|HILL, JOHN - Iowa State University|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/27/2014
Publication Date: 11/1/2014
Citation: Martin, K.M., Hill, J.H., Cannon, S.B. 2014. Occurrence and characterization of Bean common mosaic virus strain NL1 in Iowa. Plant Disease. 98(11):1593. DOI: 10.1094/PDIS-07-14-0673-PDN.
Interpretive Summary: Viruses present in Iowa cause crop loss every year, primarily in legume hosts such as common bean (Phaseolus vulgaris) and soybean (Glycine max). To determine which viruses are present in central Iowa, we conducted a survey of legumes in Story county. Bean common mosaic virus NL1 was found and a number of plants were inoculated to determine if they were hosts to this virus and strain. We identified fourteen cultivars of common bean that are susceptible to this virus and nine that were resistant. The tested soybean variety was also resistant. This study informs farmers of which varieties of common bean should be avoided to prevent the spread of this virus.
Technical Abstract: Bean common mosaic virus (BCMV) and the related Bean common mosaic necrosis virus (BCMNV) are widely distributed across the United States infecting primarily common bean (Phaseolus vulgaris). Eight characterized pathotypes have been distinguished on host differential cultivars. To further characterize potyviruses in central Iowa, a survey of legumes was conducted in Story County. Of the legumes tested, leaves of Phaseolus vulgaris cvs Taos Red and Colorado Bolitas had a mosaic pattern present on larger mature leaves. These leaves were sent to Agdia Inc. for screening and tested positive for the potyvirus group test. Reverse transcription PCR was conducted with total RNA (Qiagen RNA extraction kit) from the symptomatic leaves. A fragment of virus was amplified using degenerate primers, forward: 5’ TGYGTNGAYGAYYTYAAYAA 3’  and reverse: 5’ TCRTARAARTCRAAIGCRTAICKIG 3’  amplifying a ~ 1kb fragment. The closest Genbank BLAST hits were BCMV strain NL1 (AY112735) and BCMV MS1 (EU761198), both at 97% identity. Sequencing from positions 38-10037nts showed a 99% similarity to BCMV-NL1 (AY112735), and 98% similarity to BCMV MS1 (EU761198). Host plant symptoms include vein-banding mosaic, stunting, leaf curl and rugosity. Severity is dependent on the cultivar. Symptomatic hosts (upon rub inoculation) included Phaseolus vulgaris cvs. Starlight, Tohono O’odham vaya Amarillo, Black Valentine Stringless, Sutter Pink, Hidatsa red, Stringless Green Refugee, Burpees Stringless Improved Bush, Princess d’Artois, and Princess Double de Holland. Asymptomatic hosts included Phaseolus vulgaris cvs. Sierra, Sierra Differential, Great Northern Tara, Tara, Dubelle Witte and Vigna radiata. Non-host plants included Phaseolus vulgaris cvs. Widusa, Othello, Sacramento, Red Kidney, Provider, Black Turtle Soup, Victor, Rogers stringless green refugee and Witte boon, as well as, Glycine max cv Williams, Cucumis sativus cv. Straight 8, Solanum lycopericum cvs. Reine des Hatives and Hardin’s miniature tomato, Vicia faba, Pisum sativum var. macrocarpon, Vigna unguiculata, Vigna unguiculata subsp. sesquipedalis, and Apios americana were also not hosts to this virus. To our knowledge, this is the first report to identify a specific strain of BCMV in the Midwest United States. Considering the high acreage of beans planted in neighboring states, Minnesota and Michigan, susceptible bean varieties reported here should be avoided to prevent spread.