Studies On The Genome Structure And Biologic Characteristics Of Rehmannia Mosaic Virus

ReMV(Rehmannia mosaic virus), isolated by our laboratory from Dihuang, is probably a new specie of Tobamovirus. On the foundation of early study that have done, the 5' end and 3' end nucleotide sequences was obtained. The full length genome sequence was confirmed and analysised. The classfication of ReMV was further confirmed. Subsequently, its host range, thermal inactivation point (TIP), dilution end point (DEP),the longevity in vitro (LIV) and morphology were studied.5'end sequence of 71 nucleotides and 3'end sequence of 204 nucleotides were obtained by RACE-PCR.Full length genome sequence of ReMV was finally confirmed, and the results show that ReMV genome has 6395 nucleotides, with 72 nucleotides and 203 nucleotides at 5'end and 3'end non-translated regons. The genome includes four open reading frame(ORF),which encode 126KD protein, 183KD protein, movement protein and coat protein respectively. 126KD protein ORF starts at the 72nt,stop at the 3422nt;183KD protein ORF starts at the 72nt,stops at the 4922nt; movement protein ORF starts at the 4906nt,stop at the 5709nt;coat protein ORF starts at the 5712nt,stop at the 6191nt. ReMV shares the highest identity with TMV-U1, full length genome similarity between ReMV and TMV-U1 is 83%,which between other tobamoviruses is 45%-78%. Nucleotide sequence identities and amino acid sequence identities of 126KD protein ORF between ReMV and other tobamoviruses is 44%-82% and 32%-93%;which of 183KD protein ORF is 48%-83% and 43%-94%;which of movement protein PRF is 36%-80and 19%-85%;which of coat protein ORF is 41%-85% and 34%-94%. Identities of 5'end and 3'end non-translated region between ReMV and other tobamoviruses is 52%-92% and 51%-94% respectively. Genome structure analysis shows that ReMV is a new subgroupI tobamovirus and the virion origin of assembly is located in the CP ORF,for its MP and CP ORFs are separated by two nucleotides.According to the report of Gibbs, the 4404-4450 motif of ReMV was analysised and compared with those of other tobamoviruses. Results show that its 4404-4450 motif is identical to the conserved genus-specific site of Tobamovirus,so ReMV belongs to Tobamovirus. However,it is different with that of TMV,ToMV,or other Tobamoviruses. So ReMV is probably a new specie.