A panel of 30 monoclonal antibodies (MAbs) was produced against four isolat
es of turnip mosaic virus (TuMV). The panel was tested in plate-trapped ant
igen ELISA tests against 41 TuMV isolates (with different host and geograph
ical origins and of differing pathotypes). The antibodies were also tested
against four other potyviruses (bean common mosaic virus, bean common mosai
c necrosis virus, lettuce mosaic virus and zucchini yellow mosaic virus). T
he reactions were assessed quantitatively (using multivariate analysis) and
qualitatively (using the standard deviation obtained against healthy leaf
material). The MAbs recognized 16-17 TuMV IV epitopes that were not present
in the other potyviruses and a further two potyvirus epitopes. The isolate
s were grouped into three serotypes. Only one isolate did not fit this grou
ping. The classification of seven isolates in coat protein amino acid seque
nce homology groups correlated with serotypes. There was no correlation bet
ween serotype and pathotype, or between reactions to individual MAbs and si
ngle lines. There was therefore no evidence that the epitopes recognized by
the MAbs are elicitors for the resistance genes present in the Brassica na
pus lines. However, the sensitivity and specificity of the MAbs will be use
ful for both routine detection of TuMV and fundamental studies on plant-vir
us interactions.