A novel flavivirus in the soybean cyst nematode
A novel flavivirus in the soybean cyst nematode
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DOI：
10.1099/vir.0.060889-0
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发表时间：
2014-06-01
影响因子：
3.8
通讯作者：
Bhalerao, Kaustubh
中科院分区：
文献类型：
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作者：
Bekal, Sadia;Domier, Leslie L.;Bhalerao, Kaustubh
大豆囊线虫（Heterodera glycine，简称SCN）是一种地下根系病原菌，是美国大豆最具破坏性的病害。从大豆包囊线虫卵和二期幼虫的RNA测序数据中鉴定出一种新的线虫病毒基因组——大豆包囊线虫病毒5 （SbCNV-5）。SbCNV-5的RNA依赖RNA聚合酶和RNA解旋酶结构域与黄病毒科鼠疫病毒具有同源性，提示SbCNV-5是一种正极性的ssRNA病毒。SbCNV-5 RNA存在于线虫的所有发育阶段，表明其传播方式是经卵巢传播的，但也可能通过雄性进行性传播。SbCNV-5在SCN实验室培养物和从田间分离的线虫种群中很常见。雌性SCN切片的透射电镜显示病毒颗粒从内质网和核内体出芽。病毒基因组的大小为1919nt，这使得它比其他已知的鼠疫病毒大得多。此外，SbCNV-5基因组中甲基转移酶的存在对于鼠疫病毒来说是非典型的。当将cDNA序列映射到SbCNV-5的基因组时，与3' NTR对齐的数量不成比例，表明SbCNV-5产生亚基因组RNA， RNA印迹分析证实了这一点。由于鼠疫病毒中不存在亚基因组rna和甲基转移酶，我们认为SbCNV-5是一种感染SCNs的新型黄病毒。
Heterodera glycines, the soybean cyst nematode (SCN), is a subterranean root pathogen that causes the most damaging disease of soybean in the USA. A novel nematode virus genome, soybean cyst nematode virus 5 (SbCNV-5), was identified in RNA sequencing data from SCN eggs and second-stage juveniles. The SbCNV-5 RNA-dependent RNA polymerase and RNA helicase domains had homology to pestiviruses in the family Flaviviridae, suggesting that SbCNV-5 is a positive-polarity ssRNA virus. SbCNV-5 RNA was present in all nematode developmental stages, indicating a transovarial mode of transmission, but is also potentially sexually transmitted via the male. SbCNV-5 was common in SCN laboratory cultures and in nematode populations isolated from the field. Transmission electron microscopy of sections from a female SCN showed virus particles budding from the endoplasmic reticulum and in endosomes. The size of the viral genome was 19 191 nt, which makes it much larger than other known pestiviruses. Additionally, the presence of a methyltransferase in the SbCNV-5 genome is atypical for a pestivirus. When cDNA sequences were mapped to the genome of SbCNV-5, a disproportionate number aligned to the 3' NTR, suggesting that SbCNV-5 produces a subgenomic RNA, which was confirmed by RNA blot analysis. As subgenomic RNAs and methyltransferases do not occur in pestiviruses, we conclude that SbCNV-5 is a new flavivirus infecting SCNs.