S.06. Biological and molecular diversities of Barley yellow dwarf virus infection in the presence/absence of resistance gene Yd2 in barley cultivars and breeding lines
Abstract
Barley yellow dwarf virus (BYDV) is a member of genus Luteovirus family Luteoviriodae. BYDV is a causal agent of cereal disease like yellowing, stunting and dwarfing and distributed worldwide. The virus is transmitted by more than 24 species of aphids by persistent manner. BYDV is divided into several serotypes based on vector specificity. BYDV-PAV strain, transmitted by Rhopalosiphum padi and Sitobion avenue, occurs most frequently in the Czech Republic. Natural resistance of BYDV-PAV is limited, only a few genes associated with certain level of resistance have been identified. The best characterized resistance (or tolerance) genes are Yd2 in barley and Bdv1 and Bdv2 in wheat, which confer a certain level of resistance to BYDV-PAV. In this report we have evaluated resistance status and genetic variability of BYDV-PAV in different barley cultivars and breeding lines harbouring Yd2 gene. When testing different cultivars and breeding lines for several years, it was found thatYd2 gene can promote high level of protection against BYDV-PAV in barley. Only mild symptoms often occurred and significantly lower reductions of plant height and grain yield were usually detected. However, the mechanism of Yd2 based protection is so far unknown. We have performed a genetic analysis of BYDV-PAV based on coat protein (CP) gene to verify if the presence or absence of Yd2 gene in barley has any impact on emergence of CP gene variation. A one-step-RT-PCR has developed targeting complete CP gene of BYDV-PAV. The CP amplicons of BYDV-PAV derived from different barley lines were directly sequenced. The BYDV-PAV CP sequence has been analyzed (both nucleotide and amino acid level) and the results will be presented.
