VIEW ARTICLE

Identification of an Ash Strain of Tobacco Ringspot Virus. C. R. Hibben, Kitchawan Research Laboratory of the Brooklyn Botanic Garden, Ossining, New York 10562; R. F. Bozarth, Boyce Thompson Institute for Plant Research, Inc., Yonkers, New York 10701. Phytopathology 62:1023-1029. Accepted for publication 22 March 1972. DOI: 10.1094/Phyto-62-1023.

Host range tests with a virus isolated from leaves of declining Fraxinus americana revealed local and systemic symptoms similar to those caused by ringspot viruses. Properties in crude sap of infected Vigna sinensis indicated similarities between the ash isolate and tobacco ringspot virus (TRSV). Three components were separated after sucrose density-gradient centrifugation of the purified virus. The sedimentation velocities of the top, middle, and bottom components were 58, 101, and 127 S, respectively. Infectivity was associated only with the bottom component, and was not enhanced by mixtures with the middle component. Electron micrographs of the bottom component showed isometric particles ca. 26 nm in diam. The purified ash virus reacted positively with TRSV antisera in Ouchterlony agar double-diffusion tests. In reciprocal tests, antisera to the ash virus reacted positively with homologous antigen and TRSV. From these results, the virus isolated from ash was identified as a strain of TRSV.