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Studies on replication, pathogenicity and transmission of plant RNA viruses in the genus Furovirus

糠疹病毒属植物RNA病毒的复制、致病性和传播研究

基本信息

批准号：
13460020
负责人：
SHIRAKO Yukio
金额：
$ 10.11万
依托单位：
THE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13460020/
关键词：
genus Furovirus Soil-borne wheat mosaic virus RNA reassorment infectious cDNA clone barley mesophyl protoplast viral RNA replication pathogenicity transmissibility 欠失変異

项目摘要

Soil-borne wheat mosaic virus (SBWMV) is the type species in the genus Furovirus with bipartite plus-sense RNA genome encapsidated in rod-shaped virions. SBWMV infects wheat and barley plants, causing mosaic and stunt diseaese. SBWMV is transmitted by and retained in soil-inhabiting fungus and therefore it is quite difficult to control this virus disease from the infested field. In this study, we investigated replication, pathogenicity and transmission of SBWMV for the purpose of controlling the disease.1. Three full-length infectious cDNA clones for Japanese, American and English isolates of SBWMV were constructed. Also, an infectivity assay, a barley mesophyl protoplasts system was developed for SBWMV. Reassortment experiments among the three isolates using barley protoplasts showed that all RNA1 and RNA2 combinations supported viral RNA replication, indicating a close relationship among the three geographical isolates.2. Infection of SBWMV to wheat plants requires temperatures lower than 20 ℃. Barley protoplasts inoculated with infectious in vitro transcripts were incubated at temperatures between 15 ℃ and 25 ℃, and it was proved that the optimal temperature for RNA replication is 17 ℃.3. Wild-type RNA2 of SBWMV undergoes frequent deletion mutation when the virus was passaged at 17 ℃ and deletion mutants cause more severe symptoms on wheat plants that the wild-type virus. Deletion mutation was analyzed using full-length infectious RNA2 transcripts in inoculum and found to occur in-frame to the upstream capsid protein gene. Symptom severities correlated with the length of deletion.As described above, the fundamental information, materials and methods were obtained for further detailed analysis on replication, pathogenicity and transmission of furoviruses.

土传小麦花叶病毒（SBWMV）是糠病毒属的模式种，其二分正链RNA基因组包裹在杆状病毒体中。 SBWMV 感染小麦和大麦植物，引起花叶病和矮化病。 SBWMV 通过土壤真菌传播并保留在其中，因此从受感染的田地控制这种病毒病是相当困难的。本研究对SBWMV的复制、致病性和传播途径进行了研究，以达到控制该病的目的。 1．构建了日本、美国和英国 SBWMV 分离株的三个全长感染性 cDNA 克隆。此外，还为 SBWMV 开发了感染性测定、大麦叶肉原生质体系统。使用大麦原生质体对三个分离株进行重配实验表明，所有RNA1和RNA2组合都支持病毒RNA复制，表明三个地理分离株之间的密切关系。2． SBWMV感染小麦植株需要温度低于20℃。将感染性体外转录本接种的大麦原生质体在15℃～25℃的温度下培养，证明RNA复制的最适温度为17℃。3． SBWMV野生型RNA2在17℃传代时发生频繁的缺失突变，缺失突变体对小麦植株造成比野生型病毒更严重的症状。使用接种物中的全长感染性 RNA2 转录物分析缺失突变，发现缺失突变发生在上游衣壳蛋白基因的框内。症状严重程度与缺失长度相关。如上所述，为进一步详细分析糠疹病毒的复制、致病性和传播性提供了基础信息、材料和方法。