Identification and partial characterization of Taastrup virus: a newly identified member species of the Mononegavirales.

We present a 8904-nt sequence of the central part of the RNA genome of a novel virus with a filovirus-like, nonidentical morphology named Taastrup virus (TV) detected in the leafhopper Psammotettix alienus. Sequence analysis identified five potential open reading frames (ORFs) and a complex pattern of homologies to various members of the Mononegavirales suggests a genome organization with the following order of genes: 3'-N-P-M-G-L-5'. Sequence analyses reveal an unusually large glycoprotein (G) containing both potential O-linked (14) and N-linked (9) glycosylation sites-a feature shared with the glycoproteins of Filoviridae and Pneumovirinae, and a nucleoprotein (N) with homology to the nucleoprotein of viral hemorrhagic septicemia virus (VHSV), a member of the Rhabdoviridae. Highly conserved domains were identified in the RNA-dependent RNA polymerase (L) between TV and other viruses within the order of Mononegavirales, and homology was found in particular with members of the Rhabdoviridae. The sequence similarities and the unique filovirus-like but nonidentical morphology unambiguously refer this newly identified virus to the order of Mononegavirales but to no family more than any, to other within the order.

Filovirus-like particles detected in the leafhopper Psammotettix alienus.

Filamentous particles were detected by negative contrast electron microscopy of extracts from the leafhopper Psammotettix alienus (Dahlbom) reared on healthy Festuca gigantea plants. The particles were straight, slightly curved or flexuous, sometimes with the one end curled into a ring with an outer diameter of about 200 nm. Length distribution of 280 particles showed a minor and a major group with median length of about 600 and 1,100 nm, respectively. Projections, 8-10 nm long and about 10 nm apart, were evenly distributed on the surface. The diameter of particles, including projections, was 55-70 nm. Partly disintegrated revealed an internal structure about 30 nm in diameter and with cross-striation with a periodicity of 5-5.5 nm. In some particles, a central canal, 5-10 nm in diameter, could be seen at one end. Ultramicrotomy of leafhopper heads showed that some cells contained intracytoplasmic clusters of particles together with filamentous structures. The particles described in this paper resemble virions in the virus family Filoviridae, but can be distinguished by having a smaller particle diameter. The name Taastrup virus is suggested for the putative virus from Psammotettix alienus, according to the place it was first detected.

Comparison of Festuca leaf streak virus antigens with those of three other rhabdoviruses infecting the Gramineae.

Leaf tissue from plants infected with Festuca leaf streak virus was extracted with a buffer containing a nonionic detergent; this treatment released the G protein from the nucleocapsid of virions. The extract was tested with antiserum by double immunodiffusion for G protein and by immunosorbent electron microscopy with 'decoration' for nucleocapsid antigens. Clear homologous reactions were obtained. No heterologous reactions were observed with similar preparations of barley yellow striate mosaic, northern cereal mosaic, and cereal chlorotic mottle viruses.