Capsid structure of a fungal dsRNA megabirnavirus reveals its previously unidentified surface architecture

• Published in: PLoS pathogens Vol. 19; no. 2; p. e1011162
• Main Authors: Wang, Han, Salaipeth, Lakha, Miyazaki, Naoyuki, Suzuki, Nobuhiro, Okamoto, Kenta
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27.02.2023; Public Library of Science (PLoS)
• Subjects: Amino acids; Atomic structure; Biology and Life Sciences; Capsid - chemistry; Capsid protein; Capsid Proteins - chemistry; Capsid Proteins - genetics; Causes of; Comparative analysis; Cryoelectron Microscopy; Double-stranded RNA; Electron microscopy; Fungal diseases of plants; Fungi; Fungi, Phytopathogenic; Genetic aspects; Genomes; Medicine and Health Sciences; Physiological aspects; Plant diseases; Protein structure; Proteins; Research and Analysis Methods; RNA polymerase; RNA viruses; RNA Viruses - genetics; RNA, Double-Stranded - genetics; Root rot; Rosellinia necatrix; Structure; Symmetry; Viral proteins; Virulence; Viruses; Sweden
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1011162

Rosellinia necatrix megabirnavirus 1-W779 (RnMBV1) is a non-enveloped icosahedral double-stranded (ds)RNA virus that infects the ascomycete fungus Rosellinia necatrix, a causative agent that induces a lethal plant disease white root rot. Herein, we have first resolved the atomic structure of the RnMBV1 capsid at 3.2 Å resolution using cryo-electron microscopy (cryo-EM) single-particle analysis. Compared with other non-enveloped icosahedral dsRNA viruses, the RnMBV1 capsid protein structure exhibits an extra-long C-terminal arm and a surface protrusion domain. In addition, the previously unrecognized crown proteins are identified in a symmetry-expanded cryo-EM model and are present over the 3-fold axes. These exclusive structural features of the RnMBV1 capsid could have been acquired for playing essential roles in transmission and/or particle assembly of the megabirnaviruses. Our findings, therefore, will reinforce the understanding of how the structural and molecular machineries of the megabirnaviruses influence the virulence of the disease-related ascomycete fungus.