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Etiology

Physicochemical Characterization of Maize Mosaic Virus. B. W. Falk, University of Florida, Agricultural Research and Education Center, Belle Glade 33430; J. H. Tsai, University of Florida, Agricultural Research and Education Center, Fort Lauderdale 33314. Phytopathology 73:1536-1539. Accepted for publication 23 May 1983. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-1536.

Virions of maize mosaic virus (MMV) were purified from greenhouse-grown inoculated maize plants and the physicochemical properties of the virions were determined. The best purification procedure was a modified method of those used for sonchus yellow net virus and potato yellow dwarf virus. Electron microscopy of purified preparations showed virions with dimensions of 224 ± 21 x 68 ± 9 nm. Purified preparations injected into Peregrinus maidis, the planthopper vector of MMV, were infectious to maize test plants. MMV had a sedimentation coefficient of 774 as estimated by linear-log sucrose density gradient centrifugation. Analysis of virion proteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed three major virion proteins of relative mass (Mr) 75,000 ± 2,000 (75K), Mr 54,000 ± 3,200 (54K) and Mr 30,000 ± 1,000 (30K). The 75K protein stained for carbohydrate and both the 75K and 30K proteins were solubilized by treatment of virions with nonidet P-40 (NP-40) suggesting that these are G and M proteins, respectively. The 54K protein was not solubilized by NP-40 and is interpreted as an N protein. MMV was also found to have a ss-RNA of ~Mr 4.2 x 10⁶. From these data we conclude that MMV should be placed in the lettuce necrotic yellows virus subgroup of plant rhabdoviruses.