Co-infection of tomato brown rugose fruit virus and tomato spotted wilt virus in pepper from Iran

In a greenhouse complex located in the northwest of Iran, yellow-colored spots and deformation were observed on the fruit of bell pepper plants. Analysis of ten collected fruits showed the presence of both tomato brown rugose fruit virus (ToBRFV) and tomato spotted wilt virus (TSWV) viruses, indicating mixed-infection in three of the ten sampled pepper fruits. The S segment of TSWV was amplified using specific primers for the nonstructural protein (NSs), intergenic regions (IGR), and nucleocapsid protein (NP) gene. Sequence comparison of the coat protein (CP) gene of the ToBRFV isolate revealed that the new ToBRFV isolate formed a sister group with the previously reported Iran-1 isolate from Iran. Phylogenetic analysis of the S segment and its two ORFs (NSs and N) resulted in three groups. The analysis based on NSs and N protein sequences in RNA S showed that the Iranian TSWV isolate clustered in cluster I and formed a sister group with isolates from France and Iran. On the other hand, the analysis of RNA S segments revealed that the Iranian TSWV isolate clustered together with isolates from the USA, Turkey, and Italy. Transmission ability of the mixed virus sample was confirmed by mechanical inoculation of pepper and tomato plants. The plants showed a range of symptoms 15-25 days post inoculation (dpi).