A universal DNA-barcode approach to aid species identification in the family Cyperaceae

Cyperaceae, one of the ten largest plant families with a cosmopolitan distribution, presents significant taxonomic challenges due to its highly reduced and complex floral structures. These complexities make species identification through conventional morphology-based methods difficult. To address these limitations, DNA barcoding was employed for accurate species identification. This study evaluates the universality of DNA barcodes across the entire Cyperaceae family using a total of 6739 sequences. The performance of four DNA barcoding regions ITS, matK, rbcL, and rps16, was explored using three analytical approaches, genetic distance, sequence similarity, and phylogenetic tree methods. Among single-locus barcodes, the nuclear region internal transcribed spacer (ITS) showed higher discriminatory power than the chloroplast regions matK, rbcL, and rps16. Among multi-locus combinations, ITS + matK + rps16 was found to be most effective. These findings provide valuable insights for improving the precise identification of Cyperaceae species. Future efforts should focus on sampling species-rich tribes such as Cariceae, Cypereae, Schoeneae, Rhynchosporeae, and Sclerieae, particularly in poorly sampled regions of Asia and Africa. Expanding these efforts is crucial for building a robust and comprehensive GenBank reference database for Cyperaceae.