Abstract

A total of 30 hypovirus isolates (CHV1) of Cryphonectria parasitica from China, Japan, and Italy were analyzed by partial nucleotide measurement for ORF A in the virus genome to reveal the origin of CHV1 in Europe. By partial nucleotide measurement, these viruses can be divided into 29 different haplotypes, which group into three subtypes. The viruses from China belong to subtypesⅠand Ⅲ, whereas the viruses from Japan belong to subtype Ⅱ except for Ja55 of subtype Ⅲ, and the viruses from Italy were of subtype Ⅲ except for IT192 belonging to subtypeⅠ. SubtypesⅠand Ⅲ are widely distributed in China whereas in Europe only one subtype is spread widely. SubtypeⅠviruses in southern China are bounded by the Yangtze River except isolates 09228 and 09235 from Beijing and 09277 from Liaoning Province, whereas subtype Ⅲ viruses occurred in northern China except for isolate 09344 from Hunan Province. The results suggest that gene flow occurred among the hypovirus populations and also revealed greater diversity in CHV1 populations from China than in those from Japan and Italy.