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ABSTRACT: Lettuce mottle virus (LeMoV) and dandelion yellow mosaic virus (DaYMV) infect lettuce in South America and Europe, respectively. LeMoV and DaYMV possess isometric particles, occur at low concentrations in plants and have narrow host ranges. Partial genome sequences of both viruses were obtained using purified viral preparations and universal primers for members of the family Sequiviridae. DaYMV and LeMoV sequences were analyzed and showed identity with other members of the family. Universal primers that detect both viruses and specific primers for LeMoV and DaYMV were designed and used in RT-PCR-based diagnostic assays. These results provide the first molecular data on the LeMoV and DaYMV genomes and suggest that LeMoV is a member of the genus Sequivirus, probably distinct from DaYMV.
Archives of Virology 02/2007; 152(5):999-1007. · 2.11 Impact Factor
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ABSTRACT: LMV-Common and LMV-Most are two seed-borne types of Lettuce mosaic virus (LMV), genus Potyvirus. LMV-Most, but not LMV-Common, overcomes the resistance afforded to lettuce by two recessive genes, mo11 and mo12. An RT-PCR-based assay thought to be specific for LMV-Most also amplified LMV-Tn2, previously typified as LMV-Common. The sequence of selected regions along the genome indicated that LMV-Tn2 is a natural recombinant between LMV-Most and LMV-Common isolates, with a putative recombination site located within the P3 coding region. This is the first evidence of a naturally occurring LMV recombinant isolate.
Archives of Virology 02/2004; 149(1):191-7. · 2.11 Impact Factor
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ABSTRACT: Given their small genome size, the biological cycle of plant viruses is tightly integrated with the cellular processes of their host plants, so that studies of the viral biology will often provide insights into basic cellular processes. In the last decade, two such unforeseen mechanisms were discovered. One concerns intercellular communications: for their movement in infected plants, viruses use channels (plasmodesmata, phloem) also used by the plant to exchange information-rich molecules (proteins, RNAs) between cells. The second phenomenon concerns the existence, in plants, of an anti-viral defence mechanism based on the specific degradation of RNA molecules in the cytoplasm. This same mechanism, also allowing the regulation of gene expression (post-transcriptional gene silencing, PTGS) now appears to be widespread in pluricellular organisms. Besides their general interest, these new results modify drastically our vision of interactions between plant and viruses and raise numerous new research questions.
Comptes Rendus de l Académie des Sciences - Series III - Sciences de la Vie 11/2001; 324(10):935-41.
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ABSTRACT: Full-length infectious cDNA clones were constructed for two isolates (LMV-0 and LMV-E) of Lettuce mosaic virus (LMV), a member of the genus Potyvirus. These two isolates differ in pathogenicity in susceptible and tolerant-resistant lettuce cultivars. In susceptible plants, LMV-0 induces mild mosaic symptoms, whereas LMV-E induces severe stunting, leaf deformation, and a necrotic mosaic. In plants carrying either of the two probably allelic recessive resistance genes mol1 or mol2, LMV-0 is restricted partially to the inoculated leaves. When a systemic invasion does occur, however, symptoms fail to develop. LMV-E overcomes the protection afforded by the resistance genes, resulting in systemic mosaic symptoms. Analysis of the behavior of recombinants constructed between the two virus isolates determined that the HC-Pro protein of LMV-E causes the severe stunting and necrotic mosaic induced by this isolate in susceptible cultivars. In contrast, the ability to overcome mol resistance and induce symptoms in the resistant-tolerant cultivars was mapped to the 3' half of the LMV-E genome. These results indicate that the ability to induce severe symptoms and to overcome the protection afforded by the recessive genes mol1 or mol2 are independent phenomena.
Molecular Plant-Microbe Interactions 07/2001; 14(6):804-10. · 4.43 Impact Factor
