Abstract：
The Australasian biogeographic realm is a major centre of diversity for orchids, with every subfamily of the Orchidaceae represented and high levels of endemism at the species rank. It is hypothesised that there is a commensurate diversity of viruses infecting this group of plants. In this study, we have utilised high-throughput sequencing to survey for viruses infecting greenhood orchids (Pterostylidinae) in New South Wales and the Australian Capital Territory. The main aim of this study was to characterise Pterostylis blotch virus (PtBV), a previously reported but uncharacterised virus that had been tentatively classified in the genus Orthotospovirus. This classification was confirmed by genome sequencing, and phylogenetic analyses suggested that PtBV is representative of a new species that is possibly indigenous to Australia as it does not belong to either the American or Eurasian clades of orthotospoviruses. Apart from PtBV, putative new viruses in the genera Alphaendornavirus, Amalgavirus, Polerovirus and Totivirus were discovered, and complete genome sequences were obtained for each virus. It is concluded that the polerovirus is likely an example of an introduced virus infecting a native plant species in its natural habitat, as this virus is probably vectored by an aphid, and Australia has a depauperate native aphid fauna that does not include any species that are host-adapted to orchids.
摘要：
澳大利亚的生物地理领域是兰花多样性的主要中心，兰科的每个亚科都有代表，并且在物种等级上具有很高的特有性。假设感染这组植物的病毒具有相当的多样性。在这项研究中,我们已经利用高通量测序来调查感染新南威尔士州和澳大利亚首都地区的绿色兰花（Pterostylidinae）的病毒。这项研究的主要目的是表征Pterostylis斑点病毒（PtBV），一种先前报道但未鉴定的病毒，已被初步归类为直角孢子病毒属。基因组测序证实了这种分类，系统发育分析表明，PtBV代表了可能是澳大利亚本土的新物种，因为它既不属于美国也不属于欧亚大陆的正孢子病毒分支。除了PtBV,Alphaendernavirus属中假定的新病毒，汞合金病毒，发现了Polerovirus和Totivirus，并获得每种病毒的完整基因组序列。结论是，polerovirus可能是引入的病毒感染其自然栖息地中的本地植物物种的一个例子，因为这种病毒可能是由蚜虫传播的，澳大利亚有一个贫瘠的本地蚜虫动物区系，不包括任何适应兰花的寄主物种。
