First detection and partial characterization of a furovirus isolated from winter barley in Germany
The yellow mosaic virus complex of winter barley which is caused by the two bymoviruses Barley mild mosaic virus (BaMMV) and Barley yellow mosaic virus (BaYMV), is one of the most severe threats to the crop growing of winter barley in Germany. Other soil-borne cereal viruses like Soil-borne cereal mosaic virus (SBCMV) or Soil-borne wheat mosaic virus (SBWMV) also transmitted by Polymyxa graminis and infecting wheat, rye and triticale have never been observed up to now on winter barley under field conditions in Germany. However field examinations of yellow mosaic virus resistant barley genotypes has shown that plants carrying mosaic symptoms contained rod-shaped virus particles. Several isolates were obtained by mechanical inoculation of test plants and one isolate originating from variety ’Jorinde’ (harbouring the rym5 resistance gene) was designated as Jorinde-1 and was further characterized. The biological, serological and molecular data obtained so far indicate that the German isolate Jorinde-1 belongs to the genus Furovirus and is closely related to Japanese SBWMV (JT) and the French Soil-borne barley mosaic virus (SBBMV, later renamed as SBWMV-Mar). Phylogenetic analysis by means of sequencing data for RNA2 coding for cistrons of coat protein, read through protein and cysteine rich protein revealed that Jorinde-1, SBBMV and SBWMV (JT) form a separate cluster and may represent a new species in the genus Furovirus within the family Virgaviridae.