Description and prevalence of a putative novel mycovirus within the conifer pathogen Gremmeniella abietina

9 Pág

The European race of Gremmeniella abietina (Lagerberg) Morelet is the causal agent of stem canker and shoot blight on numerous conifers in Europe and North America. It comprises different species and biotypes in which the presence of mycoviruses has been determined. In this report, we describe the full-length sequence of the RNA-dependent RNA polymerase (RdRp) of a putative novel virus, Gremmeniella abietina RNA virus 6 (GaRV6), with 2165 nt and a GC content of 54.7 %. A BLASTp search using the deduced RdRp amino acid sequence confirmed GaRV6 to be related to members of a still unassigned virus taxon, which includes, e.g., Fusarium graminearum dsRNA mycovirus 4 (FgV-4) and the mutualistic Curvularia thermal tolerance virus (CThTV). The prevalence and genetic diversity of GaRV6 was also studied within the European race of G. abietina. We examined 162 isolates originating from Canada, the Czech Republic, Finland, Italy, Montenegro, Serbia, Spain, Switzerland, Turkey and the United States. According to direct specific reverse transcription (RT) PCR screening based on the RdRp sequence, the virus appears to be present only in Spain, where it is relatively abundant but genetically highly uniform.

This research was developed in the Czech Republic thanks to the projects OPVK “PhD researchers in the field of technical and economic sciences at MENDELU” (CZ.1.07/2.3.00/30.0017) and “Indicators of tree vitality” (CZ.1.07/2.3.00/20.0265), both supported by the OP Education for Competitiveness, the European Social Fund and the Czech Ministry of Education, Youth and Sport. However, it was started in Finland, thanks to a Ph.D. Grant from the University of Valladolid, and the project AGL2008-03622 of the Ministry of Culture and Science (Spain). EJV and JH received financial support from the Academy of Finland (Decision Numbers 251193 and 258520).

Peer reviewed