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Assay for Viruses and Mycoplasmas Using Serologically Specific Electron Microscopy. K. S. Derrick, Associate Professor, Department of Plant Pathology, Louisiana State University, Baton Rouge 70803; R. H. Brlansky, Graduate Assistant, Department of Plant Pathology, Louisiana State University, Baton Rouge 70803. Phytopathology 66:815-820. Accepted for publication 23 December 1975. DOI: 10.1094/Phyto-66-815.

Serologically specific electron microscopy (SSEM) was further developed as a diagnostic technique for plant viruses. The technique was shown to apply to a variety of plant viruses and to the corn stunt mycoplasma (CSM). Assays of barley yellow dwarf virus in crude extracts were easily done using a mouse antiserum produced with a partially purified virus preparation. The addition of sucrose (to 0.4 M) to virus extracts and washing buffers greatly reduced the amount of debris on SSEM grids. The dilution of antiserum used to prepare SSEM grids did not have a significant effect on the number of virus particles attached, except at extremely high antiserum dilutions. In assays of young cultures of CSM and CSM-infected corn, filamentous forms were specifically attached to SSEM grids; in assays of older cultures only spherical forms, 0.1-0.2 µm in diameter, were observed.