Bottle gourd mottle virus isolate:WT2 Genome sequencing. Bottle gourd mottle virus isolate:WT2

A virus isolate (WT2) obtained from bottle gourd showing mottle symptom was identified to be a species of Tobamovirus. It was determined biologically and serologically distinct from other known tobamovirus at least those infecting cucubits. This project is aiming at revealing the genome organization of this newly found virus isolate. By cloning and sequencing eleven different regions of the full length genome of WT2 isolate, a complete sequence with 6498 nucleotides was obtained. The genome encodes four open reading frames (ORF1-4) that could be translated into four functional viral proteins. The ORF1 containing 3501 bp can be translated into a putative 128 kDa replication protein. A 185 kDa readthrough protein containing ORF1 and ORF2 also functions as replication protein of virus RNA. The next ORF3 (789 bp) and ORF4 (489 bp) encode a 29 kDa movement protein (MP) and a 18 kDa coat protein (CP), respectively. Interestingly, MP ORF region overlaps both the ORF2 and CP ORF. This genome organization is the same as those of other reported species of Tobamovirus family. Comparing with the tobamovirus sequences documented in the GenBank, Cucumber mottle virus is the one with highest nt sequence similarity of 80-85% with WT2. Based on the species demarcation criteria of tobamoviruses, sequence difference within the same species should be less than 10% so that WT2 is considered as a separate unique species of the genus Tobamovirus. It is therefore designated as Bottle gourd mottle virus (BGMoV) based on its specific mottle symptom expressed in bottle gourd.