The European chestnut (Castanea sativa Mill.) agro‐ecosystem has been of high social,
economic, and landscape importance in Portugal. Chestnut blight caused by the fungus
Cryphonectria parasitica is considered a major cause of the decline of chestnut trees
across Europe. C. parasitica is an ascomycete (Diaporthales) that is native to eastern Asia.
Infection of chestnut trees with this pathogen is typically associated with extensive bark
necrosis (so‐called cankers) on stems and branches, resulting in the subsequent death of
the part of the tree above the infection point. Chestnut blight in Portugal was first
reported in 1992 and since expanding in distribution. Here, we investigated the invasion
history of C. parasitica and its associated hypovirus in Portugal. For this, we characterized
137 isolates collected between 2013 and 2014 in four chestnut stands for virus‐infection,
vegetative compatibility (vc) type, mating type and microsatellite haplotype. A total of 33
haplotypes and four vc types were observed, although the Portuguese C. parasitica
population is currently dominated by a single haplotype and a single vc type (EU‐11).
Further diversification may be expected due to ongoing sexual recombination, but
eventually also to new migration and additional introductions. Cryphonectria hypovirus 1
(CHV‐1) was found in two populations. Genetic analysis of the six CHV‐1 isolates obtained
revealed that three viral strains belong to the Italian subtype and three to the French
subtype, which suggest different, independent introductions.info:eu-repo/semantics/publishedVersio
