VIEW ARTICLE

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.