Sap-transmissible Virus Research Articles

Studies on Virus Diseases of Stone Fruits I.

Sap transmissible viruses were isolated from peach var. Nakayamakinto and sour cherry var. Montmorency provisionally laveled isolate-1 and -2.When buds from Nakayamakinto were used to infect the seeedlings of Prunus species, they induced necrotic ringspot in Mazzard, no symptom in mahaleb, top necrosis of young shoots in flowering cherry var. Magofugen and necrosis and gummosis in var. Shirofugen. Isolate-1 caused chlorotic ringspot and top necrosis in cucumber, chlorotic ringspot on inoculated leaves but not infected systemically in squash, vein necrosis on inoculated leaves and necrotic stem streak in asparagus bean and local chlorotic spot and mottle in Chenopodium amaranticolor. This isolate had a thermal inactivation point of 50-55°C, a dilution end point between 1/100 and 1/500 and longevity was 7-10 hours.In the case that Montmorency was used for inoculum to seedlings of Prunus species it caused dwarf in mahaleb, necrosis and gummosis in Shirofugen and no symptom in Mazzard and Magofugen. When isolate-2 was used for inoculum, cucumber reacted with mild chlorotic spot on inoculated cotyledons and with mosaic and marformation on young leaves. Squash, tobacco and zinnia were systemically infected with isolate-2 and produced bright yellow vein banding and mosaic on squash and chlorotic ring or mottle on tobacco and zinnia. The thermal inactivation point of isolate-2 was 45-50°C, dilution end point was between 1/50 and 1/100 and longevity was 4-5 hours.On the basis of these host ranges, symptomatology and physical properties isolate-1 was identified as peach necrotic ringspot virus (NRSV) and isolate-2 was identified as prune dwarf virus (PDV).

Electron microscopic observations on the apparent replication in vivo of a plant virus

An account is given of a new sap-transmissible virus of the mosaic type affecting Lantana horrida H.B.K., Verbenaceae. In mesophyll cells of young infected leaves four apparent stages in the replication in vivo of the long virus rods have been observed. These consist of sheets of crystalline material; long clearly defined helices which seem to detach from the crystalline material; helices partly covered with a coat and therefore appearing like hollow rods; and the mature virus rods. The latter three stages are all approximately the same diameter and length. Replication takes place simultaneously and apparently independently in both the nucleus and cytoplasm. Measurements of the virus rods in situ suggest a length of 1400 mμ or more and a diameter of between 14 and 15 mμ. The mature virus rods are present in arrays that may show hexagonal packing; the individual rods appear to be hexagonal in shape when viewed in transverse section.

Sap-Transmissible Viruses Associated With Diseases of Grape Vines in Europe and North America

Sap-Transmissible Viruses Associated With Diseases of Grape Vines in Europe and North America