July 15, 2003
Source: American Phytopathological Society, DISEASE NOTES [edited]

Occurrence of Barley mild mosaic virus on barley in Spain
M. A. Achon, Area de Proteccio de Conreus, Centre UdL-IRTA Rovira Roure 191, 25198 Lleida, Spain; and C. Ratti and C. Rubies-Autonell, DiSTA, Via Filippo Re 8, 40126-Bologna, Italy. Plant Dis. 87:1004, 2003; published on-line as D-2003-0604-01N, 2003. Accepted for publication 16 May 2003.

Mosaic and yellowing symptoms were observed on winter barley during March of 2002 in northeastern Spain. Symptoms were similar to those caused by Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV), members of the genus Bymovirus (family Potyviridae).

Leaves from 17 samples of barley were analyzed by enzyme-linked immunosorbent assay (ELISA) using antisera specific for BaYMV (Bio-Rad Laboratories, Hercules, CA) and BaMMV (Loewe Biochemica, Munich).

5 samples tested positive with the BaYMV antiserum, and 2 samples were positive with the BaYMV and BaMMV antisera. Ranges of ELISA values were from 3.8 to 13 times higher than the negative controls with the BaYMV antiserum and from 18 to 21 times higher with the BaMMV antiserum.

Mixed infections were further analyzed by reverse transcription-polymerase chain reaction (RT-PCR) using specific primers that amplify 433 bp of BaYMV (1) and 445 bp of BaMMV coat protein gene (primer 1:5'GCG 7CCGTT GCA ACT GA 3' and primer 2: 5'GAA TTGCTT GTG CCA ACA 3'. A PCR product of the expected size was observed with BaMMV primers but not with BaYMV primers.

The sequence of BaMMV PCR product was determined and compared with that of the equivalent regions of other BaMMV isolates (Genbank Accession Nos. AJ242725, AJ224872, D83410, D83408, L49381, Y10973, and Y10974). The greatest nucleotide identity (96-98 percent) was found with isolates from
Germany and Italy, followed by those from France and the United Kingdom (89 percent), and the lowest identity being with isolates from Asia (85-88 percent).

The BaYMV presence needs to be confirmed. To our knowledge, this is the first report of a bymovirus infecting barley in Spain, and illustrates the continuing spread within Europe of viruses vectored by _Polymyxa graminis_ Led.

Reference: (1) D. Hariri et al. Eur. J. Plant Pathol. 106:365, 2000.

[This is the first report of BaYMV and BaMMV in ProMED-mail. BaYMV was first reported in barley (_Hordeum vulgare_) in Japan in 1940. It is transmitted by the soil-inhabiting fungus _Polymyxa graminis_ and is also mechanically transmissible. It spreads in Belgium, France, Germany, Italy, Japan, the Netherlands, and the UK. BaMMV, reported from Germany in 1984, is also transmitted by _P. graminis_ and shares transmission properties similar to those of BaYMV. It is present in eastern Asia and Eurasia as well as Belgium, China, France, Germany, Greece, Japan, and the UK. BaMMV resistance genes (rmm) are different from those for BaYMV (rym), as would be expected. - Mod.DH]