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POSTERS: Pathogen detection, quantification and diagnosis

Reliable detection and identification of Tomato brown rugose fruit virus (ToBRFV) and other tobamoviruses in seeds of solanaceae.
Gerbert Hiddink - Enza Zaden Seed Operations BV. Sukhi Pannu- CSP Labs, Bart Geraats- Nunhems Netherlands B.V., Debby Beugelsdijk- Enza Zaden Seed Operations BV, Carla Tavares- Enza Zaden Seed Operations BV, Merel Langens- Nunhems Netherlands B.V., Radha Ranganathan- International Seed Federation

First occurrence of ToBRFV on commercial scale was in Jordan in 2014. The virus, which overcame Tm-22 resistance that has effectively controlled tobamoviruses in tomato for decades, is a threat to solanaceae seed and produce industries. Spread of tobamoviruses by solanaceae seed is prevented by testing representative seed samples and disinfecting infected seedlots. Tobacco plants are used as an indicator for presence of viable virus in solanaceae seed and if seed is infected with a tobamovirus, leaves inoculated with the seed extract develop small necrotic lesions. ELISA can be used as prescreen and if no virus is detected by ELISA the seedlot is considered free from tobamoviruses. However, as ELISA detects both infectious and non-infectious virus particles, the indicator plant test should follow after a positive ELISA to determine the presence of infectious tobamovirus. Some countries require specific testing for ToBRFV and a PCR test on symptomatic leaves in the indicator plant test can identify the virus, if present. PCR tests on seed extract after a positive ELISA prescreen can also identify the virus. For the vegetable seed industry it is crucial that all tobamoviruses associated with solanaceae seed are detected in seed health tests. The seed industry is developing and adopting new methods. These methods must be as robust and reliable as the indicator plant test and ELISA prescreen have been in preventing tobamovirus outbreaks for many decades.