title: 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.
authors.affiliation: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Li
authors.affiliation: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China.
authors.forename: Hailong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China.
authors.forename: Dewen
authors.initials: D
authors.lastname: Qiu
authors.affiliation: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China. Electronic address: guolihua72@yahoo.com.
authors.forename: Lihua
authors.initials: L
authors.lastname: Guo
mesh_terms: D000595:Amino Acid Sequence; D005670:Fusarium / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D016679:Genome, Viral; D008969:Molecular Sequence Data; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D020815:Polyproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012328:RNA Viruses / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D016415:Sequence Alignment; D014908:Triticum / Q000382:microbiology*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D020815:Polyproteins; D014764:Viral Proteins
keywords: FgHV2; Fusarium graminearum; Fusarium head blight; Hypoviridae; Mycovirus; dsRNA