Serendipitous identification of a new Iflavirus-like virus infecting tomato and its subsequent characterization

Abstract

The genomic sequence of a previously undescribed virus was identified from symptomless tomato plants (Solanum lycopersicum). The viral genome is a positive-sense ssRNA molecule of 8506 nucleotides. It is predicted to encode a single polyprotein of 314·5 kDa that is subsequently processed into three coat protein components of 13·7, 17·9 and 13·5 kDa, and a viral replicase of approximately 207 kDa with conserved motifs for a helicase, a protease and RNA-dependent RNA polymerase (RdRp). Pairwise analysis of the deduced amino acid sequence of the RdRp revealed that it shares closest identity with members of the family Iflaviridae, genus Iflavirus (19-47% identity). Evidence of replication in plants was detected by RT-PCR of the viral replicative strand, and short interfering RNAs (siRNAs) matching the virus. The name Tomato matilda virus (TMaV) is proposed, and furthermore, that the genus Tomavirus (Tomato matilda virus) be created within the family Iflaviridae. This is the first report of a plant-infecting virus resembling members of the Iflaviridae.