State Key Laboratory for Agro-Biotechnology, and Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant Pathology, China Agricultural University, Beijing, 100193, China.
Department of Plant Pathology, Shandong Agricultural University, Tai'an, 271018, China.
Arch Virol. 2021 Jul;166(7):1921-1930. doi: 10.1007/s00705-021-05077-z. Epub 2021 Apr 27.
Positive-stranded RNA viruses usually remodel the host endomembrane system to form virus-induced intracellular vesicles for replication during infections. The genus Potyvirus of the family Potyviridae represents the largest number of positive single-stranded RNA viruses, and its members cause great damage to crop production worldwide. Although potyviruses have a wide host range, each potyvirus infects a relatively limited number of host species. Phylogenesis and host range analysis can divide potyviruses into monocot-infecting and dicot-infecting groups, suggesting that they differ in their infection mechanisms, probably during replication. Comprehensive studies on the model dicot-infecting turnip mosaic virus have shown that the 6K2-induced replication vesicles are derived from the endoplasmic reticulum (ER) and subsequently target chloroplasts for viral genome replication. However, the replication site of monocot-infecting potyviruses is unknown. In this study, we show that the precursor 6K2-VPg-Pro polyproteins of dicot-infecting potyviruses and monocot-infecting potyviruses cluster phylogenetically in two separate groups. With a typical gramineae-infecting potyvirus-sugarcane mosaic virus (SCMV)-we found that replicative double-stranded RNA (dsRNA) forms aggregates in the cytoplasm but does not associate with chloroplasts. SCMV 6K2-VPg-Pro-induced vesicles colocalize with replicative dsRNA. Moreover, SCMV 6K2-VPg-Pro-induced structures target multiple intracellular organelles, including the ER, Golgi apparatus, mitochondria, and peroxisomes, and have no evident association with chloroplasts.
正链 RNA 病毒通常会重塑宿主内膜系统，在感染过程中形成病毒诱导的细胞内囊泡以进行复制。壶腹病毒科壶腹病毒属是正单链 RNA 病毒中数量最多的，其成员对全球作物生产造成了巨大破坏。尽管壶腹病毒具有广泛的宿主范围，但每种壶腹病毒感染的宿主物种相对有限。系统发育和宿主范围分析可以将壶腹病毒分为单子叶植物侵染组和双子叶植物侵染组，这表明它们在感染机制上存在差异，可能在复制过程中存在差异。对模式双子叶植物侵染的芜菁花叶病毒的综合研究表明，6K2 诱导的复制囊泡来源于内质网（ER），随后靶向叶绿体进行病毒基因组复制。然而，单子叶植物侵染的壶腹病毒的复制位点尚不清楚。在本研究中，我们表明，双子叶植物侵染的壶腹病毒和单子叶植物侵染的壶腹病毒的前体 6K2-VPg-Pro 多蛋白在系统发育上聚类为两个独立的组。以典型的禾本科侵染的壶腹病毒-甘蔗花叶病毒（SCMV）为例，我们发现复制性双链 RNA（dsRNA）在细胞质中形成聚集体，但不与叶绿体结合。SCMV 6K2-VPg-Pro 诱导的囊泡与复制性 dsRNA 共定位。此外，SCMV 6K2-VPg-Pro 诱导的结构靶向多个细胞内细胞器，包括内质网、高尔基体、线粒体和过氧化物酶体，与叶绿体没有明显的关联。
