Barley yellow dwarf viruses
Author: Keith Weller
Source: Wikimedia Commons
Barley yellow dwarf viruses (BYDVs)
Yellow dwarf diseases of barley and other cereals are caused mainly by viruses from the genus Luteovirus (family Tombusviridae). They are widespread and are serious constraints in cereals like wheat, barley, oat or maize. These diseases are transmitted by cereal aphids in a circulative and persistent manner. They where originally thought to be caused by a single virus, the "barley yellow dwarf virus". In the 1960s different serotypes of this virus were described, which were named after the main aphid vectors transmitting them. For example, a common type transmitted mainly by the aphids Rhopalosiphum padi and Sitobion avenae was named 'barley yellow dwarf virus PAV'. Molecular analyses later revealed that these serotypes were actually separate viruses, now assigned to different species. Many of them belong to the genus Luteovirus, but some of them were assigned to the genus Polerovirus (family Solemoviridae) and renamed like the cereal yellow dwarf viruses or the 'maize yellow dwarf virus RMV' (Krueger et al., 2013). Still others, like the 'barley yellow dwarf virus-SGV', have not yet been assigned to a genus, but are also known to belong to the family Solemoviridae (not the Tombusviridae).
| Vernacular names | |
|---|---|
| • Deutsch: | Gerstengelbverzwergungs-Virus Gelbverzwergung der Gerste |
| • English: | barley yellow dwarf virus rice galliume virus |
| • Español: | raquitisimo amarillo de la cebada |
| • Français: | jaunisse nanisante de l'orge |
The symptoms caused by BYDV viruses include stunting and chlorosis which starts at the edges and tips, then spreading over the whole leaf. The leaves become bright yellow (barley) or orange (oat). Seed production is reduced, resulting in major yield losses, especially in oats. E.g. in North America, wheat losses by these viruses in combination with the aphid vectors have been estimated at up to 30-40%.
Certain aphids transmit the viruses in autumn to winter cereals, and again in spring from winter cereals to summer cereals as well as to maize. The diseases have an incubation period of 2-4 weeks, they can be managed by using resistant cultivars. Virus particles are hexagonal, 25-28 nm in diameter, with a single-stranded RNA. They are found in the phloem cells of the host plant.
The following viruses are currently entered into the system under the barley yellow dwarf virus complex:
