Agropyron mosaic virus Detected in Ohio Wheat (Triticum aestivum)

Abstract

HomePlant DiseaseVol. 102, No. 2Agropyron mosaic virus Detected in Ohio Wheat (Triticum aestivum) PreviousNext DISEASE NOTES OPENOpen Access licenseAgropyron mosaic virus Detected in Ohio Wheat (Triticum aestivum)B. A. Hodge, P. A. Paul, and L. R. StewartB. A. HodgeSearch for more papers by this author, P. A. PaulSearch for more papers by this author, and L. R. Stewart†Corresponding author: L. R. Stewart; E-mail: E-mail Address: [email protected]Search for more papers by this authorAffiliationsAuthors and Affiliations B. A. Hodge P. A. Paul , Department of Plant Pathology, The Ohio State University, Wooster, OH 44691 L. R. Stewart † , USDA-ARS CSWQRU, Wooster, OH 44691. Published Online:30 Nov 2017https://doi.org/10.1094/PDIS-08-17-1223-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Agropyron mosaic virus (AgMV), first described in Ontario in 1937, has since been detected in Wales, Colorado, and Kansas (Catherall et al. 1975; Seifers 1992; Seifers et al. 2008). AgMV is a positive-sense RNA virus in the genus Rymovirus, transmitted by the cereal rust mite Abacarus hystrix (Slykhuis 1969). In an Ohio survey in March to April of 2016, plants with virus-like symptoms, including stunting, chlorosis, and mosaic were collected from both planted soft red winter wheat fields and nearby volunteer wheat at 40 locations across 20 counties. Total RNA extracted from symptomatic plants was pooled by location, subjected to ribosomal RNA depletion, and sequenced using the Illumina HiSeq 2500 platform (100-bp paired-end reads); remaining RNA was used for reverse-transcription polymerase chain reaction (RT-PCR) validation. HiSeq reads were assembled and analyzed with CLC Genomics Workstation 9.1 (CLC Bio, Cambridge, MA) and Sequencher 5.4.6 software (Gene Codes Corp., Ann Arbor, MI). A 9,523 nucleotide consensus sequence, assembled from three >99% identical near-complete virus genomic sequence contigs from three locations (GenBank accession nos. MF621331, MF621332, and MF621333), was 99% identical to the AgMV ND402 isolate (GenBank accession no. AY623626.1). RT-PCR and Sanger sequencing of products using designed primers, AgMV F1 (5′-GCCCAACTCGCATAGGATTA-3′) and AgMV R1 (5′-TTCCTCTGGTGGCTTTATGG-3′), confirmed the AgMV sequence and presence in wheat samples with mosaic symptoms from one location each in Huron, Wayne, and Putnam counties, all of which were associated with nearby volunteer fields. Further testing by RT-PCR detected AgMV in only volunteer wheat in Wayne and Putnam counties and only production wheat in Huron county. AgMV was isolated from Huron and Wayne county samples, which were collected ∼60 miles apart, by rub-inoculation to the soft red winter wheat cultivar Freedom and then subsequent passaging three times. Although no coinfections were observed in the first passage from field tissue, isolates were tested after passaging three times to confirm separation. Plants tested positive for AgMV by RT-PCR and negative for Wheat streak mosaic virus, Brome mosaic virus, Soil-borne wheat mosaic virus, Barley stripe mosaic virus, and Cocksfoot mottle virus. The infected wheat plants showed a light streaking pattern on the youngest leaves approximately 7 to 10 days postinoculation, which then developed into a yellow mosaic on older leaves. Infectivity of Ohio AgMV isolates was tested on a panel of potential host plants. Three replicates composed of three five-plant pots of each tested cultivar were inoculated and scored for AgMV symptoms. For each cultivar, one leaf from each of 12 random plants was pooled and tested for infection by RT-PCR 14 days postinoculation. Confirmed infected plant hosts included 3/3 pools of soft red winter wheat cultivars Hopewell, Truman, Bravo, and Bromfield; Lolium multiflorum (annual ryegrass); and Secale cereale (rye). Infection was not detected in 0/3 tested pools of Avena sativa (oat, cultivar Armour), Hordeum vulgare (barley, cultivar unknown), Zea mays (maize cultivars B73, Oh28, Spirit, Early Sunglow, and Oh1VI), Sorghum bicolor (sorghum, cultivars Atlas and Sart), Sorghum halepense (Johnsongrass), or Dactylis glomerata (orchardgrass). These results agree with a previous report that AgMV infects wheat and rye but not oats (Slykhuis et al. 1966). This is the first detection of AgMV in Ohio and in the Midwest United States. The detection of AgMV at multiple locations in Ohio is significant because of the potential impact it may have on wheat production, and it suggests the need for further monitoring to assess impact in Ohio and nearby states.