First Report of Tomato Brown Rugose Fruit Virus Infecting Sweet Pepper (<i>Capsicum annuum</i>) in Open Fields in Uzbekistan

Tomato brown rugose fruit virus (ToBRFV) was first identified in Jordan in 2016 (Salem et al.,2016). Since its initial detection, the virus has rapidly spread to over 50 countries worldwide, posing a significant threat to tomato and pepper cultivation (EPPO, 2024). In 2024, the tomato variety "Alamina" cultivated under greenhouse conditions in Uzbekistan, was found to be infected with ToBRFV (Bakhtiyorova et al., 2024). Between January and August 2024, pronounced mosaic patterns were observed on the leaves of sweet pepper (Capsicum annuum) grown in both greenhouse and open field conditions in the Tashkent and Kibray districts of the Tashkent region. Additionally, affected fruits exhibited brown spots and deformation. Similar symptoms were noted in sweet pepper plants of the local cultivar "Dar Tashkenta" from open fields in the Taylok district of the Samarkand region. Field observations revealed that plants exhibiting these symptoms accounted for 25-30% of the monitored areas. Ten symptomatic leaves were collected from each of the three monitored fields (totaling 30 samples) and analyzed for ToBRFV using DAS-ELISA (Loewe Biochemica, Germany). All collected samples tested positive for ToBRFV. Further analysis involved RNA isolation using GeneJET Plant RNA Purification Mini Kit (Thermo Fisher Scientific, USA) from the 15 samples , with the presence of ToBRFV confirmed through reverse transcription polymerase chain reaction (by RT-PCR). Specific primers, ToBRFV_For (3'-CYATGGAACTATCAGAAGA-5') and ToBRFV_Rev (5'-ACTACCCTTCGATTTAAG-3') were designed to amplify an 829-bp fragment, encompassing the full nucleotide sequence (480 bp) of the coat protein synthesis gene of ToBRFV. The RT-PCR results conducted on 15 samples, confirmed through electrophoresis and visualization of the amplification product, corroborated the DAS-ELISA findings. One PCR product with a positive result was sequenced using the Sanger method. The obtained 799 bp long nucleotide sequence was analyzed via the BLAST program. The Tashkent isolate exhibited 96.12% nucleotide sequence identity with an isolate from China (OR795503) and 95.99% identity with isolates from Turkey (MT118666), the Netherlands (MN882064), Germany (OR843983), and Israel (KX619418). The sequences identified in this study have been deposited in the NCBI GenBank under accession number OR543967. The presence of ToBRFV in Uzbekistan has caused substantial reductions in tomato and sweet pepper yields, leading to significant economic losses. This study documents, the detection of ToBRFV previously reported in several countries, in sweet pepper plants in Uzbekistan. To our knowledge, this is the first report of ToBRFV infecting sweet pepper in Uzbekistan. These findings highlight the urgent need for strict adherence to plant protection and quarantine protocols to mitigate the spread and impact of the virus.