺乏M的突变病毒失去了排除能力，而异位表达的异源M蛋白赋予了对原本兼容的远缘相关弹状病毒的SIE。额外的功能测定表明，弹状病毒M蛋白抑制同源和非同源病毒RNA合成的能力与种内和种间SIE能力相关。SIE在不同植物弹状病毒中的广泛存在强调了其对于理解病毒复制周期的重要性，并突出了其在新型病毒控制策略开发中的实际相关性。
