A Viroid Resembling Hop Stunt Viroid in Grapevines from Europe, the United States and Japan

Abstract

Summary A viroid (GV) was isolated from grapevines recently introduced into Japan from France, West Germany, Austria, Hungary and U.S.A., as well as from those cultivated in Japan. It was detected in 28 out of 32 (88%) grapevines tested. The isolates of GV had similar host ranges and induced symptoms in cucumber plants identical to those induced by hop stunt viroid (HSV). The nucleotide sequences of four GV isolates, from France, West Germany, Hungary and Japan, were identical and these formed covalently closed circular molecules 297 nucleotides in length. This sequence differed from that of HSV in one nucleotide only and from that of the cucumber isolate of HSV in being six nucleotides smaller and having 15 nucleotides different (95% sequence homology). The result indicates that GV is a grapevine isolate of HSV and suggests that grapevines were the source of hop stunt disease in Japan.