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Etiology

Serological Distinction of Watermelon Mosaic Virus Isolates. D. E. Purcifull, Department of Plant Pathology, University of Florida, Gainesville, FL 32611; E. Hiebert, Department of Plant Pathology, University of Florida, Gainesville, FL 32611. Phytopathology 69:112-116. Accepted for publication 18 August 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-112.

Antisera to purified preparations of Florida isolates of WMV type 1 (WMV-1 FL) and WMV type 2 (WMV-2 FL) were used in immunodiffusion tests with sodium dodecyl sulfate (SDS)-treated extracts from virus infected plants. Based on reciprocal tests with sera collected 2–6 mo after the first injection, WMV-1 FL and WMV-2 FL did not cross react. Among 13 other WMV isolates obtained from other areas, three types were identified: (i) isolates that were closely related to WMV-1 FL but not reactive with WMV-2 FL, viz, one isolate each from California, New York, Texas, Australia, Jordan, and Greece; (ii) isolates that were closely related to WMV-2 FL but not reactive with WMV-1 FL, viz, a single isolate each from Arizona, New York, Australia, and New Zealand and two from California; and (iii) an isolate from Morocco, which was nonreactive with either WMV-1 FL or WMV-2 FL. The SDS-immunodiffusion methods were reliable for detecting either WMV-1 or WMV-2 in extracts from symptomatic leaves from a variety of host plants. Freeze-dried leaf extracts proved convenient as reference antigens. The papaya ringspot virus was closely related serologically to WMV-1 FL but nonreactive with WMV-2 FL, whereas soybean mosaic virus was unrelated to WMV-1 FL and related to, but distinct from, WMV-2 FL.