Abstract
The spherical virus-like particles, 35nm in diameter, were isolated from the rice plants infected with rice ragged stunt, dwarf, black-streaked dwarf, grassy stunt viruses, as well as from “healthy” plants which were not inoculated with those viruses. The size and shape of the particles were also found in the dip preparations of the rice tarsonemid mites and eggs, Steneotarsonemus spinki Smiley (Acarina, Tarsonemidae). The mites were parasitic on the inside surface of the rice leaf sheaths, associating with brown discoloration. Antiserum against the 35nm particles purified from the sheaths after carefully removing the mites and eggs by brushing, reacted with the particles appeared in the dip preparations from the mites and eggs. The purified preparations of the 35nm particles showed typical absorption profile of nucleoprotein.
The particles were detected by ELISA in the leaf sheaths and in the hulls of rice grains, but not in the leaves, roots and paddy water. Ultrathin sections of the leaf sheaths revealed large amount of the 35nm particles in the inner epidermis and the adjacent parenchymatous cells. This is the first report of the virus-like particles associated with the tarsonemid mites that seems to propagate in the rice plants.
