Molecular characterisation of an unidentifiel Flexivirus
2004
Teycheney, Pierre-Yves | Marais, Armelle | Svanella-Dumas, Laurence | Candresse, Thierry
Phylogenic studies undertaken on Banana mild mosaic virus (BanMMV) populations led to the characterisation of a 230 nt sequence originating from a yet unidentified virus in one of the 69 accessions analysed. No visible symptom was associated with the presence of this virus. 3' RACE experiments were performed on double stranded RNAs purified from this accession, enabling the cloning and sequencing of about 2.3 kb of the 3' end region of the genome of this virus. Based on sequence comparisons, the analysis of the cloned sequence showed the presence of 5 open reading frames (ORFs) encoding an RNA dependent RNA polymerase (RdRp), three proteins involved in virus movement and organised as a triple gene block (TGB1, TGB2 and TGB3) and a coat protein, respectively. The genomic RNA ends in a short 3' non-coding region followed by a polyA tail. Sequence comparisons and phylogenic analyses performed on both nucleotide and amino acid sequences led to the conclusion that this virus, tentatively named Banana X virus (BanXV) seems to represent a new agent since it shows only distant relationships with viral sequences present in databanks. It probably belongs to a new genus within the Flexiviridae family and is very distantly related to members of other genera in this family such as the genus Foveavirus. Results of further molecular work aimed at unravelling BanXV expression strategy will also be presented and discussed (Texte intégral).
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