engleski

Sequence Analysis of Cryphonectria hypovirus 1 in Croatia

Cryphonectria hypovirus 1 (CHV1) is an RNA mycovirus that infects the chestnut blight fungus Cryphonectria parasitica. CHV1 infection reduces virulence of C. parasitica towards chestnut trees and causes recovery . It is assumed that CHV1 was introduced together with its host to Europe from Asia and then spread throughout C. parasitica populations. CHV1 may be transmitted horizontally from one fungal individual to another via hyphal anastomosis and vertically through asexual conidia. Several genetically distinct subtypes of CHV1 occur in Europe, but Italian subtype is the most widespread, probably due to a better ecological fitness. In this study we analyzed C. parasitica isolates from Croatian chestnut populations which produced white mycelium with reduced sporulation, characteristic for C. parasitica isolates infected with CHV1 (hypovirulent isolates). The presence of hypoviral RNA was confirmed in all isolates and part of the CHV1 genome of these hypovirulent C. parasitica isolates was sequenced. The length of analysed sequences was 1249 bp. All sequences of hypoviruses from Croatia clustered together with reference sequences of Italian subtype from GenBank and were clearly separated from the other CHV1 subtypes which indicates that all CHV1 strains from this study belong to the Italian subtype of CHV1. However, high number of different haplotypes were detected among hypoviral sequences suggesting the high diversity of CHV1 in Croatia.

CHV1; mutation; population structure

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