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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #236854
Title: Spinach: A new natural host of Impatiens necrotic spot virus in California.

Author
item Liu, Hsing Yeh
item Sears, John
item Mou, Beiquan

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2009
Publication Date: 6/2/2009
Citation: Liu, H., Sears, J.L., Mou, B. 2009. Spinach: A new natural host of Impatiens necrotic spot virus in California.. Plant Disease 93:673, 2009

Interpretive Summary: Impatiens necrotic spot virus (INSV) was detected in a spinach (Spinacia oleracea) experimental field in Monterey County, CA in October of 2008. Spinach plants exhibiting severe stunting and with leaves that showed interveinal yellowing, thickening, and deformation were observed on cvs. Tigercat (19.8%), Lazio (39.3%), and Bordeaux (33.7%). Symptomatic plants were positive for INSV and were negative for Tomato spotted wilt virus, Cucumber mosaic virus, and Tobacco mosaic virus with immunostrips (Agdia, Elkgart, IN). The INSV-positive spinach was used for mechnical inoculations and was successfully transmitted to Nicotiana benthamiana, Chenopodium quinoa, and spinach. All infected plants were positive for INSV with immunostrips. To further confirm the presence of INSV, reverse transcription (RT)-PCR analysis was conducted. Total RNA was extracted from the symptomatic spinach plants and used as a template in RT-PCR using primers specific to the INSV coat protein gene (GenBank Accession No. DQ425096). Amplicons of the expected size (approximately 364 bp) were obtained from both field-infected and mechanically inoculated spinach plants. Four amplicons were sequenced and compared with INSV coat protein sequence in GenBank to confirm the identity of the products, which had 99% nucleotide identity with GenBank Accession Nos. L20885, DQ523597, DQ523598, X66872, L20886, D00914, AB109100, and DQ425096. INSV can be one of the most serious viral pathogens of ornamental plants in North America and Europe. Recently, INSV is emerging as a pathogen of vegetable crops infecting peppers, potatoes, peanut, and most recently on lettuce. To our knowledge, this is the first report of natural occurrence of INSV on spinach plants in California.

Technical Abstract: Impatiens necrotic spot tospovirus (INSV; family Bunyaviridae) was detected in a spinach (Spinacia oleracea) experimental field in Monterey County, CA in October of 2008. Spinach plants exhibiting severe stunting and with leaves that showed interveinal yellowing, thickening, and deformation were observed on cvs. Tigercat (19.8%), Lazio (39.3%), and Bordeaux (33.7%). Symptomatic plants were positive for INSV and were negative for Tomato spotted wilt virus, Cucumber mosaic virus, and Tobacco mosaic virus with immunostrips (Agdia, Elkgart, IN). The INSV-positive spinach was used for mechnical inoculations and was successfully transmitted to Nicotiana benthamiana, Chenopodium quinoa, and spinach. All infected plants were positive for INSV with immunostrips. To further confirm the presence of INSV, reverse transcription (RT)-PCR analysis was conducted. Total RNA was extracted from the symptomatic spinach plants with RNeasy Plant Kit (Qiagen Inc., Valencia, CA) and used as a template in RT-PCR using novel forward (5’-GGATGTAAGCCCTTCTTTGTAGTGG-3’) and reverse (5’-CCTTCCAAGTCACCCTCTGATTG-3’) primers specific to the INSV coat protein gene (GenBank Accession No. DQ425096). Amplicons of the expected size (approximately 364 bp) were obtained from both field-infected and mechanically inoculated spinach plants. Four amplicons were sequenced and compared with INSV coat protein sequence in GenBank to confirm the identity of the products, which had 99% nucleotide identity with GenBank Accession Nos. L20885, DQ523597, DQ523598, X66872, L20886, D00914, AB109100, and DQ425096. INSV can be one of the most serious viral