Infectivity test and serological relationships among various isolates of cucumber green mottle mosaic virus; some deduction of the invasion route of the virus into Japan

Abstract

To deduce the possible invasion route of cucumber green mottle mosaic virus (CGMMV) into Japan, comparative studies of infectivity and two serological tests by the agar gel double diffusion, and the reciprocal relations of precipitation end points of absorbed and unabsorbed antisera with homologous and heterologous antigens were made with three isolates of Japanese CGMMV (Wa, Cu, and Y), two isolates (E1 and E2) from England, supplied by L.J. Cock, and one isolate (C) from India, supplied by S.P. Raychaudhuri. Tomato strain (T) and ordinary strain (OM) of TMV were also included in serological studies.Four isolates; Wa, C, E1 and E2, had strong similarities in the infectivity and serological relationships with one another (Table 1-3). However, the precipitin bands showed a distinct spur reaction, indicating some serological differences between the following combination of the isolates; Wa-E1, Wa-E2, C-E1, and C-E2 (Fig. 1). Wa closely resembled C in the infectivity and serological tests, which suggested that Wa and C were virtually identical virus strain. Bottlegourd seeds have been imported frequently from India to Japan and occurrences of watermelon fruit's deterioration coincided with the importation of the seeds. It was deduced that Wa was most probably introduced to Japan by means of the seeds infected with the virus. Cu differed markedly in the infectivity and serological relationship from these four isolates, and isolates similar to Cu were not found.