Survey of viruses infecting Solanaceous plants and characterization of Tomato brown rugose fruit virus (ToBRFV) infecting pepper in Egypt

Abstract

: This study investigated the incidence and occurrence of virus-like symptoms in solanaceous plants, peppers (Capsicum spp.), potatoes (Solanum tuberosum) and tomatoes (Solanumlycopersicum) in Egypt. In this study, a total of 640 samples collected from different Governorates in Egypt. 640 samples were tested using DAS-ELISA, with 86.87% of samples showing positive reactions. It was also, revealed that Potato virus Y (PVY) was the most prevalent virus (16.41%), followed by Potatoleafrollvirus (PLRV) (11.87%), Alfalfamosaic virus (AMV) and Pepper mild mottle virus (PepMMoV) both (10.94%), However, Tomato spottedwiltvirus (TSWV) was detected at low frequency (4.22%). Some samples were found coinfected with two or three different viruses (i. e. PVY+ ToMV, TMV+ PepMMoV+ TYLCV). Results demonstrated that potato was the most infected plans (37.65%) followed by tomato (27.97%) and then by pepper (21.25%). Potato was the most infected plant (37.65%), followed by tomato (27.97%), and then pepper (21.25%). Collected pepper leaf and fruit with negative results in all tested antisera were selected for identification the virus isolates which suggestive to be Tomatobrownrugosefruitvirus (ToBRFV) on the basis of symptomatology, host range, modes of transmission and particle morphology. RT-PCR was used to confirm the identity of the virus isolate. Among twenty-five plants species and cultivars, the virus isolate reacted positively with fourteen plants species. The virus was transmitted mechanically and by seed 1:2.5%. Examination of leaf tissue extracts of infected pepper plants by electron microscope revealed rod–shaped particles of 261-348 nm in length, in the range of the Tobamovirus group. Concerning varietal susceptibility, Helsinki and Mycelia pepper cultivars were highly susceptible (70%) followed by California Wonder (50%) and Vita Z 461 (40%). On the other hand, Vita Z Dragon cultivar was the lowest susceptible one (30%). RT-PCR analysis indicated that the virus isolate is ToBRFV.