DNA barcoding of flowering plants in Sumatra, Indonesia

The rapid conversion of Southeast Asian lowland rainforests into monocultures callsfor the development of rapid methods for species identification to support ecologicalresearch and sustainable land‐use management. Here, we investigated the utilizationof DNA barcodes for identifying flowering plants from Sumatra, Indonesia. A total of1,207 matK barcodes (441 species) and 2,376 rbcL barcodes (750 species) were suc‐cessfully generated. The barcode effectiveness is assessed using four approaches: (a)comparison between morphological and molecular identification results, (b) best‐close match analysis with TaxonDNA, (c) barcoding gap analysis, and (d) formation ofmonophyletic groups. Results show that rbcL has a much higher level of sequencerecoverability than matK (95% and 66%). The comparison between morphologicaland molecular identifications revealed that matK and rbcL worked best assigning aplant specimen to the genus level. Estimates of identification success using best‐close match analysis showed that >70% of the investigated species were correctlyidentified when using single barcode. The use of two‐loci barcodes was able to in‐crease the identification success up to 80%. The barcoding gap analysis revealed thatneither matK nor rbcL succeeded to create a clear gap between the intraspecific andinterspecific divergences. However, these two barcodes were able to discriminate atleast 70% of the species from each other. Fifteen genera and twenty‐one specieswere found to be nonmonophyletic with both markers. The two‐loci barcodes weresufficient to reconstruct evolutionary relationships among the plant taxa in the studyarea that are congruent with the broadly accepted APG III phylogeny.