WP 3: PepMV characteristics and occurrence

Objectives of Work Package 3

  • To determine the most important biological and genetic characteristics of the different PepMV isolates and strains present in the different EU member states.
  • To develop and evaluate methods to accurately detect and diagnose all relevant PepMV strains and isolates.
  • To determine the occurrence and spread of the different PepMV isolates and strains over the different EU member states.
  • To determine the possible risks of PepMV strains and variants on tomato and other Solaneceous crops.
  • To accurately determine the risk of seed transmission in the spread of PepMV within the EU.

Basic summary of Work Package 3

Biological and genetic datasets of isolates and strains of PepMV are already available with the different partners in the consortium as well as in the international literature and databases. These data will be compiled and from their comparisons relevant biological and genetic characteristics of the different PepMV isolates and strains present in the EU member states will be determined. PCR-based methods will be developed that will allow both sensitive virus detection as well as distinction between different virus strains and isolates. All distinct PepMV isolates and strains will be preserved in a plant virus collection. This will ensure their future availability to science and industry for isolate and type virus comparisons both at the molecular and biological level, allow validation of diagnostics as well as durable plant resistance if it would become available through the breeding industry.

The field trials in WP2 will provide detailed information on the biological characteristics of PepMV type isolates on a single classic type tomato of a variety widely grown within the EU. A ‘ring test’ will be performed by at least 5 partners in which a panel of tomato varieties as well as a selected set of indicator plants will be mechanically inoculated with two or three type isolates of PepMV. In addition four agronomical important Solanaceous crop plants i.e. tobacco, potato, eggplant and pepper will also be mechanically inoculated. These experiments will provide information on the effects of local conditions and varieties on PepMV symptoms and their development during the growing season as well as on the potential risk new strains of the virus poses for these important crops widely grown in the different EU member states. The symptoms assessment scheme as developed in WP2 will be used to ensure conformity in symptoms recording by the different partners.

Developed serological and molecular diagnostics will be evaluated in ring tests by all consortium partners for their ability to accurately detect and diagnose all currently known PepMV isolates and strains using locally  available virus isolates and type virus isolates. This will both provide the basis for EU harmonization of test protocols and the development of an EPPO protocol. In addition these tests will also give insight in the genetic structure of PepMV populations in the different EU member states and the relative spread and importance of the different virus isolates and strains.

Mechanical transmission of PepMV is the main means of spread of the virus within and between countries. Practically virus transmission through infected seeds does not occur but its potential risk remains a point of discussion. Selected partners will therefore test levels of possible virus transmission through seed obtained from the plant mechanically inoculated with selected PepMV isolates.

Deliverables of Work Package 3

  • A report on the most important biological and genetic characteristics of the different PepMV isolates and strains present in the different EU member states.
  • An evaluation of methods to accurately detect and diagnose all relevant PepMV strains and isolates.
  • A report on the occurrence and spread of the different PepMV isolates and strains over the different EU member states.
  • An evaluation of the possible risks of PepMV strains and variants on tomato and other Solaneceous crops.
  • An evaluation of the possible risk of seed transmission in the spread of PepMV within the EU