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Adaptation of Lettuce mosaic virus to Catharanthus roseus Involves Mutations in the Central Domain of the VPg

May 2014 , Volume 27 , Number  5
Pages  491 - 497

Laurence Svanella-Dumas,1,2 Eric Verdin,3 Chantal Faure,1,2 Sylvie German-Retana,1,2 Patrick Gognalons,3 Jean Luc Danet,1,2 Armelle Marais,1,2 and Thierry Candresse1,2

1UMR 1332 Biologie du Fruit et Pathologie, INRA, CS 20032, 33882 Villenave d'Ornon Cedex, France; 2UMR 1332 Biologie du Fruit et Pathologie, Université de Bordeaux, CS 20032, 33882 Villenave d'Ornon Cedex, France; 3Unité de Pathologie Végétale, INRA, Domaine St Maurice, BP 94, 84143 Montfavet cedex, France

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Accepted 3 January 2014.

An isolate of Lettuce mosaic virus (LMV, a Potyvirus) infecting Madagascar periwinckle (Catharanthus roseus) was identified and characterized by Illumina deep sequencing. LMV-Cr has no close affinities to previously sequenced LMV isolates and represents a novel, divergent LMV clade. Inoculation experiments with other representative LMV isolates showed that they are unable to infect C. roseus, which was not known to be a host for LMV. However, three C. roseus variants of one of these isolates, LMV-AF199, could be selected and partially or completely sequenced. These variants are characterized by the accumulation of mutations affecting the C-terminal part of the cylindrical inclusion (CI) helicase and the central part of the VPg. In particular, a serine to proline mutation at amino acid 143 of the VPg was observed in all three independently selected variants and is also present in the LMV-Cr isolate, making it a prime candidate as a host-range determinant. Other mutations at VPg positions 65 and 144 could also contribute to the ability to infect C. roseus. Inoculation experiments involving a recombinant LMV expressing a permissive lettuce eukaryotic translation initiation factor 4E (eIF4E) suggest that eIF4E does not contribute to the interaction of most LMV isolates with C. roseus.

This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 2014.