Mark Stevens1, Benjamin Freeman1, Hsing-Yeh Liu2, Etienne Herrbach3 and Olivier Lemaire3
1 Broom’s Barn Research Station, Higham, Bury St Edmunds, Suffolk IP28 6NP, UK
2 USDA-ARS, 1636 E. Alisal Street, Salinas, CA 93905, USA
3 INRA, UR-BIVV, 28 rue de Herrlisheim, 68021 Colmar, France
| Taxonomy: | There are three members of the genus Polerovirus (family Luteoviridae) that induce yellowing of sugar beet: Beet mild yellowing virus (BMYV), Beet chlorosis virus (BChV) and Beet western yellows virus-USA (BWYV-USA). Non-beet-infecting isolates of BWYV found particularly within Europe have now been re-named Turnip yellows virus (TuYV). Species-specific antibodies are unavailable, but the viruses can be distinguished by RT-PCR using primers specifically designed to the 5′ end of their respective genomes. |
| Physical properties: | The isometric virus particles are approximately 26 nm in diameter and the genome consists of a single strand of positive sense RNA that utilizes almost all known plant virus gene expression strategies (initiation bypass, translational frameshifting and readthrough, synthesis of subgenomic RNA and proteolytic processing). |
| Host range: | Many members of the Chenopodiaceae are susceptible, including commercial crops of sugar beet (Beta vulgaris), red beet and spinach. Experimental hosts include Montia perfoliata, Nicotiana benthamiana and Arabidopsis thaliana. |
| Symptoms: | Sugar beet infected with beet poleroviruses show patches of chlorosis on the older leaves 6 weeks post-infection; these areas expand until the whole leaf becomes yellow and older leaves then tend to thicken and become brittle. |
| Transmission: | Beet poleroviruses are transmitted in a persistent (circulative, non-propagative) manner by several different aphid species, Myzus persicae being the most important vector. |
