The rapid conversion of Southeast Asian lowland rainforests into monocultures calls for the development of rapid methods for species identification to support ecological research and sustainable land‐use management. Here, we investigated the utilization of DNA barcodes for identifying flowering plants from Sumatra, Indonesia. A total of 1,207 matK barcodes (441 species) and 2,376 rbcL barcodes (750 species) were successfully 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 of monophyletic groups. Results show that rbcL has a much higher level of sequence recoverability than matK (95% and 66%). The comparison between morphological and molecular identifications revealed that matK and rbcL worked best assigning a plant specimen to the genus level. Estimates of identification success using best‐close match analysis showed that >70% of the investigated species were correctly identified when using single barcode. The use of two‐loci barcodes was able to increase the identification success up to 80%. The barcoding gap analysis revealed that neither matK nor rbcL succeeded to create a clear gap between the intraspecific and interspecific divergences. However, these two barcodes were able to discriminate at least 70% of the species from each other. Fifteen genera and twenty‐one species were found to be nonmonophyletic with both markers. The two‐loci barcodes were sufficient to reconstruct evolutionary relationships among the plant taxa in the study area that are congruent with the broadly accepted APG III phylogeny.

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Anacardiaceae is well-known for its edible fruits and economically important species in Indonesia. Approximately 3% of Indonesia's endangered and vulnerable species belong to this family. Fast and accurate species identification is crucial to support the conservation efforts for this family, such as employing DNA sequences. Species identification using DNA sequences, known as DNA barcoding, has been widely used in many applied fields. So far, the application of DNA barcoding for Anacardiaceae plant species is limited to several genera only, such as Mangifera and Spondias. This research aimed to enrich the DNA barcode references of Anacardiaceae and to evaluate the most suitable and effective genetic marker as DNA barcodes to identify species of 35 samples representing sixteen species of the Anacardiaceae family using chloroplast markers matK and rbcL as barcode regions. When comparing the morphological identification with the molecular assignments, the barcode accuracy was 62.50% (matK), 60.61% (rbcL), and 73.33% (matK+rbcL) at the genus level. All the markers failed to show a barcoding gap, even though the t-test showed that the intraspecific and interspecific genetic distances were significantly different for matK and rbcL+matK. Among others, Gluta walichii (Hook.f.) Ding Hou and Melanochyla caesia Jack were the only species successfully resolved by all markers. Nevertheless, new DNA barcodes of six Anacardiaceae species were made available by this study, enriching the genetic references of tropical flora diversity.

Fabaceae is an invaluable plant family with considerable ecological and economic importances for example as food sources, bio-fertilizer, and medicinal plants. However, Fabaceae has been overexploited in Indonesia and several species belong to this family are critically endangered. Due to morphological similarity, rapid and accurate identification of Fabaceae species is essential to support its conservation efforts. Nowadays, species identification through DNA barcoding has become an effective taxonomic classification tool. This study was aimed to evaluate the effectiveness of chloroplast markers, matK and rbcL and the combination (matK+rbcL), as DNA barcodes for the identification of seleted genera in Fabaceae. The result showed that matK+rbcL and matK had the highest level of identification (90% and 82.05%) of the investigated genera, respectively. Additionally, matK had the highest mean of interspesific distance (0.134) and intraspecific distance (0.003). The combined barcode matK+rbcL had the highest correct identification rate when comparing the morphological with molecular identification. Furthermore, the best phylogenetic tree was obtained using Neighbor Joining method. Based on the overall performance, matK and matK+rbcL were the best barcodes for the selected genera in this study.