title: Multiple introductions and recombination in Cryphonectria hypovirus 1: perspective for a sustainable biological control of chestnut blight.
abstract: Cryphonectria hypovirus 1 (CHV1) is a mycovirus which decreases the virulence of its fungal host Cryphonectria parasitica, the causal agent of chestnut blight recently introduced in Europe. The understanding of the evolutionary processes which have shaped CHV1 populations in Europe is required to develop a sustainable biocontrol strategy targeting chestnut blight and effective in European chestnut forests. To retrace the evolutionary history of CHV1, we analyzed sequences from two genomic regions on a collection of 55 CHV1 strains from France and northern Spain, two countries where multiple introductions of C. parasitica occurred. Several recombination events and variable selection pressures contributed to CHV1 evolution, agreeing with a non-clock-like diversification rate. These two mechanisms may be at the origin of CHV1 population diversity observed in western Europe. Considering the actual prevalence of CHV1 and its association with host genotypes, multiple introductions of CHV1 may have occurred in Europe, some of them directly from Asia and some of them through North America. Although some viral strains remained with low frequency in their introduction area, multiple infections might have allowed homologous recombination within parental sequences. Some of these recombinant lineages are associated with the spread of CHV1 in European regions.
authors.affiliation: INRA, UMR1202 BIOGECO F-33610, Cestas, France ; University Bordeaux, BIOGECO, UMR 1202 F-33400, Talence, France ; TAIGA-Lab, Forest Sciences Centre, University of British Columbia #3618-2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Feau
authors.affiliation: INRA, UMR1202 BIOGECO F-33610, Cestas, France ; University Bordeaux, BIOGECO, UMR 1202 F-33400, Talence, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Dutech
authors.affiliation: INRA, UMR1202 BIOGECO F-33610, Cestas, France ; University Bordeaux, BIOGECO, UMR 1202 F-33400, Talence, France ; Department of Ecology and Evolutionary Biology, Earth and Marine Sciences Building, University of California Santa Cruz, CA, 95064, USA.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Brusini
authors.affiliation: WSL Swiss Federal Research Institute CH-8903, Birmensdorf, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rigling
authors.affiliation: INRA, UMR1202 BIOGECO F-33610, Cestas, France ; University Bordeaux, BIOGECO, UMR 1202 F-33400, Talence, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Robin
keywords: biological control; disease biology; host parasite interactions; invasive species; microbial biology