Introns, nested introns and intron encoded proteins in the mitochondrial genomes of fungi.

真菌线粒体基因组中的内含子、嵌套内含子和内含子编码蛋白质。

• 批准号: RGPIN-2020-05332
• 负责人: Hausner, Georg
• 金额: $ 3.06万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=717596
• 关键词: Introns; nested; introns; intron; encoded

Many species of Ophiostoma, Grosmannia and Ceratocystis are vectored by insects such as bark beetles, and these fungi are commonly known as blue-stain fungi as they discolour lumber, thus reducing the economic value of the wood. These fungi are also referred to as the ophiostomatoid fungi; and, this group includes tree pathogens such as the causative agents of Dutch Elm Disease or Oak wilt. This research program focuses in part on the taxonomy and evolution of blue-stain fungi. Characterizing mitochondrial genomes of blue-stain fungi is part of the long-term objectives of this proposal. The more immediate goals are to understand the origin and persistence of mobile genetic elements within fungal mitochondrial genomes (mtDNA) and to examine the implications these elements have on mtDNA stability and potentially on the virulence of these tree pathogens. The proposed work over the next five years will focus on characterizing the mitochondrial genomes of Ophiostoma ulmi and related species such as O. novo-ulmi, O. himal-ulmi and species related to the O. ulmi complex. The relative low cost and speed of next generation sequencing allows for sequencing of mtDNAs from many ophiostomatoid fungi, and comparative analysis of the resulting data will provide a resource for possible identifying inter-specific markers for identification of economically important fungi. Also comparing the mtDNA of closely related species should reveal the impact of mobile elements such as mobile introns (group I and group II introns) on mtDNA genome evolution. Sometimes these mobile introns can insert into other introns, forming nested intron arrangements. To understand how these complex introns are actually processed within the mitochondria the RNA will be sequenced to recover splicing intermediates. These fungi are strict aerobic organisms, therefore functional mitochondria are essential. Mobile introns have been associated with mitochondrial defects and these elements contribute towards the size and the architecture of fungal mitochondrial genomes. This work may elucidate the splicing pathways for nested introns and possibly reveal elements that could serve as regulatory elements. It has recently been suggested the group I intron splicing could be a target for therapeutic applications with regards to human pathogenic fungi or potential fungicides for plant pathogens. Gaining knowledge about mtDNA intron splicing and the impact of mobile introns on fungal mtDNAs could be valuable information when developing strategies to identify and control plant pathogens, such as members of the blue-stain fungi. In addition these mobile elements frequently encode site-specific DNA cutting enzymes, so called homing endonucleases. These enzymes have application in genomics and biotechnology as genome editing reagents.

许多蛇口属、格罗斯曼属和角囊属都是由树皮甲虫等昆虫传播的，这些真菌通常被称为蓝染真菌，因为它们会使木材变色，从而降低木材的经济价值。这些真菌也称为蛇口真菌；并且，该组包括树木病原体，例如荷兰榆树病或橡树枯萎病的病原体。该研究计划部分侧重于蓝染真菌的分类和进化。表征蓝染真菌的线粒体基因组是该提案长期目标的一部分。更直接的目标是了解真菌线粒体基因组 (mtDNA) 内移动遗传元件的起源和持久性，并检查这些元件对 mtDNA 稳定性以及对这些树病原体的毒力的潜在影响。未来五年的拟议工作将集中于表征 Ophiostoma ulmi 和相关物种（例如 O. novo-ulmi、O. Himal-ulmi 和与 O. ulmi 复合体相关的物种）的线粒体基因组。下一代测序的相对较低的成本和速度允许对许多蛇口类真菌的线粒体DNA进行测序，并且对所得数据的比较分析将为可能识别种间标记以鉴定经济上重要的真菌提供资源。此外，比较密切相关物种的 mtDNA 应该揭示移动元件（例如移动内含子（I 组和 II 组内含子））对 mtDNA 基因组进化的影响。有时，这些移动内含子可以插入其他内含子，形成嵌套内含子排列。为了了解这些复杂的内含子实际上是如何在线粒体内加工的，将对 RNA 进行测序以恢复剪接中间体。这些真菌是严格的需氧生物，因此功能性线粒体至关重要。移动内含子与线粒体缺陷有关，这些元件有助于真菌线粒体基因组的大小和结构。这项工作可能阐明嵌套内含子的剪接途径，并可能揭示可作为调控元件的元件。最近有人提出，I 组内含子剪接可能成为人类病原真菌或植物病原体潜在杀真菌剂的治疗应用的靶点。在制定识别和控制植物病原体（例如蓝染真菌成员）的策略时，了解有关 mtDNA 内含子剪接以及移动内含子对真菌 mtDNA 的影响可能是有价值的信息。此外，这些移动元件经常编码位点特异性 DNA 切割酶，即所谓的归巢核酸内切酶。这些酶作为基因组编辑试剂在基因组学和生物技术中得到应用。