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Molecular Plant Pathology

Sour Cherry Strain of Plum Pox Potyvirus (PPV): Molecular and Serological Evidence for a New Subgroup of PPV Strains. L. Nemchinov, National Germplasm Resources Laboratory, Agricultural Research Service, USDA, Building 011A, Room 106, Beltsville, MD 20705; A. Hadidi(2), E. Maiss(3), M. Cambra(4), T. Candresse(5), and V. Damsteegt(6). (2)National Germplasm Resources Laboratory, Agricultural Research Service, USDA, Building 011A, Room 106, Beltsville, MD 20705; (3)Molekulare Phytopathologie, Institut für Pflanzenkrankheiten und Pflanzenschutz, Universität Hannover, Herrenhäuser Strasse 2, D-30419, Hannover, Germany; (4)Departamento de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrárias, Apdo. Oficial, 46113 Moncada, Valencia, Spain; (5)Station de Pathologie Végétale, INRA, Centre de Recherches de Bordeaux, B.P. 81, 33883 Villenave D’Ornon Cedex, France; (6)Foreign Disease-Weed Science Research Unit, ARS, USDA, Frederick, MD 21702. Phytopathology 86:1215-1221. Accepted for publication 25 July 1996. 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, 1996. DOI: 10.1094/Phyto-86-1215.

Properties of the unusual sour cherry strain of plum pox potyvirus (PPV-SoC) were investigated by sequencing its 3’-terminal 1,360 nt and examining its serological reactivity with several monoclonal antibodies (MAbs) to PPV. A significantly low degree of identity of the sequenced region has been found between PPV-SoC and other isolates of PPV. This is due to the high nucleotide divergence between the 5’-terminal region of the coat protein (CP) coding region of PPV-SoC and that of other isolates. Most nucleotide substitutions in the sequenced region are not silent and result in amino acid changes, especially near the N terminus of the CP. The unique 5’ terminus of the PPV-SoC CP coding sequence has been utilized to develop a cRNA probe that hybridizes to PPV-SoC but not to other isolates/members of the D or M subgroups of PPV. The N-terminal region of the PPV-SoC CP contains the recognizable DAG motif that determines aphid transmissibility of potyviruses. Aphid transmission of PPV-SoC to herbaceous and woody hosts has been confirmed experimentally. Serologically reactivity of PPV-SoC with 10 MAbs of PPV suggest that PPV-SoC represents a new serotype of PPV that does not fall into the conventional D or M serotypes/subgroups. We propose that PPV-SoC represents a new subgroup of PPV strains, termed PPV-cherry (PPV-C), and that PPV-SoC is its prototype member.