Paulina Sepúlveda R.1
Among virus diagnostic techniques, double-stranded RNA (ds-RNA) analysis has been used for virus detection in fresh plant material, but its use in dehydrated leaves kept in freezer for several years, has not been mentioned. The objective of this study was to use ds-RNA analysis as a tool of diagnosis in the detection of virus infection in dehydrated bean leaves. Bean leaves dehydrated in calcium chloride and maintained in freezer (-20 ºC) for 10 years were subjected to ds-RNA extraction. The material (68 samples) was obtained from a survey of virus infected bean fields during 1982/83 season, in different locations of the metropolitan, VI and VII regions of Chile. The results obtained from ds-RNA analysis showed characteristic bands of virus groups, either in simple (88%) or mixed (12%) infections in the bean samples. According to the information of the ds-RNA analysis and ELlSA test, cucumber mosaic virus (CMV) was the virus found more frecuently on the samples (66%); a virus belonging to the potyvirus group (BCMV or BYMV or both) was present in 31 % of the samples. The present study was useful to demonstrate the efficiency of ds-RNA analysis as a diagnostic technique for the identification of virus infection in dehydrated plant material, and also to establish the presence of CMV affecting bean fields in Chile from 1983.
Key words: virus detection, ds-RNA, virosis, bean, electrophoresis, CMV, BCMV, BYMV.
1 Centro Regional de Investigación La Platina (INIA), Casilla 349, Correo 3, Santiago, Chile.