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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #181937
Title: HOST RESISTANCE TO MIRAFIORI LETTUCE BIG-VEIN VIRUS AND LETTUCE BIG-VEIN ASSOCIATED VIRUS AND VIRUS SEQUENCE DIVERSITY AND FREQUENCY IN CALIFORNIA

Author
item Hayes, Ryan
item Wintermantel, William - Bill
item Nicely, Patricia
item RYDER, EDWARD - USDA-COLLABORATOR

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2005
Publication Date: 2/3/2006
Citation: Hayes, R.J., Wintermantel, W.M., Nicely, P.A., Ryder, E.J. Host resistance to Mirafiori lettuce big-vein virus and Lettuce big-vein associated virus and virus sequence diversity and frequency in California. Plant Disease 90:233-239. 2006.

Interpretive Summary: Big vein (BV) is an economically damaging disease of lettuce (Lactuca sativa L.) caused Mirafiori lettuce big-vein virus (MLBVV) and spread between plants by the soil borne fungus Olpidium brassicae. Lettuce big-vein associated virus (LBVaV) is additional virus commonly found in symptomatic plants, but no causative relationship has been demonstrated. Although BV is a perennial problem in the US, the extent of MLBVV and LBVaV infection and DNA sequence diversity in California is unknown. Partially resistant lettuce cultivars that have low percentages of symptomatic plants can reduce disease damage, but do not eliminate the problem. L. virosa L. is a wild relative of lettuce that does not develop BV symptoms, but has not previously been tested for infection of MLBVV or LBVaV. Lettuce cultivars Great Lakes 65, Pavane, Margarita, and L. virosa accession IVT280 were evaluated for BV disease resistance and virus infection in inoculated greenhouse trials and from field sites in California, and classified for symptom severity. Reverse transcription-polymerase chain reaction and DNA sequencing were used to determine whether plants were infected with MLBVV and LBVaV, and genetic diversity among viral isolates, respectively. Infections with MLBVV and MLBVV/LBVaV were confirmed in US production areas and viral isolates were closely related to those found in Europe and Japan. Margarita and Pavane were determined to be partially resistant to BV; however, MLBVV infection was found in asymptomatic plants. L. virosa IVT280 remained symptomless and virus free, suggesting it is a source of apparent immunity to MLBVV and LBVaV.

Technical Abstract: Big vein (BV) is an economically damaging disease of lettuce (Lactuca sativa L.) caused by the Olpidium brassicae vectored Mirafiori lettuce big-vein virus (MLBVV). Lettuce big-vein associated virus (LBVaV) is also frequently identified in symptomatic plants, but no causative relationship has been demonstrated. Although BV is a perennial problem in the US, the extent of MLBVV and LBVaV infection and diversity is unknown. Partially resistant lettuce cultivars reduce losses, but do not eliminate disease. L. virosa L. does not develop BV symptoms, but has not previously been tested for accumulation of MLBVV or LBVaV. Lettuce cultivars Great Lakes 65, Pavane, Margarita, and L. virosa accession IVT280 were evaluated for BV incidence and virus infection in inoculated greenhouse trials and from field sites in California, and classified for symptom severity. Reverse transcription-polymerase chain reaction and DNA sequencing were used to determine infection with MLBVV and LBVaV, and genetic diversity among viral isolates, respectively. Infections with MLBVV and MLBVV/LBVaV were confirmed in US production areas and isolates were closely related to those found in Europe and Japan. Partial BV resistance was identified in Margarita and Pavane; however, MLBVV infection was found in asymptomatic plants. L. virosa IVT280 remained symptomless and virus free, suggesting it is a promising source of immunity.