Melon yellow spot virus: A Distinct Species of the Genus Tospovirus Isolated from Melon

Abstract

A tospovirus-like virus recovered from netted melon was transmitted by Thrips 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 RNA 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 also contained an eight-nucleotide sequence similar to the conserved sequence at the 3' end of genomic RNA molecules of tospoviruses. These features of the viral genome are identical to those of tospoviruses; therefore, this virus is considered to belong to the genus Tospovirus. Its N protein comprised 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 60% identity. This melon virus is concluded to be a distinct species in the genus Tospovirus, and the name Melon yellow spot virus is proposed.

The phylogeny of thrips (Thysanoptera: Thripidae) based on partial sequences of cytochrome oxidase I, 28S ribosomal DNA and elongation factor-1 α and the association with vector competence of tospoviruses

“…To test whether vector competence for Tospovirus is influenced by phylogenetic factors, we obtained partial sequence data from the mitochondria cytochrome c oxidase subunit I (COI) and two nuclear genes, the third domain (D3) of the ribosomal 28S locus (28S rDNA) and elongation factor-1a (EF-1a). We also compared the phylogenetic pattern of thrips vectors with that of the amino acid sequence of the nucleocapsid (N) protein of 16 tospoviruses reported previously (de Haan et al, 1990(de Haan et al, , 1992de Ávila et al, 1993;Pang et al, 1993;Satyanarayana et al, 1996Satyanarayana et al, , 1998Yeh et al, 1996;Cortês et al, 1998;Jain et al, 1998;Bezerra et al, 1999;Kato et al, 2000;Chu et al, 2001;Lee et al, 2002;Inoue et al, 2004b;Lin et al, 2005;Winter et al, 2006).…”

Melon yellow spot virus in watermelon: a first record from Taiwan

“…The sequence of this fragment was found to share 97% identity with that of the NSs gene of Melon yellow spot virus (MYSV), a virus previously reported from Japan (Kato et al ., 2000) and distinct from WSMoV.…”

The Present Status of Breeding and Germplasm Collection for Resistance to Viral Diseases of Cucurbits in Japan

“…Melon yellow spot virus (MYSV), a member of the genus Tospovirus, was first detected on diseased melon in Shizuoka Prefecture in 1992 (Kato et al, 2000), and on cucumber in Kochi Prefecture in 1995 (Takeuchi et al, 2001). The areas affected by MYSV are increasing, especially in the Kyushu, Shikoku, Tokai, and Kanto regions of Japan.…”

“…Melon yellow spot virus (MYSV; Kato et al, 2000), Papaya ringspot virus (PRSV; Iwasaki et al, 1992), Squash mosaic virus (SqMV; Yoshida et al, 1980), Watermelon mosaic virus (WMV; Iwasaki and 194 Inaba, 1988), Watermelon silver mottle virus (WSMoV; Iwaki et al, 1984), and Zucchini yellow mosaic virus (ZYMV; Iwasaki and Inaba, 1988) occur in cucurbitproducing areas in Japan. Many sources of cucurbit resistance to viruses have been reported, and foreign seed companies have already bred various resistant commercial cultivars.…”