Genomic Analysis of a Novel Torradovirus “Rehmannia Torradovirus Virus”: Two Distinct Variants Infecting Rehmannia glutinosa

<i>Rehmannia glutinosa</i>, a crucial medicinal plant native to China, is extensively cultivated across East Asia. We used high-throughput sequencing to identify viruses infecting <i>R. glutinosa</i> with mosaic, leaf yellowing, and necrotic symptoms. A novel <i>Torradovirus,</i> which we tentatively named "Rehmannia torradovirus virus" (ReTV), was identified. The complete sequences were obtained through reverse-transcription polymerase chain reaction (RT-PCR), 5' and 3' rapid amplification of cDNA ends, and Sanger sequencing. The amino acid sequence alignment between the ReTV-52 isolate and known <i>Torradovirus</i> species in the Pro-Pol and coat protein regions were 51.3-73.3% and 37.1-68.1%, respectively. Meanwhile, the amino acid sequence alignment between the ReTV-8 isolate and known <i>Torradovirus</i> species in the Pro-Pol and coat protein regions were 52.7-72.8% and 36.8-67.5%, respectively. The sequence analysis classified ten ReTV strains into two variants. The ReTV-52 genome has two RNA segments of 6939 and 4569 nucleotides, while that of ReTV-8 consists of two RNA segments containing 6889 and 4662 nucleotides. Sequence comparisons and phylogenetic analysis showed ReTV strains clustered within the <i>Torradovirus,</i> exhibiting the closet relation to the squash chlorotic leaf spot virus. The RT-PCR results showed a 100% ReTV detection rate in all 60 <i>R. glutinosa</i> samples. Therefore, ReTV should be classified as a novel <i>Torradovirus</i> species. ReTV is potentially dangerous to <i>R. glutinosa,</i> and necessitating monitoring this virus in the field.