State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Viruses. 2022 Feb 23;14(3):456. doi: 10.3390/v14030456.
Endornaviruses are capsidless linear (+) ssRNA viruses in the family . In this study, Scelrotinia sclerotiorum endornavirus 11 (SsEV11), a novel endornavirus infecting hypovirulent strain XY79, was identified and cloned using virome sequencing analysis and rapid amplification of cDNA ends (RACE) techniques. The full-length genome of SsEV11 is 11906 nt in length with a large ORF, which encodes a large polyprotein of 3928 amino acid residues, containing a viral methyltransferase domain, a cysteine-rich region, a putative DEADc, a viral helicase domain, and an RNA-dependent RNA polymerase (RdRp) 2 domain. The 5' and 3' untranslated regions (UTR) are 31 nt and 90 nt, respectively. According to the BLAST result of the nucleotide sequence, SsEV11 shows the highest identity (45%) with Sclerotinia minor endornavirus 1 (SmEV1). Phylogenetic analysis based on amino acid sequence of RdRp demonstrated that SsEV11 clusters to endornavirus and has a close relationship with . Phylogenetic analysis based on the sequence of endornaviral RdRp domain indicated that there were three large clusters in the phylogenetic tree. Combining the results of alignment analysis, Cluster I at least has five subclusters including typical members of and many unclassified endornaviruses that isolated from fungi, oomycetes, algae, and insects; Cluster II also has five subclusters including typical members of , SsEV11, and other unclassified viruses that infected fungi; Cluster III includes many endorna-like viruses that infect nematodes, mites, and insects. Viruses in Cluster I and Cluster II are close to each other and relatively distant to those in Cluster III. Our study characterized a novel betaendornavirus, SsEV11, infected fungal pathogen , and suggested that notable phylogenetic diverse exists in endornaviruses. In addition, at least, one novel genus, Gammaendornavirus, should be established to accommodate those endorna-like viruses in Cluster III.
内生病毒是一类无衣壳的线状(+)ssRNA 病毒，属于. 在本研究中，通过病毒组测序分析和快速扩增 cDNA 末端（RACE）技术，鉴定并克隆了感染弱毒菌株 XY79 的新型内生病毒——核盘菌内生病毒 11（SsEV11）。SsEV11 的全长基因组为 11906 个核苷酸，包含一个大的开放阅读框，编码一个由 3928 个氨基酸残基组成的大型多蛋白，其中包含一个病毒甲基转移酶结构域、一个富含半胱氨酸的区域、一个假定的 DEADc 结构域、一个病毒解旋酶结构域和一个 RNA 依赖的 RNA 聚合酶（RdRp）2 结构域。5'和 3'非翻译区（UTR）分别为 31 个核苷酸和 90 个核苷酸。根据核苷酸序列的 BLAST 结果，SsEV11 与小核盘菌内生病毒 1（SmEV1）的同源性最高（45%）。基于 RdRp 氨基酸序列的系统发育分析表明，SsEV11 聚类到内生病毒中，与. 基于内生病毒 RdRp 结构域序列的系统发育分析表明，系统发育树中有三个大的聚类。结合比对分析的结果，聚类 I 至少有五个亚群，包括典型成员和许多未分类的内生病毒，这些病毒分离自真菌、卵菌、藻类和昆虫；聚类 II 也有五个亚群，包括典型成员、SsEV11 和其他未分类的感染真菌的病毒；聚类 III 包括许多感染线虫、螨虫和昆虫的内生样病毒。聚类 I 和聚类 II 中的病毒彼此接近，而与聚类 III 中的病毒相对较远。本研究描述了一种新型的β内生病毒 SsEV11，它感染真菌病原体核盘菌，并表明内生病毒存在显著的系统发育多样性。此外，至少应该建立一个新的属，Gammaendornavirus，以容纳聚类 III 中的那些内生样病毒。
