Transcriptome sequencing and simple sequence repeat marker development for three Macaronesian endemic plant species.

PREMISE OF THE STUDY Oceanic islands offer unparalleled opportunities to investigate evolutionary processes such as adaptation and speciation. However, few genomic resources are available for oceanic island endemics. In this study, we publish transcriptome sequences from three Macaronesian endemic plant species (Argyranthemum broussonetii [Asteraceae], Descurainia bourgaeana [Brassicaceae], and Echium wildpretii [Boraginaceae]) that are representative of lineages that have radiated in the region. In addition, the utility of transcriptome data for marker development is demonstrated. METHODS AND RESULTS Transcriptomes from the three plant species were sequenced, assembled, and annotated. Between 1972 and 2282 simple sequence repeats (SSRs) were identified for each taxon. Primers were designed and tested for 30 of the candidate SSRs identified in Argyranthemum, of which 12 amplified well across three species and eight were polymorphic. CONCLUSIONS We demonstrate here that a single transcriptome sequence is sufficient to identify hundreds of polymorphic SSR markers. The SSRs are applicable to a wide range of questions relating to the evolution of island lineages.