Claudio Ratti

First report of barley yellow mosaic virus in barley in Spain.

Recently, the presence of Barley mild mosaic virus (BaMMV) and the weakly serological detection of Barley yellow mosaic virus (BaYMV) were reported in Spain (1); both viruses are members of the genus Bymovirus (family Potyviridae). Random and symptomatic surveys were conducted during February and March of 2003 in barley fields in northeastern Spain to determine the occurrence of BaMMV and BaYMV. Leaves from 316 samples collected in 15 fields were analyzed using enzyme-linked immunosorbent assay (ELISA) with commercial antisera specific for BaYMV and BaMMV (Loewe Biochemica, Munich) as well as antisera against both viruses (provided by T. Klumen). Positive ELISA samples were further analyzed using reverse transcription-polymerase chain reaction (RT-PCR) with specific primers that amplify 445 bp of BaMMV and 433 bp of BaYMV (2). Complete agreement was observed between the ELISA and RT-PCR results. Mixed infections of BaYMV and BaMMV were detected in 10 samples, BaYMV in 5 samples and BaMMV in 3 samples. Samples positive for both viruses that exhibited clear mosaic symptoms were collected in two fields. RT-PCR products from five BaYMV-infected samples were cloned and sequenced and showed 96 to 98% identity to BaYMV isolates previously reported from Europe (Genbank Accession Nos. AJ1515479-85 and X95695-7) and 92 to 95% identity with isolates reported from Asia (GenBank Accession Nos. AB023585-96, AJ132268, AJ224619-22, AJ224624-28, AF536944-46, AF536948-58, D01091, D00544, and Z24677). Sequence identity of Spanish isolates were 96 to 99%. To our knowledge, this is the first report of BaYMV infecting barley in Spain and illustrates the association of both Bymoviruses infecting barley. References: (1) M. A. Achon et al. Plant Dis. 87:1004, 2003. (2) D. Hariri et al. Eur. J. Plant Pathol. 106:365, 2000.