Partial characterization of Bermuda grass mosaic virus, a tentative member of the family Potyviridae.

Mosaic symptoms were seen on Bermuda grass (Cynodon dactylon (L.) Pers.) in many parts of Iran. Examination by electron microscopy of samples from diseased plants revealed elongated filamentous virus particles. The virus was mechanically transmitted to some Gramineous plants. Virions of a two isolates of this virus were purified from Goose grass and also from field-infected Bermuda grass. Virus-specific polyclonal antibodies were prepared in rabbits for use in studying serological relationships, by SDS-immunodiffusion tests and immunosorbent electron microscopy. No serological relationships were demonstrated between all virus isolates and some members of the family Potyviridae, including Johnson grass mosaic virus, Maize dwarf mosaic, Sorghum mosaic, Sugarcane mosaic, Wheat streak mosaic viruses in plate-trapped antigen enzyme linked immunosorbent assay (ELISA). The virus did not react to potyvirus group antiserum in serological assays. Polymerase Chain reaction (RT-PCR) assay using potyvirus degenerate primers confirmed the serological results. General primers derived from Nib region of potyvirids genome were used in a reverse transcription-polymerase chain reaction (RT-PCR) assay and gave an expected amplification product of 1700 bp similar to other Potyviridae members. The PCR product was cloned and sequenced. The predicted amino acid sequence corresponds to part of the nuclear inclusion b (NIb) protein and the capsid protein (CP), followed by an untranslated region and a polyadenylated tail at the 3 end. The most similar sequence in the databases was that of Spartina mottle virus, a non assigned member of family Potyviridae. The sequence had 76 % nt identity to Spartina mottle virus in the 3́-terminal 1700 bp nucleotide sequence of the RNA genome. Serological and sequence comparisons suggest that the Bermuda grass filamentous virus should be regarded as a new species of the family Potyviridae, and we have tentatively named it Bermuda grass mosaic virus.