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Vector Relations

Protein Coats of Two Strains of Cucumber Mosaic Virus Affect Transmission by Aphis gossypii. Abdullah Gera, Virus Laboratory, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel; G. Loebenstein(2), and B. Raccah(3). (2)(3)Virus Laboratory, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. Phytopathology 69:396-399. Accepted for publication 31 August 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-396.

Two strains of cucumber mosaic virus (CMV) were studied to determine reasons for differences in transmission efficiency by Aphis gossypii. Strain CMV-T, which is highly transmissible from tobacco to cucumber (90%) and CMV-6 a poorly transmitted one (10%) were used. Difference in transmission was independent of host plant and not correlated with concentration of virus in the leaf. There were no indications of a helper factor associated with CMV-T or of an inhibitor that decreased transmission of CMV-6. Purified CMV-6 at high concentrations was acquired through a parafilm membrane almost as efficiently as was purified CMV-T and subsequently was transmitted by aphids to test plants. However, reducing virus concentration decreased transmission of CMV-6 markedly, whereas that of CMV-T was decreased considerably less. Differences in RNA profiles were observed after electrophoresis in acrylamide gels. Exchanging CMV-6 coat protein with CMV-T coat in vitro, increased aphid transmission rates markedly whereas replacing CMV-T coat by CMV-6 protein decreased transmission. These results were supported by enzyme-linked immunosorbent assay of single aphids. Apparently, the coat protein determines transmissibility of CMV strains by aphids.