The complete nucleotide sequences of Beet pseudoyellows virus (BPYV)-MI (cucumber isolate; Matsuyama, Idai) genomic RNAs 1 and 2 were determined and compared with the previously sequenced Japanese cucumber strain (BPYV-JC) and a strawberry strain (BPYV-S). The RNA 2 of BPYV-MI showed 99 % nucleotide sequence identity with both BPYV-JC and -S having highly conserved eight ORFs. In contrast, the RNA1 of BPYV-MI showed sequence identities of 98 and 86 % with BPYV-JC and -S, respectively. Phylogenetic analysis of RNA-dependent RNA polymerase (RdRp) coding sequences from three fully sequenced BPYV strains and five partially sequenced cucurbit-infecting BPYV strains from Japan and South Africa has shown that cucurbit-infecting strains are closer to each other than to BPYV-S. In addition, the strawberry strain BPYV-S has an ORF2 in the downstream of RdRp gene in RNA1, but all the cucumber strains, BPYV-JC, -MI, and those from South Africa, lacked the ORF2 of RNA1, highlighting the difference between common BPYV cucumber strains and a unique strawberry strain.
Keywords: BPYV; Crinivirus; Cucumber; Host adaptation; Strawberry.