Development, characterization, and transferability to other Solanaceae of microsatellite markers in pepper (Capsicum annuumL.)

Abstract

A novel set of informative microsatellite markers for pepper (Capsicum annuum L.) is provided. Screening of approximately 168 000 genomic clones and 23 174 public database entries resulted in a total of 411 microsatellite-containing sequences that could be used for primer design and functional testing. A set of 154 microsatellite markers originated from short-insert genomic libraries and 257 markers originated from database sequences. Of those markers, 147 (61 from genomic libraries and 86 from database sequences) showed specific and scoreable amplification products and detected polymorphisms between at least 2 of the 33 lines of a test panel consisting of cultivated and wild Capsicum genotypes. These informative markers were subsequently surveyed for allelic variation and information content. The usefulness of the new markers for diversity and taxonomic studies was demonstrated by the construction of consistent phylogenetic trees based on the microsatellite polymorphisms. Conservation of a subset of microsatellite loci in pepper, tomato, and potato was proven by cross-species amplification and sequence comparisons. For several informative pepper microsatellite markers, homologous expressed sequence tag (EST) counterparts could be identified in these related species that also carry microsatellite motifs. Such orthologs can potentially be used as reference markers and common anchoring points on the genetic maps of different solanaceous species.