Results from a joint European research project show that seed transmission of Pepino mosaic virus (PepMV) in tomato, even though at a low level, is possible. The seed transmission rates differed from 0,005% until 0.057% depending on the time interval between PepMV infection and seed harvest. This means that the use of seeds harvested from PepMV infected plants bears the risk of obtaining PepMV infected seedlings. This conclusive indication of the PEPEIRA research project will be entered into the Pest Risk Assessment that will be one outcome of this research project.
PEPEIRA is a research project in the 6th framework programme of the EU, that aims at developing an EU-wide Pest Risk Assessment (PRA) for Pepino mosaic virus (PepMV) in tomato. The project studies the epidemiology and the economic impact of PepMV in order to provide a robust and scientifically sound assessment of the risk that PepMV poses to the European tomato industry. To unravel the highly debated, putative role of seed transmission in the spread of PepMV, an extensive trial on seed transmission has been carried out.
| More than 100,000 seeds were harvested from PepMV infected tomato plants in a Belgian greenhouse trial, following an International Seed Health Initiative approved seed harvesting procedure comprising acidification and enzymatic treatment. The virus inoculum was originally obtained from a commercial tomato crop, naturally infected by both the European tomato strain and the Chili2 strain of PepMV. |
Close up of Pepino mosaic virus (PepMV) in tomato |
The seeds were distributed to ten PEPEIRA consortium members from ten different countries and subsequently germinated and grown in glasshouses or plastic tunnels, in plots of 10 seedlings each. Between 4 and 5 weeks after germination, pooled leaf samples from each plot were collected and analysed for the presence of PepMV using a standardized ELISA method.
Nearly 90,000 tomato seedlings germinated and were included in the virus test. Twenty-three out of in total 8.778 plots (87.780 seedlings) tested were positive for PepMV, resulting in a average seed transmission rate of 0.026 %. The obtained PepMV seed transmission rates differed according to the time interval between PepMV infection in the mother plants and seed harvest. Seeds harvested 8 weeks after PepMV inoculation resulted in a seed transmission rate of 0,005%, while seeds harvested 15 weeks after PepMV inoculation resulted in a significantly higher transmission rate of 0,057%. Positive test results were confirmed by an additional ELISA-test. The results clearly show that seed transmission of PepMV can occur, even though at a low level, and that use of seeds harvested from PepMV infected plants bears the risk of obtaining PepMV infected seedlings.
This conclusive indication of seed transmission of PepMV, even though at a low level, will enter into the Pest Risk Assessment that will be one of the outcomes of the PEPEIRA project.
The Pepeira research project is a collaboration between 20 laboratories and institutions involved or dealing with plant health from 17 European Countries. More information about the consortium, the members and the research project: www.pepeira.wur.nl.