DNA Barcoding and Comparative Chloroplast Marker Performance in Endemic Plants of Crete (Greece)

Crete, a major Mediterranean biodiversity hotspot, hosts many local endemic, threatened and/or protected plant taxa (species and subspecies). Besides their ecological and conservation significance, these unique phytogenetic resources hold significant economic potential for sustainable utilization. Since DNA barcoding is critical for conservation, taxonomy, and plant-derived product authentication, we studied 15 local Cretan endemic taxa using three chloroplast DNA (cpDNA) regions (rbcL, trnL, trnH-psbA). A comparative analysis against GenBank (NCBI) records revealed significant new data: (i) the first genetic information for five taxa (Centaurea redempta subsp. redempta, Galium fruticosum, Micromeria hispida, Salix kaptarae, Teucrium cuneifolium); (ii) new marker-specific sequences for seven taxa (Helichrysum heldreichii, Scutellaria hirta, Sesleria doerfleri, Staehelina petiolata, Teucrium alpestre, Campanula pelviformis, Phlomis lanata); and (iii) novel genotypes of already represented markers for three species (Phlomis lanata, Scutellaria sieberi, Staehelina petiolata). Phylogenetic analyses were performed for all three molecular markers across selected members of Scutellaria section Scutellaria, Teucrium section Polium, and Campanula section Quinqueloculares. The overall results indicated that, amongst the studied species, the trnH-psbA marker is more suitable for species-level identification, whereas the rbcL and trnL markers were more helpful to genus-level identification within Lamiaceae and Campanulaceae. These results enrich the DNA barcoding reference library and form a concrete contribution towards the protection, conservation and traceability of Crete's unique botanical heritage.