Neo-lifestyle of fungal viruses

2020 Fiscal Year Final Research Report

• Project Area: Neo-virology: the raison d'etre of viruses
• Project/Area Number: 16H06436
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: Okayama University
• Principal Investigator: Suzuki Nobuhiro 岡山大学, 資源植物科学研究所, 教授 (70206514)
• Co-Investigator(Kenkyū-buntansha): 近藤 秀樹 岡山大学, 資源植物科学研究所, 准教授 (40263628)
• Project Period (FY): 2016-06-30 – 2021-03-31
• Keywords: 植物病原糸状菌 / ネオライフスタイル / 宿借性 / マイコウイルス / yadonushi virus / 宿主性 / 裸性 / yadokari virus

Outline of Final Research Achievements

The objective of this project is to establish two neo-lifestyles of fungal viruses and explore their generality and ecological significance. First, we have proved the yadokari/ yadonushi nature in Japanese strains of Rosellinia necatrix and revealed its molecular basis. Capsidless yadokari virus 1 (YkV1) highjacks the capsid of yadnushi virus 1 (YnV1) to replicate in the heterocapsid using its own RNA-dependent RNA polymerase, while in return YkV1 trans-enhances the replication of YnV1. For the hadaka nature, we have shown that hadaka virus 1 (HadV1) from a Pakistani strain of Fusarium oxysporum exists as a capsidless naked form at least in mycelial homogenates that is accessible by RNase A and unable to be pelleted by untracentrifugation. While the yadonushi/yadokari nature has been observed not only foreign fungal strains but also in plants,the hadaka nature has also been detected in other filamentous fungi, suggesting suggesting the generality of the two viral neo-lifestyles.

Free Research Field

植物病理学

Academic Significance and Societal Importance of the Research Achievements

ウイルス学の常識を覆す新しいウイルスライフスタイル２つを確立した本研究は、他の真核生物を宿主とするウイルス研究に大きな衝撃をもたらした。宿借・宿主性を示した論文は、Nature Reviews Microbiologyで取り上げられた。一方、裸性を示すハダカウイルスは、進化学的に１本鎖RNAウイルスと２本鎖RNAウイルスとの親和性を持つことから大きな注目を集めている。現在、国際ウイルス分類委員会で熱い議論を巻き起こしている。