First report of tomato brown rugose fruit virus on tomato (Solanum lycopersicum L.) in Uzbekistan

Tomato (Solanum lycopersicum L.) is one of the main agricultural crops cultivated on 60,000 hectares in Uzbekistan. Tomato brown rugose fruit virus (ToBRFV), a recently identified tobamovirus, was initially reported in Jordan (Salem et al. in 2016). Since its discovery, this virus has posed a significant threat to tomato and pepper crops worldwide. In spring 2021, and during an official survey for tomato diseases in Uzbekistan, viral symptoms that resemble those caused by ToBRFV (mosaic and discoloration symptoms on the leaves and brown spots on the fruits) were observed on greenhouse-cultivated tomato plants of cultivar ‘Alamina' in Zangiota, Qibray and Chirchiq districts, Tashkent region. Incidence of symptomatic plants ranged from 15 to 20% in the three visited locations. Leaf samples were collected from 30 symptomatic (10 per location) and 6 asymptomatic plants and analyzed by DAS-ELISA with antibodies to ToBRFV, pepino mosaic virus and tomato spotted wilt virus, (Loewe Biochemica, Germany). All symptomatic plants tested positive for ToBRFV only. Furthermore, total RNA was extracted from selected ELISA-positive samples, and the presence of ToBRFV was further confirmed by RT-PCR using ToBRFV-F/ToBRFV-R (Alkowni et al. 2019) and F-3666/R-4718 (Luria et al. 2017). To ascertain the nature of the amplified DNA, one representative RT-PCR amplicon was sequenced in both directions, and the sequence was deposited in GenBank as accession number OR501605. Bioinformatics and BLAST analysis of the sequenced amplicon showed 100% nucleotide identity with ToBRFV isolates from the USA, Turkey and the Netherland (MT002973, MT107885 and MN882058, respectively). Very likely, ToBRFV was introduced to Uzbekistan on imported ‘Alamina’ seeds that were infected. To our knowledge, this is the first report of ToBRFV in Uzbekistan.