Virus diseases of Japanese anemone.

Two viruses, Tobacco rattle virus (TRV), genus Tobravirus and Raspberry ringspot virus (RRSV), genus Nepovirus, have been isolated from plants of Japanese anemone (Anemone x hybrida = Anemone hupehensis var. japonica x A. vitifolia) growing in nurseries in southern Germany and in north western Italy. TRV was detected, in the samples checked in Italy, by one-step RT-PCR using TRV-specific primers and total RNA as template. On indicator plants, the four isolates studied induced disease characteristic of TRV infection. Two of the isolates formed typical tobravirus particles. The other two caused milder symptoms on indicators and no virus particles were seen in these plants; these isolates were assumed to be of the MN-type, lacking the gene for the coat protein. RRSV was detected in one sample tested in Germany and in one of the samples collected in Italy. This last was freed from mixed infection with TRV by using Chenopodium quinoa as differential host. The experimental host range of both German and Italian isolates was in agreement with what is known for RRSV. Both isolates were identified by electron microscopy decoration, using antisera to five RRSV isolates. In comparative tests, titres of four of these antisera were almost identical for both isolates, while the fifth antiserum, to the Italian isolate, differentiated between the two isolates. No reaction occurred with antisera to 22 other nepoviruses, four fabaviruses and five comoviruses. A major coat protein of Mr slightly over 50 kDa and two RNA species of about 8 kb (RNA1) and 4 kb (RNA2) were found for the Italian isolate.