Detection of Fiji disease virus in sugarcane by ELISA

Abstract

A direct double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was developed for the detection of Fiji disease virus (FDV) in sugarcane (Saccharum spp. hybrid) cultivars NCo310 and CP44-101. Optimal results were obtained when Dynatech microplates, coated with 2 ¦g/mL FDV-specific immuno-gamma globulin (IgG) coupled with alkaline phosphatase-lgG conjugate at a concentration of 1/1000, were used. The test could detect FDV in crude extracts (fresh or frozen) of gall and gall-free infected tissues with an end point dilution of 1/5000 and 1/1000, respectively. The FDV antibody showed a high degree of specificity and failed to react with 3 other field-associated sugarcane viruses. When the distribution of FDV within the plant was studied, the highest titre was found in the basal axillary buds decreasing towards the top of the plant and into the roots. However, the apical meristem produced a virus titre significantly higher than any adjacent axillary buds. The ELISA was well suited for large-scale screening programs and its potential was further extended to quarantine work since it could be used to identify the virus in frozen, non-galled tissues.