Aphids vary in their ability to transmit an important cereal virus; however, the underlying processes are unclear. Here three mechanisms that potentially explain this variation are proposed.

Abstract

Cereals are some of the most important global crops that contribute directly and indirectly to the production of food for human consumption. Cereal aphids can cause significant damage to wheat, barley and oats, particularly via the transmission of plant viruses that cause devastating plant diseases, such as yellow dwarf disease. High levels of yellow dwarf disease can result in yield losses of around 20%, rising to 80% if infection is severe. Yellow dwarf disease is caused by multiple viruses, including viruses within the families Tombusviridae and Solemoviridae. These include yellow dwarf virus species within the genus Luteovirus (Barley yellow dwarf virus) and Polerovirus (Cereal yellow dwarf virus, Wheat yellow dwarf virus, Maize yellow dwarf virus). Some yellow dwarf virus species are primarily vectored by one aphid species whereas others can be transmitted by multiple vectors. Biological diversity within a given vector species (e.g., genotype, biotype) can influence virus transmission efficiency. However, it is unclear what biological factors drive this variation within a given vector species. Understanding how biological variation in vector populations influences virus transmission efficiency can help to identify biological traits that underpin successful transmission in competent vector populations. Here, the available literature on yellow dwarf virus transmission efficiency is synthesized and significant variation in yellow dwarf virus transmission efficiency is detected between different populations for several vector species. Three biological mechanisms that potentially underpin this variation are proposed.