Detection and Molecular Characterization of Tobacco Mild Green Mosaic Virus on the Peony Paeonia wittmanniana

Tobacco mild green mosaic virus (TMGMV, genus Tobamovirus, family Virgaviridae) was detected for the first time on a new host plant, the peony Paeonia wittmanniana Hartwiss ex Lindl. The virus was found in the Botanical Garden of Moscow State University when studying the virome of a peony plant with wrinkling symptoms on the leaves using high-throughput sequencing. A virus-specific contig with a length of 6331 nucleotides was assembled. It represented a nearly complete sequence of the TMGMV genome, contained four open reading frames typical of tobamoviruses, and was most closely related (99.2% identity) to the TMGMV isolate from tobacco Nicotiana glauca (MT675965). The presence of the virus in the peony was confirmed by RT-PCR using virus-specific primers designed based on the whole genome sequence of the TMGMV peony isolate. Biological testing also revealed the presence of the virus in the analyzed plant. Mechanical inoculation of N. benthamiana by water extract from infected peony resulted in asymptomatic systemic TMGMV infection in inoculated plants. When N. glutinosa leaves were inoculated with an extract from infected N. benthamiana plants, small necrotic local lesions typical of TMGMV formed on them. This is the first report of TMGMV from peony in Russia, expanding the natural host range of this virus, adding the list of viruses infecting peonies and information on the geographical TMGMV distribution.