VIEW ARTICLE

Etiology

Isolation and Comparison of Two Strains of Soybean Mosaic Virus. P. L. Hunst, Graduate assistant, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061; S. A. Tolin, associate professor, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061. Phytopathology 72:710-713. Accepted for publication 14 October 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-710.

Two isolates of soybean mosaic virus (SMV) were collected in Virginia and characterized. One isolate, SMV-VA, was similar to a type strain and was classified into the G1 strain group on soybean differential cultivars. It infected only soybean cultivars known to be susceptible to SMV, and also infected cowpea and Alaska pea systemically, and Topcrop bean locally. The second isolate, SMV-OCM, induced mild symptoms on SMV-susceptible soybeans but caused severe systemic necrosis on SMV-resistant Marshall and Ogden soybeans, reactions typical of strains in the G3 strain group. It failed to induce necrotic lesions on Topcrop bean and to infect pea. The two strains reacted serologically with SMV-VA antiserum and to other known SMV antisera. SMV-VA induced typical scroll-type pinwheels in the cytoplasm of infected cells. Similar pinwheels were induced by SMV-OCM and were always associated with extensive cytoplasmic strands that extended into the vacuoles and contained virus particles.