A preliminary survey to identify virus diseases affecting wheat in Uzbekistan was conducted during May 2001. The survey covered 12 wheat fields from 2 cereal-growing regions (Tashkent-Angren and Tashkent-Samarkand). A total of 250 wheat samples with symptoms suggestive of virus infection were collected and tested for the presence of nine viruses by tissue-blot immunoassay (TBIA) (1) at the Virology Laboratory of ICARDA, Aleppo, Syria, using the following antisera: monoclonal antibodies for Cereal yellow dwarf virus-RPV (CYDV-RPV) (ATCC PVAS-669 [American Type Culture Collection, Manassas, VA]) and Barley yellow dwarf virus-MAV (BYDV-MAV) (ATCC PVAS-673); and polyclonal antibodies for BYDV-SGV and BYDV-RMV (3); BYDV-PAV, Barley stripe mosaic virus, and Wheat streak mosaic virus (from Virology Laboratory, ICARDA); Wheat dwarf virus (provided by J. Vacke, Research Institute of Crop Production, Prague, Czeck Republic); and Barley yellow striate mosaic virus (BYSMV) isolated from Lebanon (2). The most common virus present was BYDV-PAV (detected in 12% of the 250 samples tested), followed by BYDV-SGV (10.8%), BYSMV (5.6%), BYDV-RMV (2.4%), BYDV-MAV (2%), and CYDV-RPV (1.2%). CYDV-RPV was detected in three fields; one field was 50 km southeast of Tashkent, and the other two fields were between Tashkent and Samarkand. The majority of BYSMV-positive samples originated from the same field, ≈40 km northeast of Samarkand. Field symptoms of BYSMV-infected plants included yellow flag leaf and stunting. All samples that produced a positive reaction to BYSMV-Lebanon antiserum were tested against four other rhabdovirus antisera: BYSMV-Italy, BYSMV-Morocco, Cereal chlorotic mottle virus, and American wheat striate mosaic virus. Serological tests showed that 100% of the samples reacted strongly with BYSMV-Italy and BYSMV-Morocco. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by western blots, extracts from BYSMV-infected plants were found to contain 66- and 47-kDa structural proteins, typical of G and N proteins of rhabdoviruses, both of which reacted strongly with BYSMV-Italy antiserum. To our knowledge, this is the first report of BYSMV and CYDV-RPV in Uzbekistan.
References: (1) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994. (2) K. M. Makkouk et al. Plant Dis. 85:446, 2001. (3) G. N. Webby and R. M. Lister. Plant Dis. 76:1125, 1992.