Satoshi Kashiwazaki

Complete nucleotide sequence of wheat yellow mosaic bymovirus genomic RNAs

SummaryThe complete sequences of wheat yellow mosaic bymovirus (WYMV) RNAff1 and RNAff2 were determined. RNAff1 is 7 636 nucleotides long [excluding the 3′-poly(A)], and codes for a 269 kDa polyprotein of 2 404 amino acids which contains the capsid protein (CP) at the C terminus and seven putative non-structural proteins. RNAff2 is 3 659 nucleotides long and codes for a polyprotein of 904 amino acids which contains a 28 kDa putative proteinase and a 73 kDa polypeptide. These functional proteins are arranged as in RNAff1 and RNAff2 of barley yellow mosaic bymovirus (BaYMV). Comparisons with the sequence reported for the 3′ half of RNAff1 of wheat spindle streak mosaic bymovirus (WSSMV) from Southern France show that WYMV and WSSMV have a similar genetic organization. However, WYMV and WSSMV share only 77% amino acid sequence identity in their deduced CPs in spite of their close serological relationship, and 74% nucleotide sequence identity in their 3′ non-coding regions. Thus, the sequence data indicate that WYMV and WSSMV are not strains of the same virus, which has long been suggested, but are distinct virus species within the genus Bymovirus of the family Potyviridae.

Nucleotide sequence of the capsid protein gene of papaya leaf-distortion mosaic potyvirus

SummaryThe DNA complementary to the 3′-terminal 1 404 nucleotides [excluding the poly(A) tail] of papaya leaf-distortion mosaic potyvirus (PLDMV) RNA was cloned and sequenced. The sequence starts within a long open reading frame (ORF) of 1 195 nucleotides and is followed by a 3′ non-coding region of 209 nucleotides. Capsid protein (CP) is encoded at the 3′ terminus of the ORF. The CP contains 293 residues and has a Mr of 33 277. The CP of PLDMV exhibits 49 to 59% sequence similarity at the amino acid level to the CPs of papaya ringspot potyvirus (PRSV) and other potyviruses. This result is consistent with the absence of a serological relationship between PLDMV and PRSV or other potyviruses. The results support the assignment of PLDMV as a distinct member of the genusPotyvirus.

The 3' terminal sequence of RNA1 of wheat spindle streak mosaic virus canadian isolate (WSSMV-C)

The sequence of the 3′ terminal 1722 nucleotides (nts) of RNA1 of the type (Canadian) isolate of wheat spindle streak mosaic bymovirus (WSSMV-C) was determined. The sequence started within a single open reading frame (ORF), which was expected to encode the carboxyl terminus of the nuclear inclusion b protein (NIb) and the capsid protein (CP) of 294 amino acids, followed by a 3′ untranslated region (UTR) of 237 nucleotides. The NIb and CP of WSSMV-C share 99 and 100% amino acid sequence identity with the corresponding proteins of WSSMV-French isolate (WSSMV-F), but only 89 and 77% with wheat yellow mosaic virus (WYMV-J), respectively. The 3′UTR of RNA1 of WSSMV-C shares 94% nucleotide sequence identity with that of WSSMV-F but only 73% with WYMV-J and WYMV-Chinese isolate (WYMV-Chi). The results support the classification of WSSMV-C and WSSMV-F as strains of the same virus species which is distinct from WYMV.