Mycoviruses infect fungi, and while most persist asymptomatically, there are examples of mycoviruses having both beneficial and detrimental effects on their host. Virus-infected Saccharomyces and Ustilago strains exhibit a killer phenotype conferring a growth advantage over uninfected strains and other competing yeast species, whereas hypovirus-infected Cryphonectria parasitica displays defects in growth, sporulation, and virulence. In this study, we identify a double-stranded RNA (dsRNA) mycovirus in five Malassezia species. Sequence analysis reveals it to be a totivirus with two dsRNA segments: a larger 4.5-kb segment with genes encoding components for viral replication and maintenance, and a smaller 1.4-kb segment encoding a novel protein. Furthermore, transcriptome sequencing (RNA-seq) of virus-infected versus virus-cured Malassezia sympodialis revealed an upregulation of dozens of ribosomal components in the cell, suggesting the virus modifies the transcriptional and translational landscapes of the cell. Given that Malassezia is the most abundant fungus on human skin, we assessed the impact of the mycovirus in a murine epicutaneous infection model. Although infection with virus-infected strains was not associated with an increased inflammatory response, we did observe enhanced skin colonization in one of two virus-infected M. sympodialis strains. Noteworthy, beta interferon expression was significantly upregulated in bone marrow-derived macrophages when challenged with virus-infected, compared to virus-cured, M. sympodialis, suggesting that the presence of the virus can induce an immunological response. Although many recent studies have illuminated how widespread mycoviruses are, there are relatively few in-depth studies about their impact on disease caused by the host fungus. We describe here a novel mycovirus in Malassezia and its possible implications in pathogenicity.

中文翻译：

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一种新型的分枝杆菌病毒在真菌马拉色菌中引起转录重排，并刺激巨噬细胞中的β干扰素产生。

霉菌病毒感染真菌，尽管大多数无症状，但仍有一些霉菌病毒对其宿主产生有益和有害作用的例子。病毒感染的酿酒酵母和Ustilago菌株表现出杀手表型，与未感染的菌株和其他竞争性酵母菌种相比具有生长优势，而被低毒病毒感染的Cryphonectria parasitica则表现出生长，孢子形成和毒力方面的缺陷。在这项研究中，我们确定了五个马拉色菌中的双链RNA（dsRNA）分支病毒种类。序列分析显示它是一种带有两个dsRNA片段的轮状病毒：一个较大的4.5 kb片段，带有编码病毒复制和维持成分的基因，一个较小的1.4 kb片段，编码新蛋白质。此外，病毒感染与病毒治疗的马拉塞斯霉共生菌的转录组测序（RNA-seq）显示出细胞中数十种核糖体成分的上调，表明该病毒修饰了细胞的转录和翻译环境。鉴于马拉色西亚霉菌是人类皮肤上最丰富的真菌，我们评估了分枝杆菌病毒在鼠表皮感染模型中的影响。尽管用病毒感染的菌株感染与炎症反应增加无关，但我们确实观察到在两种病毒感染的S. sympodialis菌株之一中皮肤定植增强。值得注意的是，与病毒治疗的交感支原体相比，β-干扰素的表达在被病毒感染的骨髓来源的巨噬细胞中显着上调。，表明该病毒的存在可以诱导免疫反应。尽管最近的许多研究阐明了分枝杆菌病毒的广泛传播，但有关其对宿主真菌引起的疾病影响的深入研究相对较少。我们在这里描述一种在马拉色菌中的新型分枝杆菌病毒及其对致病性的潜在影响。