Molecular characterization of a novel tobamovirus infecting hibiscus

Abstract

Full-length sequence of a new tobamovirus infecting Hibiscus rosa-sinensis L, Hibiscus Virus, Singapore isolate (HVS) was determined. The genome consists of a 5a?? untranslated region (UTR), regions encoding for methyltransferase-helicase, RNA dependent RNA polymerase (RdRP), movement protein (MP), coat protein (CP) and a unique 3a?? UTR. Phylogenetic trees generated based on the nucleotide and amino acid sequences of its open reading frames (ORFs) indicate that this new virus belongs to subgroup II of tobamoviruses. The unique feature in this new tobamovirus is the presence of a 3a??UTR that is different from other tobamoviruses. Studies directed towards understanding the translational strategies involved in expression of 3a?? proximal ORFs in HVS led to the identification of two putative IRES regions located immediately upstream of MP and CP ORFs. Preliminary investigations showed that both MP and CP IRESs are active in vitro in T7-based system and in vivo in agro-infiltrated tissues of Nicotiana benthamiana.