Buma Seiji, Urayama Syun-Ichi, Suo Rei, Itoi Shiro, Okada Shigeru, Ninomiya Akihiro
Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan; College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan.
Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan; Microbiology Research Center for Sustainability, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan.
Virus Res. 2024 Dec;350:199470. doi: 10.1016/j.virusres.2024.199470. Epub 2024 Oct 2.
Fungi are exploited for fermentation of foods such as cheese, Japanese sake, and soy sauce. However, the diversity of viruses that infect fungi involved in food fermentation is poorly understood. Fermented dried bonito ("katsuobushi") is one of the most important processed marine products in Japan. Fungi involved in katsuobushi fermentation are called katsuobushi molds, and Aspergillus spp. have been reported to be dominant on the surface of katsuobushi during fermentation. Because various mycoviruses have been found in members of the genus Aspergillus, we hypothesized that katsuobushi molds are also infected with mycoviruses. Here, we describe seven novel mycoviruses belonging to six families (Chrysoviridae, Fusariviridae, Mitoviridae, Partitiviridae, Polymycoviridae, and Pseudototiviridae) from isolated katsuobushi molds (Aspergillus chevalieri and A. sulphureus) detected by fragmented and primer-ligated double-stranded RNA sequencing. Aspergillus chevalieri fusarivirus 1 has a unique bi-segmented genome, whereas other known fusariviruses have a single genomic segment. Phenotypic comparison between the parental A. chevalieri strain infected with Aspergillus chevalieri polymycovirus 1 (AchPmV1) and isogenic AchPmV1-free isolates indicated that AchPmV1 inhibits the early growth of the host. This study reveals the diversity of mycoviruses that infect katsuobushi molds, and provides insight into the effect of mycoviruses on fungi involved in fermentation.
真菌被用于食品发酵，如奶酪、日本清酒和酱油。然而，人们对感染参与食品发酵的真菌的病毒多样性了解甚少。发酵鲣鱼干（“柴鱼”）是日本最重要的加工海产品之一。参与柴鱼发酵的真菌被称为柴鱼霉菌，据报道，曲霉属在发酵过程中是柴鱼表面的优势菌属。由于在曲霉属成员中发现了多种真菌病毒，我们推测柴鱼霉菌也感染了真菌病毒。在此，我们描述了通过片段化和引物连接双链RNA测序从分离的柴鱼霉菌（谢瓦氏曲霉和硫黄曲霉）中检测到的属于六个科（金黄病毒科、镰刀菌病毒科、线粒体病毒科、分病毒科、多真菌病毒科和假总病毒科）的七种新型真菌病毒。谢瓦氏曲霉镰刀菌病毒1具有独特的双片段基因组，而其他已知的镰刀菌病毒具有单个基因组片段。对感染谢瓦氏曲霉多真菌病毒1（AchPmV1）的亲本谢瓦氏曲霉菌株和同基因无AchPmV1分离株进行表型比较，结果表明AchPmV1抑制宿主的早期生长。这项研究揭示了感染柴鱼霉菌的真菌病毒的多样性，并深入了解了真菌病毒对参与发酵的真菌的影响。
