A NEW VIRUS ISOLATED FROM AN ASH TREE WITH DIEBACK

A virus isolated from an ash tree with die-back has icosahedral virion s c. 28 nm in diameter which contain a polyadenlyated and infectious b ipartite single stranded RNA genome. The RNAs have M. Wts of c. 2.4 an d 2.6 X 10(6). The virus was transmitted in 5/48 seed from infected Ch enopodium quinoa. Serological tests failed to detect any relationships with 10 viruses. cDNA to the viral RNA was cloned. The sequences of t he 5' and 3' ends of two clones were determined. One of these clones r epresents the 3'-terminus of one of the viral genomic fragments. A sea rch of nucleic acid sequence databases showed some similarity of the 3 '-terminal sequence of the virus to the 3'-terminal sequence of cowpea mosaic virus. The virus is possibly a previously undescribed nepoviru s or comovirus.