2010). Virus-like particles observed in plants with gentian tumorous symptoms. Jpn. J. Phytopathol. 76: 21-24. Gentian tumorous symptoms have been known in Nagano, Iwate and other prefectures since 1985. Previously undescribed virus-like particles were found in gentian (Gentiana spp.) plants collected in Iwate Prefecture that had galls or tumors on stems and roots. In transmission electron micrographs of ultrathin sections of tissue from symptomatic plants, virus-like isometric particles about

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... 0 nm in diameter, which had dense cores about 40 nm in diameter with less dense outer shells, were scattered or aggregated in small masses in the cytoplasm of phloem parenchyma cells and in the sieve tubes of galls or tumors. Virus-like particles were observed in stems, crowns and roots but not in leaves and petals. Similar particles were detected by negative staining using uranyl acetate or phosphotungstic acid (pH 7.0) in homogenates of roots fixed with glutaraldehyde.