Modern molecular methods for characterisation and diagnosis of seed-borne fungal pathogens

Current seed health testing is based on standardised methods described by International Seed Testing Association (ISTA) working sheets. Some of these tests are slow, insensitive and labour intensive. Molecular diagnostics offers the potential for sensitive and specific detection of pathogens and for detection of more than one pathogen in a single test by multiplex PCR and/or the use of fluorescent probes or primers. These methods are also suitable for automation and are thus more time and cost-effective than conventional methods. There are a multitude of primer sets designed from sequence characterised amplified regions (SCARS) and internal transcribed spacer (ITS) sequence data that have been published and developed for identifying plant pathogens. However, only a limited number of these have been developed into seed health tests. This may be partly due to technical difficulties, cost of PCR license and royalties as well as the time and organisation needed for test standardisation. In the near future it is anticipated that improved tests developed from current PCR/probe systems, and from future DNA chip technology, will help to reduce the amount of prophylactic seed treatment and improve management of seed-borne disease.