Genome-Wide Characterization of Nuclear Microsatellite Markers for Centranthus trinervis (= Valeriana trinervis) and Cross-Amplification in Five Congeneric Taxa

Centranthus is a small genus belonging to the family Caprifoliaceae, comprising approximately 16 taxa (nine species plus seven subspecies). Currently, it is incorporated into the Valeriana genus, which is the most species-rich in the world (> 400 species), even though its phylogeny is not clear. Despite its botanical relevance, genetic markers for assessing the genetic diversity and population structure of its members are scarce, thus hindering the management and conservation of wild populations. In this study, we conducted a genome screening of the critically endangered C. trinervis to develop a set of nuclear microsatellite markers (SSRs) for population genetic studies across this species and five congeneric species. After data filtering, we selected 8747 contigs from which 100 primer pairs were tested in PCR. Amplification profiles returned 37 candidate microsatellites, with 13 proving informative for C. trinervis. These markers successfully cross-amplified in C. calcitrapae (9/13), C. lecoqii (7/13), C. longiflorus (9/13), C. nevadensis (8/13), and C. ruber (8/13). The observed high level of polymorphism and the favourable amplification rates in other congeneric species underscore the utility of these microsatellite markers as valuable tools for conservation and population genetic studies in a genus such as Centranthus or Valeriana.