Comparison of eight isolates of beet yellows virus by filter hybridisation and enzyme-linked immunosorbent assay

An improved method of virus purification was developed for beet yellows virus (BYV), which resulted in higher virus yields and fewer broken particles than from other methods. Double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was not able to differentiate eight isolates of BYV, but filter hybridisation analyses, using cloned cDNA from one of the isolates as the probe was successful in distinguishing some of these isolates. The degree of hybridisation did not correlate with the severity of the symptoms associated with infection by isolates. Therefore, hybridisation cannot be used as a means of predicting symptom severity. The hybridisation data also indicated that the isolates consisted of stable mixtures of strains. Cross-hybridisation of clones derived from one isolate indicated that certain areas of the BYV genome cloned preferentially to other areas.