Molecular Characterization of Fusarium Graminearum Virus 2 Isolated from Fusarium graminearum Strain 98-8-60

Yu, Ji Suk; Lee, Kyung Mi; Son, Moon Il; Kim, Kook Hyung

The Plant Pathology Journal 2011;27(3):285-290.
Published online September 30, 2011.

Molecular Characterization of Fusarium Graminearum Virus 2 Isolated from Fusarium graminearum Strain 98-8-60

Ji Suk Yu, Kyung Mi Lee, Moon Il Son, Kook Hyung Kim

Abstract

Fusarium graminearum virus 2 (FgV2) infects Fusarium graminearum strain 98-8-60 and has at least five segments of double-stranded RNAs (dsRNAs), denoted as dsRNA-1 to dsRNA-5. In this study, the genome of FgV2 was sequenced and its phylogenetic relationship with other mycoviruses was analyzed. The lengths of FgV2 dsRNAs 1-5 ranged from 2414 to 3580 base pairs (bp). The 5` and 3` untranslated regions (UTRs) are highly conserved, and each dsRNA segment had 78-105 and 84-306 bp of 5` and 3` UTRs, respectively. Each dsRNA segment contained a single open reading frame (ORF). Computer analysis of dsRNA-1 revealed a putative open reading frame (ORF) that shows high sequence identity with an RNA-dependent RNA polymerase (RdRp) containing eight conserved motifs. dsRNAs 2-5 also each contain one putative ORF coding for products of unknown function. The sequences of FgV2 dsRNA-2 and dsRNA-3 have significant sequence identity with Magnaporthe oryzae chrysovirus 1 (MoCV1) dsRNA-3 and -4, respectively. When compared to other dsRNA mycoviruses in a phylogenetic analysis of the putative RdRp protein, FgV2 was found to form a distinct virus clade with Aspergillus mycovirus 1816 and MoCV1 in the family Chrysoviridae.

Key Words: Chrysoviridae, Fusarium graminearum virus 2, Mycovirus