- Volume 66, Issue 2, 1985

Viroid-like RNA was isolated from some samples of grapevine leaves (Vitis vinifera L.). When inoculated to cucumber, this RNA induced symptoms that were identical to those induced by hop stunt viroid (HSV). It had a molecular size similar to that of HSV, and hybridized with a 32P-labelled DNA probe for the cucumber isolate of HSV (HSV-c, pCP-55). This hybridization suggests high (> 55%) sequence homology with HSV. The HSV-related sequence was detected not only in the infected cucumber plants but also directly in RNA extracted from grapevine plants. The result indicates that viroid-like RNA, closely related to HSV, is present in grapevines in Japan.

Dot blots of dsRNA from European and American hypovirulent (H) strains of the chestnut blight fungus, Endothia parasitica, were hybridized with 32P-5′-end-labelled fragments of denatured dsRNA of French, Italian and American origins. Although dsRNA from European or American strains reacted well with labelled RNA probes from strains from the same continent there was little or no cross-hybridization between RNA from strains from different continents.