© 2013 Plant Management Network.
First Report of Soybean vein necrosis-associated virus Affecting Soybeans in Alabama
Kassie Conner, Alabama Cooperative Extension System, Auburn University, AL 36849; Edward J. Sikora and Lee Zhang, Department of Entomology and Plant Pathology, Auburn University, AL 36849; and Charles Burmester, Tennessee Valley Research and Extension Center, Auburn University, Madison, AL 35756
Corresponding author: Kassie Conner. firstname.lastname@example.org
Conner, K., Sikora, E. J., Zhang, L., and Burmester, C. 2013. First report of Soybean vein necrosis-associated virus affecting soybeans in Alabama. Online. Plant Health Progress doi:10.1094/PHP-2013-0729-03-BR.
Soybean plants expressing symptoms typical of Soybean vein necrosis-associated virus (SVNaV, genus Tospovirus) were observed in Limestone Co., Alabama, in early October 2012. The symptoms consisted of brown necrotic tissue along the major veins of the upper and lower leaf surface, resulting in a scorched appearance of damaged leaves (Fig. 1). Symptomatic plants were observed in seven fields in North Alabama consisting of over 1,000 acres of soybeans. All fields showing symptoms were planted with corn prior to soybeans in 2012. Soybean maturity group varied from field to field and ranged from 4.9-6.0. Samples were collected from symptomatic fields and submitted to the Auburn University Plant Diagnostic Laboratory (AU-PDL). Leaves showing symptoms were tested by Polymerase Chain Reaction (PCR) for Tospoviruses at Agdia, Inc. (Elkhart, IN) followed by purification and sequencing. The sample tested weakly positive for the presence of Tospoviruses and had 98% similarity to SVNaV based on sequence identity. Five symptomatic plants were tested for SVNaV at the AU-PDL with polyclonal antibodies using double-antibody sandwich enzyme-linked immunosorbent assay (DAS ELISA) (AC Diagnostics, Inc., Fayetteville, AR). Reverse-transcription PCR (RT-PCR) was carried out using total RNA extracted from all five ELISA-positive plant samples with Qiagen RNeasy kit (Valencia, CA) and specific primers LdetF (5-GAGCCCATAAACCTGTCTGC) and LdetR (5-TGCCATGATGTGCTCAGATT) designed to amplify a 297-bp fragment of the L-RNA (1). An amplicon of the expected size, as determined by agarose gel electrophoresis, was obtained from each sample. Two bands, representing two separate isolates, were excised from the gel, purified using QIAquick gel extraction kit, and sequenced using the Applied Biosystems 3130 genomic analyzer for identification. Sequences from both amplicons shared 99-100% similarity to sequences of SVNaV in GenBank (Accession Nos. GU722317 and HQ728385). Nucleotide sequence data reported are available in GenBank under Accession Nos. KC431808-09. SVNaV is a relatively new disease of soybeans in the United States. It was first reported in Tennessee in 2008 and has since been reported in Arkansas, Kansas, Missouri, Illinois, Mississippi, and Kentucky (1). This is the first report of SVNaV infection associated with soybeans in Alabama. Given the potential impact this virus may have on the soybean industry, its confirmation is a significant step towards developing management recommendations for growers in Alabama.
1. Zhou, J., Kantartzi, S. K., Wen, R. H., Newman, M., Hajimorad, M. R., Rupe, J. C., and Tzanetakis, I. E. 2011. Molecular characterization of a new tospovirus infecting soybean. Virus Genes 43:289-295.