Two virus cultures, RC4 and YC5, were isolated in Taiwan from calla lily (Zantedeschia spp.)
cv. Black magic displaying yellow spot and stripe on leaves. Both isolates were mechanically
transmitted to various hybrids of Zantedeschia and induced systemic symptoms similar to those
observed on diseased Black magic. In addition to Zantedeschia spp., the two virus isolates also
infected several cruciferous species and induced mosaic symptoms. Electron microscopy re-
vealed the presence of flexuous virus particles about 750 nm in length. The two isolates were
propagated in and purified from mustard plants and were used as immunogens for production of
antisera in rabbits. In enzyme-linked immunosorbent assay and sodium dodecyl sulfate-immu-
nodiffusion tests, both antisera reacted strongly with their homologous antigens and with anti-
gens of two Turnip mosaic virus (TuMV) isolates from radish (TuMV-R) and lisianthus (TuMV-
L), but not with 21 other different potyviruses tested. In reciprocal tests, antisera against TuMV-
R and TuMV-L also reacted strongly with RC4 and YC5 antigens, indicating that these two calla
lily isolates are serologically indistinguishable from other known TuMV strains. Cloning and
sequence analyses confirmed that both isolates shared 95 to 99% of deduced amino acid se-
quence identities in the coat protein genes with those of various known TuMV strains. This
investigation represents the first record of the natural infection of TuMV in calla lily.