A tospovirus-like virus recovered from netted melon was transmitted by Thri
ps palmi in a persistent manner but had different cytopathological features
from tospoviruses previously reported. Viral nucleocapsid (N) was purified
with two protective reagents, 2-mercaptoethanol and L-ascorbic acid, and R
NA extracted from the viral nucleocapsid was used for genomic analysis. The
virus had a genome consisting of three single-stranded RNA molecules. The
open reading frame on the viral complementary strand, located at the 3' end
of the viral S RNA, encoded the N protein. The 3' terminus of this RNA als
o contained an eight-nucleotide sequence similar to the conserved sequence
at the 3' end of genomic RP FA molecules of tospoviruses. These features of
the viral genome are identical to those of tospoviruses; therefore, this v
irus is considered to belong to the genus Tospovirus. its N protein compris
ed 279 amino acids and had a molecular mass of 31.0 kDa. Comparisons of its
amino acid sequence: with those of known tospoviruses revealed less than 6
0% identity. This melon virus is concluded to be a distinct species in the
genus Tospovirus, and the name Melon yellow spot virus is proposed.