Purpose of Review

The collective virome of forest trees can be considered to include not only plant viruses, but also viral communities harbored by all tree-associated organisms. In this review, we will concentrate on reviewing recent developments in the two fields of forest tree virology that have received the most research input during the last 5 years: (1) current knowledge of virus diseases affecting forest trees and their causal agents and (2) fungal viruses (mycoviruses) and properties that are required for utilizing them for biocontrol purposes.

Recent Findings

The discovery of plant and mycoviruses has been revolutionized during the last few years due to high-throughput sequencing (HTS). This has altered our view of virus diversity and prevalence, but also their host ranges, transmission routes, and host effects. Utilization of HTS has greatly expanded our knowledge of plant virus diversity and disease etiology in forest trees and revealed the commonness of cross-kingdom transmission events between fungi, oomycetes, plants, and arthropods. Research on mycoviruses has also identified several new mycoviruses that restrict the growth or virulence of forest pathogenic fungi.

Summary

Gaining knowledge of the collective virome of forest ecosystems is essential not only for understanding virus evolution and diversity but also for improving our understanding on virus impacts, and our ability for biocontrol-based and environmentally friendly management of viral and fungal diseases that affect economically important plants and beneficial insects, and for preventing possible disease outbreaks in the future. Virus infections play a central role in plant health, but viral symptoms on forest trees remain often unrecognized and may be confused with other biotic or abiotic damages. However, recent studies have revealed previously unknown viruses as causes of forest tree symptoms and suggest that viruses are responsible for far greater economic losses than recognized earlier. However, many knowledge gaps still need to be filled, particularly on the diversity of viruses that infect different species of forest trees, their irregular distribution within the plant, their mode of transmission, epidemiology and choice of hosts also regarding crop plants, their effect on the metabolism of their host tree, and their interaction with other microorganisms. Mycovirus research has already deciphered detailed information on many critical properties that affect utilizing them for biocontrol purposes. Still, more knowledge is needed concerning mycoviral transmission mode and stability in field conditions, the level of host tolerance against mycoviral infection, and the occurrence of interspecies mycovirus transmission in nature, and safety issues related to these topics.

中文翻译：

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林木病毒组作为树木病害和生物防治剂的来源

审查目的

森林树木的集体病毒组可以被认为不仅包括植物病毒，还包括所有与树木相关的生物体所携带的病毒群落。在这篇综述中，我们将集中回顾过去 5 年来获得最多研究投入的林木病毒学两个领域的最新进展：(1) 目前对影响林木及其致病因子的病毒病的了解和 (2) ）真菌病毒（真菌病毒）以及利用它们进行生物防治所需的特性。

最近的发现

由于高通量测序 (HTS)，植物和真菌病毒的发现在过去几年中发生了革命性的变化。这改变了我们对病毒多样性和流行性的看法，也改变了它们的宿主范围、传播途径和宿主效应。 HTS 的利用极大地扩展了我们对森林树木植物病毒多样性和疾病病因学的了解，并揭示了真菌、卵菌、植物和节肢动物之间跨界传播事件的共性。对真菌病毒的研究还发现了几种限制森林病原真菌生长或毒力的新真菌病毒。

概括

获得森林生态系统集体病毒组的知识不仅对于了解病毒进化和多样性至关重要，而且对于提高我们对病毒影响的理解以及对影响经济重要植物的病毒和真菌病害进行基于生物防治和环境友好的管理的能力至关重要和有益昆虫，并预防未来可能爆发的疾病。病毒感染在植物健康中发挥着核心作用，但林木上的病毒症状常常未被识别，并且可能与其他生物或非生物损害相混淆。然而，最近的研究揭示了以前未知的病毒是导致林树症状的原因，并表明病毒造成的经济损失比之前认识到的要大得多。然而，仍然有许多知识空白需要填补，特别是感染不同种类林木的病毒的多样性、它们在植物内的不规则分布、它们的传播方式、流行病学和宿主的选择，以及作物植物的宿主的选择、它们对植物的影响。宿主树的新陈代谢，以及它们与其他微生物的相互作用。真菌病毒研究已经破译了许多影响其用于生物防治目的的关键特性的详细信息。尽管如此，仍需要更多关于真菌病毒传播模式和野外条件下的稳定性、宿主对真菌病毒感染的耐受水平、自然界中种间真菌病毒传播的发生以及与这些主题相关的安全问题的更多知识。