SINGLE-STRAND CONFORMATION POLYMORPHISM ANALYSIS OF RT-PCR PRODUCTS OF UK ISOLATES OF BARLEY YELLOW MOSAIC-VIRUS

Single-strand conformation polymorphism (SSCP) analysis of the biparti te genomes of several UK isolates of barley yellow mosaic virus (BaYMV ) was done using fragments of cDNA amplified by RT-PCR. Isolated diffe red in their SSCP patterns in several regions, but in no case was the pattern able to distinguish between common and resistance-breaking str ains. In regions where the nucleotide sequences of UK isolates had bee n determined, there was no simple relationship between numbers of nucl eotide differences and SSCP patterns: differences of only 2 or 3 nucle otides (nt) gave different SSCP patterns, whereas differences of as ma ny as 29 nt did not. Although SSCP analysis has some potential as a ra pid and sensitive tool for distinguishing virus isolates, differences detected do not necessarily relate to biological properties and the re sults are highly dependent on gel conditions.