ISHS Acta Horticulturae 431: Tospoviruses and Thrips of Floral and Vegetable Crops
GROUPING OF FIVE TOSPOVIRUS ISOLATES FROM JAPAN |
| Authors: | S. Tsuda, M. Kameya-Iwaki, K. Hanada, K. Tomaru, Y. Minobe |
| Abstract:
Five isolates of tospoviruses N (tomato), M (tobacco), P (green pepper), W (watermelon), and K (white gourd) were collected in different prefectures in Japan and characterized on the basis of nucleocapsid (N) protein and S RNA. The nucleocapsids of each isolate were purified by ultracentrifugation using a metrizamide isopycnic density-gradient. The molecular weights of the N proteins of isolates N, M, and P were 30 kDa; whereas, the N proteins of isolates W and K were 32 kDa. Antibody to N protein reacted with isolates N, M, and P, but antibody to W reacted only with W and K. Monoclonal antibodies reacted to a species-specific antigenic determinant, as well as to a common one. The molecular weight of the S RNAs of N, M, and P was 1.02 x 106; for W and K it was 1.21 x 106. S RNA from the N isolate hybridized with N, M, and P, and S RNA from W hybridized only with W and K. Nucleotide (nt) sequence analysis of S RNA (N-protein gene) indicated that the P isolate had 97% homology with tomato spotted wilt virus (TSWV); whereas, the sequence of the N gene of isolate W or K shares 97% homology to that of watermelon silver mottle virus (WSMC). These results indicate that the five tospovirus isolates from Japan represent two species, tomato spotted wilt virus (N, M, and P) and watermelon silver mottle virus (W and K). | |
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