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Etiology

Identification, Partial Sequencing, and Detection of a Potyvirus from Kalanchoë blossfeldiana. K. Husted, biotechnology group, Department of Plant Pathology, Danish Institute of Plant and Soil Science, Research Centre for Plant Protection, Lottenborgvej 2, DK-2800 Lyngby; K. Bech(2), M. Albrechtsen(3), and B. Borkhardt(4). (2)Department of Plant Pathology, Danish Institute of Plant and Soil Science, Research Centre for Plant Protection, Lottenborgvej 2, DK-2800 Lyngby; (3)(4)biotechnology group, Department of Plant Pathology, Danish Institute of Plant and Soil Science, Research Centre for Plant Protection, Lottenborgvej 2, DK-2800 Lyngby. Phytopathology 84:161-166. Accepted for publication 9 October 1993. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/Phyto-84-161.

Flexuous, filamentous virus particles with an average length of 724 nm and showing a characteristic green island mosaic pattern were observed in Kalanchoë blossfeldiana. The virus was sap inoculated from naturally infected K. blossfeldiana plants to Chenopodium quinoa and purified from these plants. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the capsid protein size was estimated to be 33 kDa. Of 14 plant species inoculated, only C. quinoa and C. amaranticolor showed local symptoms. Immunosorbent electron microscopy showed the virus to be serologically unrelated to 10 other potyviruses. The virus was aphid transmitted. This ability was lost, however, after serial mechanical transmissions. The intact virions were used for antiserum preparation, and RNA was purified from virions for cDNA cloning and sequencing. A database search showed the virus to be closely related to but distinct from turnip mosaic potyvirus. On the basis of these investigations, it is concluded that the virus is a hitherto undescribed potyvirus, and the name Kalanchoë mosaic potyvirus is suggested. The prepared antiserum was very specific and sensitive in enzyme-linked immunosorbent assays, and this method is recommended for routine testing.