VIEW ARTICLE

Electron Microscopy of Soybean Root Nodules Infected with Soybean Mosaic Virus. J. C. Tu, Biological Sciences Electron Microscopy Laboratory, University of Alberta, Edmonton, Alberta, Canada; Phytopathology 63:1011-1017. Accepted for publication 26 February 1973. DOI: 10.1094/Phyto-63-1011.

Thin sections of developing central tissue cells of soybean mosaic virus (SMV)-infected soybean root nodules were studied. The development of rhizobial infection threads and the processes of releasing rhizobia into nodule tissue cells appeared to be little affected by SMV infection. The infection threads of rhizobia were usually present in the young central tissue cells near the meristem of the nodule, and in these cells small SMV aggregates, pinwheels, and bundle inclusions were also found. Cells, free of rhizobial infection threads, were generally infected with SMV. SMV infectivity in root nodules was consistently higher than that in the root tissues. The presence of virus aggregates in the root nodule cells further evidenced that SMV could multiply in the root nodule cells despite the presence of Rhizobium.