In many eukaryotes, small RNAs (sRNAs) can mediate gene expression regulation through a mechanism known as RNA silencing. In fungi, RNA silencing plays a crucial role in numerous biological processes, including parasitic and mutualistic fungus-plant interactions. This review summarizes recent findings on the role of RNA silencing in parasitic fungus-fungus and fungus-insect interactions in relation to their use for the biological control (biocontrol) of fungal plant diseases and insect damage. Genes belonging to the RNA silencing machinery are identified in the genomes of almost all known fungal and oomycete biocontrol organisms. However, recent functional genetic studies in Ascomycota species of the Hypocreales order, such as and , show how RNA silencing can have family-specific effects, as conidiation is affected differently in the two organisms when the same elements of the RNA silencing machinery are deleted. The size of sRNAs regulated by RNA silencing can also vary between organisms. Cross-species RNA silencing represents a new field in the study of antagonistic interactions. For example, a microRNA (miRNA) of another hypocrealean fungus, was proven to target genes involved in the immune response of mosquitoes, and there are indications that miRNAs from the mycoparasitic may target factors of virulence in its plant-pathogenic host fungi. Accumulating evidence from many species shows that the number of endogenous genes affected by the disruption of the RNA silencing mechanism is always much higher than the number of predicted direct target genes. As several putative targets of fungal sRNAs are transcription factors, it is possible that specific sRNAs have a role as master regulators of gene expression, affecting the transcription of a high number of genes through cascading regulating effects. The challenges faced when studying cross-species RNA silencing, including sRNA trafficking during mycoparasitism, are also discussed. This includes the difficulties in separating the extracellular vesicles of mycoparasitic fungi from those of their hosts, the high amount of sequencing reads lost in bioinformatics filtering steps, imprecise target prediction and the lack of a streamlined accepted way of reporting results.

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小RNA：用于生物防治的真菌-真菌相互作用的新范例


在许多真核生物中，小 RNA (sRNA) 可以通过一种称为 RNA 沉默的机制介导基因表达调控。在真菌中，RNA 沉默在许多生物过程中发挥着至关重要的作用，包括寄生和共生的真菌-植物相互作用。这篇综述总结了RNA沉默在寄生真菌-真菌和真菌-昆虫相互作用中的作用的最新发现，以及它们在真菌植物病害和昆虫损害的生物防治（生物防治）中的应用。属于 RNA 沉默机制的基因在几乎所有已知的真菌和卵菌生物防治生物体的基因组中都得到了鉴定。然而，最近对肉座菌目的子囊菌门物种（例如 和 ）的功能遗传学研究表明，RNA 沉默如何产生科特异性效应，因为当删除 RNA 沉默机制的相同元件时，两种生物体中的分生孢子受到不同的影响。受 RNA 沉默调节的 sRNA 的大小在生物体之间也可能有所不同。跨物种RNA沉默代表了拮抗相互作用研究的一个新领域。例如，另一种次生真菌的 microRNA (miRNA) 被证明能够靶向参与蚊子免疫反应的基因，并且有迹象表明，来自真菌寄生菌的 miRNA 可能靶向其植物病原性宿主真菌中的毒力因子。来自许多物种的不断积累的证据表明，受RNA沉默机制破坏影响的内源基因的数量总是远高于预测的直接靶基因的数量。 由于真菌 sRNA 的几个假定靶标是转录因子，因此特定 sRNA 可能具有基因表达主调节因子的作用，通过级联调节效应影响大量基因的转录。还讨论了研究跨物种 RNA 沉默（包括真菌寄生过程中 sRNA 运输）时面临的挑战。这包括将菌寄生真菌的细胞外囊泡与其宿主的细胞外囊泡分离的困难、生物信息学过滤步骤中丢失的大量测序读数、不精确的目标预测以及缺乏简化的、可接受的结果报告方式。