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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #248825
Title: First report of Beet necrotic yellow vein virus infecting spinach in California.

Author
item Liu, Hsing Yeh
item Mou, Beiquan
item Richardson, Kelley
item KOIKE, STEVE - University Of California - Cooperative Extension Service

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2010
Publication Date: 5/1/2010
Citation: Liu, H., Mou, B., Richardson, K.L., Koike, S.T. 2010. First report of Beet necrotic yellow vein virus infecting spinach in California. Plant Disease. 94:640.

Interpretive Summary: Rhizomania is one of the most devastating diseases of sugarbeet. This disease is caused by Beet necrotic yellow vein virus (BNYVV). In 2009, plants from two spinach (Spinacia oleracea) experimental fields in Monterey County and one commercial spinach field in Ventura County of California exhibited vein clearing, mottling, interveinal yellowing and stunting symptoms. For experimental fields, up to 44% of spinach plants were infected. Using a transmission electron microscope, rigid rod-shaped particles were observed from plant sap of the symptomatic spinach. Analysis using a DAS-ELISA assay for BNYVV showed that the symptomatic plants were positive. Symptomatic spinach from both counties was used for mechanical transmission experiments. Chenopodium quinoa, Tetragonia expensa, and sugar beet (Beta vulgaris) showed chlorotic local lesions, B. macrocarpa and spinach showed systemic infections. To further confirm the presence of BNYVV, reverse transcription-PCR (RT-PCR) was conducted. Total RNA was extracted from the field and mechanically inoculated symptomatic spinach plants and used as a template in RT-PCR. Forward and reverse primers specific to the BNYVV RNA-3 P25 protein gene from the beet isolate were used. Four RT-PCR products were sequenced (GenBank Accession No. GU135626) and compared with BNYVV sequences in GenBank. Sequences from the spinach plants had 99 % nucleotide and 94-100% amino acid identity with BNYVV RNA-3 P25 protein sequences available in the GenBank. Based on data from electron microscopy, serology and molecular analyses, the virus was identified as BNYVV. BNYVV has been reported from spinach fields in Itay. To our knowledge, this is the first report of BNYVV occurring naturally on spinach in California. BNYVV is transmitted by the zoospores of the soil-inhabiting plasmodiophorid Polymyxa betae. BNYVV could be a new threat to spinach production in the state.

Technical Abstract: In 2009, plants from two spinach (Spinacia oleracea) experimental fields in Monterey County and one commercial spinach field in Ventura County of California exhibited vein clearing, mottling, interveinal yellowing and stunting symptoms. For experimental fields, up to 44% of spinach plants were infected. Using a transmission electron microscope, rigid rod-shaped particles with central canals were observed from plant sap of the symptomatic spinach. Analysis using a DAS-ELISA assay for Beet necrotic yellow vein virus (BNYVV) showed that the symptomatic plants were positive. Symptomatic spinach from both counties was used for mechanical transmission experiments. Chenopodium quinoa, Tetragonia expensa, and sugar beet (Beta vulgaris) showed chlorotic local lesions, B. macrocarpa and spinach showed systemic infections. To further confirm the presence of BNYVV, reverse transcription-PCR (RT-PCR) was conducted. Total RNA was extracted from the field and mechanically inoculated symptomatic spinach plants using RNeasy Plant Kit (Qiagen Inc., Valencia, CA) and used as a template in RT-PCR. Forward and reverse primers specific to the BNYVV RNA-3 P25 protein gene from the beet isolate were used. Amplicons of the expected size (approximately 860 bp) were obtained. Four RT-PCR products were sequenced (GenBank Accession No. GU135626) and compared with BNYVV sequences in GenBank. Sequences from the spinach plants had 99 % nucleotide and 94-100% amino acid identity with BNYVV RNA-3 P25 protein sequences available in the GenBank. Based on data from electron microscopy, serology and molecular analyses, the virus was identified as BNYVV. BNYVV has been reported from spinach fields in Itay. To our knowledge, this is the first report of BNYVV occurring naturally on spinach in California. BNYVV is transmitted by the zoospores of the soil-inhabiting plasmodiophorid Polymyxa betae. BNYVV could be a new threat to spinach production in the state.