Abstract
Mosaic plants of annual bluegrass, Poa annua L., and soil sample are collected from a barley field in Tottori. X-bodies were found in the epidermal strips of diseased leaves. Electron microscopic examination of leaf-dip preparation revealed rod-like particles measuring 110-160×25mμ. Inoculation with the sap of mosaic annual bluegrass plants effected infection of not only annual bluegrass but also wheat, as determined by mosaic symptoms, and presence of X-bodies and rod particles. Back inoculation from infected wheat to annual blugrass was successful.
There was no evidence of virus transmission through seed. Soil transmission of the virus to annual bluegrass and wheat, however, was proved by sowing the seed in the infested soil or by immersing the germinated seeds for 15 days in water mixed with infested soil. Virus was partially purified by differential centrifugation from sap clarified with chloroform and dihydrostreptomycin-sulfate. This virus preparation reacted well with a soil -borne wheat mosaic virus antiserum in complement fixation tests. Resting spores of Polymyxa graminis were found in the roots of naturally infected annual bluegrass.
From these results, the virus from Poa annua was identified as soil-borne wheat mosaic virus. Annual bluegrass, a new host, may play some role in the spread of soil-borne mosaic disease of cereals in the field.
