Detection of Tomato brown rugose fruit virus (ToBRFV) in solanaceous plants in Mexico

Tomato brown rugose fruit virus (ToBRFV) is a novel tobamovirus initially reported in Jordan and Israel, and, more recently, in Europe, China, the USA and Mexico, which causes severe symptoms in tomato and pepper, as well as in other members of Solanaceae. ToBRFV can cause important losses so early detection is crucial to help thwart its dispersal, more so in countries where this virus is emerging as an important pathogen, as is the case in Mexico. Therefore, precise diagnostic is required to distinguish this virus from other members of this family that are not quarantined. We have analyzed the sequence of ToBRFV and compared to several other tobamoviruses and identified regions that are amenable for specific primer design. Regions in the replicase (p126 and p183), movement and coat proteins (MP and CP, respectively) genes were selected. Preliminary results indicated that CP primers provided the most consistent results. Furthermore, these primers were also used to detect ToBRFV via real-time qRT-PCR in leaf samples from tomato. The method was used successfully to detect 20 copies of viral transcript.