VIEW ARTICLE

Etiology

Virions and Ultrastructural Changes Associated with Blueberry Red Ringspot Disease. K. S. Kim, Department of Plant Pathology, University of Arkansas, Fayetteville 72701; D. C. Ramsdell(2), J. M. Gillett(3), and J. P. Fulton(4). (2)(3)Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824; (4)Department of Plant Pathology, University of Arkansas, Fayetteville 72701. Phytopathology 71:673-678. Accepted for publication 5 November 1980. Copyright The American Phytopathological Society. DOI: 10.1094/Phyto-71-673.

An ultrastructural study of red ringspot-diseased specimens of highbush blueberry (Vaccinium corymbosum L.) revealed viruslike particles (VLPs) in both cytoplasm and nuclei of leaf cells. In the cytoplasm, the particles were embedded in circular inclusions composed of an electron-dense matrix with electron-lucent areas and surrounded by rough endoplasmic reticulum. In the nucleus, particles were associated with the nucleolus or lipid globules. Purified preparations from diseased blueberry leaves revealed large spherical VLPs 42–46 nm in diameter. Density gradient centrifugation of purified preparations in either sucrose or cesium chloride gradients always resulted in two absorbance peaks. Infectivity of purified preparations could not be demonstrated. Although the ultrastructural studies showed similarities to caulimoviruses, no serological reaction could be demonstrated with cauliflower mosaic virus antiserum.