Single laboratory validation of a microsatellite marker-based method in tomato variety identification

Abstract

The objective of this study was to develop a systematic and flexible method for assembling multiplex simple sequence repeat marker panels for high-throughput genome analysis in the tomato, Solanum lycopersicum, for varietal identification and to demonstrate the technical viability of these genetic markers for use in the enforcement of U.S. Department of Agriculture marketing order-based identity preservation programs. GeneMapper, a semiautomated software tool, was used for designing multiplex panels, allele identification, and polymorphism pattern evaluation of diverse tomato cultivars. Semiautomated genotyping was performed on a set of 12 microsatellite markers providing genome-wide coverage of the tomato chromosomes. Microsatellites were detected with fluorescently labeled primers grouped into five multiplex panels, and each primer pair was assessed in replicated trials for reliability of allele size estimates. Allele sizes for each locus were compared, and a database for 34 tomato varieties was developed. The microsatellite marker set identified distinct allelic peaks and unique genetic fingerprints for each of the studied tomato varieties. A "blind testing" exercise with UglyRipe™ and Vintage Ripe™ tomato varieties, using the above set of markers and database, further established the usefulness of these microsatellite markers for tomato commodity marketing order enforcement.