The current Naktuinbouw ELISA technique is an effective and highly sensitive pre-screening method that is able to detect ToBRFV infection in tomato and pepper seeds, as well as ToMV and TMV. The ELISA cannot distinguish between infectious and non-infectious viruses.
Tomato brown rugose fruit virus (ToBRFV) is a relatively new tobamovirus that may be harmful to tomatoes and sweet peppers. ToBRFV is breaking the genetic resistances against tobacco mosaic virus (TMV) and tomato mosaic virus (ToMV) and is therefore potentially highly damaging.
Outbreaks of ToBRFV have been reported in Jordan, Israel, Mexico, Italy and Germany. Similar to all other tobamoviruses, ToBRFV, is very stable and can easily be spread via mechanical transmission. At present, there is no hard evidence to suggest that the virus is seed-transmissible.
Detection of ToBRFV in tomato seed using ELISA
ELISA is a rapid serological test that is used worldwide to detect various viruses on seed. Per lot of tomato seed, 3000 seeds in 12 subsamples of 250 seeds are being tested for the presence of ToMV and TMV. At Naktuinbouw, in the context of test validation, the current test was assessed to determine if it was sufficiently sensitive to ToBRFV. That appeared to be the case. The current Naktuinbouw ELISA was easily able to detect one seed infected with ToBRFV in subsamples of 250 seeds. ToBRFV is detected very efficiently by the current Naktuinbouw test by cross-reactivity with ToMV D / O3 antiserum. However, due to the cross-reactivity of the antiserum, it cannot distinguish between, for example, ToBRFV and ToMV.
Tobamovirus identification in the context of diagnostics
ELISA can easily detect tobamoviruses in seeds and leaves but cannot solve the question of the identity. Additional molecular analysis is necessary to identify the tobamovirus that has been found. This analysis can also be performed by Naktuinbouw.