The use of transmissible hypovirulence for the biological control of Ophiostoma, the causal agent of Dutch elm disease

利用传染性低毒力对荷兰榆树病的病原体蛇口线虫进行生物防治

• 批准号: 138387-2013
• 负责人: Hintz, William
• 金额: $ 1.82万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=545525
• 关键词: use; transmissible; hypovirulence; biological; control

Natural and urban populations of the American elm have been devastated by pathogenic fungi of the genus Ophiostoma, the causal agent of Dutch elm disease (DED). Control of this pathogen has focused on fungicides to stem the growth of the fungus or pesticides to control the spread of the insect vector however neither option has been very effective. An attractive alternative to the use of chemical pesticides or fungicides is the development of a biological control for O. novo-ulmi. This requires, at minimum, an agent that is antagonistic to the fungus, is transmissible to extant populations of the fungus in the field, and is very specific to minimize off-target effects. Hypovirulence is the decreased virulence of a pathogen towards its host and can result from many causes including mitochondrial DNA mutations, nuclear genome mutations or the presence of mycoviruses. We intend to extend the application of transmissible hypovirulence for the management of fungal pathogens by the development of a transmissible disease control using engineered dsRNA vectors for the biological control of DED. Induction of hypovirulence via mycoviruses could readily be applied to O. novo-ulmi as the target population at the western Canadian disease front is essentially composed of two very large clones and vegetative compatibility barriers are rare. We have determined the genome sequence of a new dsRNA mitovirus OnuMV1c isolated from an infected O. novo-ulmi at disease front and demonstrated its transmission between strains. Partitiviruses, which reside in the cytoplasm, have been described in closely related species and are expected to be transmissible to O. novo-ulmi. Through our work on the genomics of O. novo-ulmi we have identified several gene loci thought to be integral to pathogenicity and fungal fitness. We intend to embark on the re-engineering of viral dsRNAs by the insertion of silencing RNA (siRNA) specific to identified O. novo-ulmi gene loci to selectively down-regulate genes critical to fungal survival. The development of RNAi engineered hypoviruses could provide a new approach for biological control that would be applicable to many fungal pathogens.

美国榆树的自然和城市种群已被荷兰榆树病的因果因素（DED）的ophiostoma属的致病真菌破坏。 对这种病原体的控制集中在杀菌剂上，以阻止真菌或农药的生长以控制昆虫载体的扩散，但是两种选择都不是很有效的。使用化学农药或杀真菌剂的一种有吸引力的替代方法是开发O. Novo-Ulmi的生物控制。 这至少需要一种与真菌拮抗的药物，它是对现有真菌的现有种群传播的，并且非常特定于最大程度地减少脱靶效应。缺乏性不足是病原体对其宿主的毒力降低，可能是由于线粒体DNA突变，核基因组突变或分支病毒的存在所致。我们打算通过使用工程的DSRNA媒介来开发可传染性的疾病控制来扩展可透射性不足的不适用于对真菌病原体的管理。 由于西部加拿大疾病前部的目标种群基本上由两个非常大的克隆组成，并且很少有通过菌病毒诱导通过菌病毒诱导不足。我们已经确定了从感染的novo-ulmi在疾病前部被感染的O. novo-ulmi分离出的新的dsRNA mitovirus onumv1c的基因组序列，并证明了其在菌株之间的传播。 驻留在细胞质中的partivires已在密切相关的物种中描述，预计将被O. Novo-Ulmi传播。通过我们在O. Novo-Ulmi的基因组学上的工作，我们确定了几个基因基因座被认为是致病性和真菌适应性不可或缺的。 我们打算通过插入对已鉴定的O. Novo-Ulmi基因位点的插入沉默RNA（siRNA）来重新设计病毒DSRNA，以选择性地下调对真菌生存至关重要的基因。 RNAi工程性下种病毒的发展可以为生物控制提供一种新方法，该方法适用于许多真菌病原体。