Bdv2 resistance gene against barley yellow dwarf disease in wheat

Barley/Cereal yellow dwarf viruses (B/CYDV), responsible of one of the most important diseases on cereals, is a complex of at least ten virus species. The most widespread and abundant species of B/CYDV in France is Luteovirus pavhordei (former Barley yellow dwarf virus (BYDV-PAV), genus Luteovirus, family Tombusviridae). BYDV-PAV is mainly transmitted by the bird cherry-oat aphid Rhopalosiphum padi in a persistent, circulative and non-propagative manner. For the last three decades, the main method for the management of B/CYDV in cereals was based on the use of insecticide treatments (coated seeds and/or foliar sprays). However, the recent ban on neonicotinoids in the EU and the emergence of pyrethroid-resistant aphids have sped up the development of cultivars with a phenotype resistant against virus and/or vector as an alternative to insecticides. Bdv2 is one of the four B/CYDV resistance genes that has been introduced into wheat germplasm. The first wheat cultivar carrying Bdv2 (i.e. cv. Tweeteo [RAGT]) has recently been made available to French growers. However, it has previously been shown that the pressure induced by Bdv2 gene could lead to the selection of more virulent isolate(s) capable of overcoming the resistance phenotype. To avoid a rapid breakdown of Bdv2in fields, it is important to study i) mechanisms behind the Bdv2 resistance and ii) links between Bdv2 and the genetic background of wheat genotypes.