Furovirus

Abstract

Furoviruses are plant viruses with rod-shaped nonenveloped particles which contain a single coat protein species of c . 20 kDa. In freshly infected field grown plants the predominant lengths of the particles are c . 140–160 and 280–300 nm. Furoviruses have bipartite genomes consisting of linear positive-sense ssRNAs with 3′-terminal valine-specific tRNA-like structures. In nature furoviruses are transmitted by the zoospores of Polymyxa graminis which carry the viruses internally, possibly not in form of their virions but rather of RNA-movement protein complexes. There are no indications that furoviruses multiply in their vector. In the long-living resting spores of the vector they can survive for many years even under extreme conditions and can be spread on agricultural equipment, by irrigation and even by wind blow. Presently, the genus Furovirus comprises five species, namely Soil-borne wheat mosaic virus , Soil-borne cereal mosaic virus, Chinese wheat mosaic virus, Oat golden stripe virus, and Sorghum chlorotic spot virus . These viruses all cause severe diseases in their hosts which, like all other Polymyxa -transmitted virus diseases, are difficult to control. Growing resistant or tolerant varieties is the most effective means to lower their impact on yield. Genes conferring complete immunity to these viruses have so far not been found.