Molecular characterization of a novel hypovirus from the plant pathogenic fungus Fusarium graminearum

Abstract

A novel mycovirus, termed Fusarium graminearum Hypovirus 2 (FgHV2/JS16), isolated from a plant pathogenic fungus, Fusarium graminearum strain JS16, was molecularly and biologically characterized. The genome of FgHV2/JS16 is 12,800 nucleotides (nts) long, excluding the poly (A) tail. This genome has only one large putative open reading frame, which encodes a polyprotein containing three normal functional domains, papain-like protease, RNA-dependent RNA polymerase, RNA helicase, and a novel domain with homologous bacterial SMC (structural maintenance of chromosomes) chromosome segregation proteins. A defective RNA segment that is 4553-nts long, excluding the poly (A) tail, was also detected in strain JS16. The polyprotein shared significant aa identities with Cryphonectria hypovirus 1 (CHV1) (16.8%) and CHV2 (16.2%). Phylogenetic analyses based on multiple alignments of the polyprotein clearly divided the members of Hypoviridae into two major groups, suggesting that FgHV2/JS16 was a novel hypovirus of a newly proposed genus-Alphahypovirus-composed of the members of Group 1, including CHV1, CHV2, FgHV1 and Sclerotinia sclerotiorum hypovirus 2. FgHV2/JS16 was shown to be associated with hypovirulence phenotypes according to comparisons of the biological properties shared between FgHV2/JS16-infected and FgHV2/JS16-free isogenic strains. Furthermore, we demonstrated that FgHV2/JS16 infection activated the RNA interference pathway in Fusarium graminearum by relative quantitative real time RT-PCR.

Novel, diverse RNA viruses from Mediterranean isolates of the phytopathogenic fungus, Rosellinia necatrix: insights into evolutionary biology of fungal viruses

“…This D‐RNA was constantly detected in the fungal strain, appearing to be stably maintained. This detection profile was very similar to that for the JS16 strain of F. graminiarum (Li et al ., ) which harbors the Fusarium graminiarum hypovirus (FgHV1) dsRNA of 12.8 kbp and its D‐RNA RF of 5 kbp.…”

Comparative Analysis of the Composition and Active Property Evaluation of Certain Essential Oils to Assess their Potential Applications in Active Food Packaging

“…This pathogen has the potential to produce mycotoxines (deoxynivalenol and zearalonene) that have a negative impact on human and animal health [45]. The contamination of cereals by this toxigenic mold produces major economic impacts in agriculture.…”

Complete Genome Sequence of a Novel Hypovirus from the Phytopathogenic Fungus Fusarium langsethiae

“…Multiple alignments and phylogenetic analyses of the viral polyproteins and the conserved domain (RdRp and Hel) aa sequences using the neighbor-joining method revealed that FlHV1 formed a well-supported phylogenetic branch together with FgHV2 and FpHV1, and was grouped in a big clade, Alphahypovirus , including Cryphonectria hypovirus 1 (CHV1), CHV2, FgHV1, FgHV2, FpHV1, and Sclerotinia sclerotiorum hypovirus 2 (SsHV2). Although Hu et al and Khalifa and Pearson have suggested that a third distinct genus, Gammahypovirus should be located in the family Hypoviridae (5, 6), the isolation of an increasing number of novel hypoviruses will support the suggestion that the members of Hypoviridae are divided into two major groups: Alphahypovirus and Betahypovirus , as Li et al (3) and Yaegashi et al (9) have described.…”

“…Mycoviruses of the family Hypoviridae , which do not produce true virions or encode capsid proteins, have monopartite ssRNA genomes ranging from 9 to 13 kb in size (1, 2). Twelve reported virus species within the family Hypoviridae were isolated from six plant pathogenic fungi: Cryphonectria parasitica , Sclerotinia sclerotiorum , Fusarium graminearum , F. poae , Valsa ceratosperma , and Phomopsis longicolla (3, 4). Li et al (3) proposed that the family Hypoviridae should contain two genera: Alphahypovirus and Betahypovirus , instead of three genera (3, 5, 6).…”