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United States Department of Agriculture

Agricultural Research Service

Title: Host Resistance to Mirafiori Lettuce Big-vein Virus and Virus Sequence Diversity in the Western United States.

Authors
item Wintermantel, William
item Hayes, Ryan

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2006
Publication Date: July 1, 2006
Citation: Wintermantel, W.M., Hayes, R.J. 2006. Host Resistance to Mirafiori Lettuce Big-vein Virus and Virus Sequence Diversity in the Western United States.Phytopathology. 96:S124.

Interpretive Summary: Big vein is an economically damaging disease of lettuce (Lactuca sativa) caused by the Olpidium brassicae vectored Mirafiori lettuce big-vein virus (MLBVV). Although big vein is a perennial problem in the US, the extent of MLBVV infection and diversity was unknown. Lettuce cultivars partially resistant to big vein reduce losses, but do not eliminate disease. While the wild relative, L. virosa, does not develop big vein symptoms, it had not been tested for infection with MLBVV. Lettuce cultivars Great Lakes 65, Pavane, Margarita, and L. virosa accession IVT280 were evaluated for big vein incidence and virus infection in inoculated greenhouse trials. In addition, lettuce samples were collected from field sites in California and Arizona, classified for symptom severity and evaluated for virus infection and isolate diversity by RT-PCR and nucleotide sequencing. Infections with MLBVV were correlated with big vein field symptoms and virus isolates were closely related to those from Europe and Japan. Partial big vein resistance was identified in Margarita and Pavane; however, MLBVV infection was found in asymptomatic plants. Variation for symptom expression and MLBVV accumulation occurred among L. virosa accessions. Accession IVT280 remained symptomless and in most cases virus free, suggesting it is a strong source of resistance.

Technical Abstract: Big vein is an economically damaging disease of lettuce (Lactuca sativa) caused by the Olpidium brassicae vectored Mirafiori lettuce big-vein virus (MLBVV). Although big vein is a perennial problem in the US, the extent of MLBVV infection and diversity was unknown. Lettuce cultivars partially resistant to big vein reduce losses, but do not eliminate disease. While the wild relative, <i>L. virosa</i>, does not develop big vein symptoms, it had not been tested for infection with MLBVV. Lettuce cultivars Great Lakes 65, Pavane, Margarita, and L. virosa accession IVT280 were evaluated for big vein incidence and virus infection in inoculated greenhouse trials. In addition, lettuce samples were collected from field sites in California and Arizona, classified for symptom severity and evaluated for virus infection and isolate diversity by RT-PCR and nucleotide sequencing. Infections with MLBVV were correlated with big vein field symptoms and virus isolates were closely related to those from Europe and Japan. Partial big vein resistance was identified in Margarita and Pavane; however, MLBVV infection was found in asymptomatic plants. Variation for symptom expression and MLBVV accumulation occurred among L. virosa accessions. Accession IVT280 remained symptomless and in most cases virus free, suggesting it is a strong source of resistance.

Last Modified: 10/25/2014
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