Buma Seiji, Urayama Syun-Ichi, Tomita Kenji, Oiki Sayoko, 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.
Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan.
Arch Virol. 2025 Jun 3;170(7):147. doi: 10.1007/s00705-025-06333-2.
Fungi are frequently infected with viruses called mycoviruses. Some mycoviruses have shown potential as biocontrol agents because they can weaken the virulence of fungal plant pathogens. Intensive research has been conducted on the diversity of viruses infecting plant pathogens and the functions of such viruses. In contrast, the diversity of viruses infecting fungi that are not plant pathogens is less well understood. We previously identified a mycovirus of the family Partitiviridae, Aspergillus sulphureus partitivirus 1 (AsuPV1), from an Aspergillus sulphureus strain isolated from fermented dried bonito. In the present study, we conducted a detailed phylogenetic analysis of AsuPV1 and determined its molecular characteristics. The phylogenetic analysis revealed that AsuPV1 belongs to the proposed subgroup I within the genus Gammapartitivirus. Virus particles of AsuPV1 were isolated by density gradient centrifugation, and molecular analyses indicated that each of its three genome segments is encapsulated in capsids composed of the putative viral coat protein. AsuPV1 is the second virus with a tri-segmented genome to be found in a member of Gammapartitivirus subgroup I, after Penicillium stoloniferum virus F. A phenotypic comparison between the parental A. sulphureus strain and isogenic virus-free isolates indicated that AsuPV1 enhances conidium production in its host. This study provides insight into the diversity and molecular characteristics of partitiviruses with a tri-segmented genome.
真菌经常感染被称为真菌病毒的病毒。一些真菌病毒已显示出作为生物防治剂的潜力，因为它们可以削弱植物病原真菌的毒力。人们对感染植物病原体的病毒多样性及其功能进行了深入研究。相比之下，感染非植物病原真菌的病毒多样性则了解较少。我们之前从发酵鲣鱼干中分离出的一株硫黄曲霉中鉴定出一种分节段病毒科的真菌病毒，即硫黄曲霉分节段病毒1（AsuPV1）。在本研究中，我们对AsuPV1进行了详细的系统发育分析，并确定了其分子特征。系统发育分析表明，AsuPV1属于γ分节段病毒属中提议的亚组I。通过密度梯度离心法分离出了AsuPV1的病毒粒子，分子分析表明其三个基因组片段中的每一个都被包裹在由推定的病毒衣壳蛋白组成的衣壳中。AsuPV1是在γ分节段病毒亚组I成员中发现的第二种具有三分节基因组的病毒，仅次于匐枝青霉病毒F。对亲本硫黄曲霉菌株和同基因无病毒分离株的表型比较表明，AsuPV1可提高其宿主中分生孢子的产量。本研究为具有三分节基因组的分节段病毒的多样性和分子特征提供了见解。
