Effectiveness, Sequence Characterization, And DNA QR Code of Internal Transcribed Spacer 1 (ITS1) in Identification of Scopellaria Marginata (Cucurbitaceae)

Species identification accurately is crucial in plant sciences. DNA barcoding, which is an accurate approach for molecular identification that involves the use of short and standardized regions such as internal transcribed spacer (ITS1). To date, the availability of barcode sequences for Scopellaria marginata (Cucurbitaceae) is still very limited in public databases including ITS1. The purpose of this study was to investigate the effectiveness, to characterize, and to develop the DNA QR code of ITS1 sequences in the identification of Scopellaria marginata. The DNA barcoding was carried out by DNA extraction from three individual S. marginata, DNA amplification with one pair barcode primer of ITS1, and bi-directional DNA sequencing using the Sanger’s method. Nucleotide composition, phylogenetic tree construction, correct assignment rate (CAR), and DNA QR code were evaluated. The results showed that the ITS1 region in S. marginata with the size of ~290 bp comprises nucleotide composition A, T, G, C, G+C, and A+T content of 23.0%, 17.7%, 26.3%, 33.1%, 59.3%, and 40.7%, respectively. The homology analysis using BLAST and phylogenetic tree reconstruction showed that all samples were identified as S. marginata. The effectiveness of ITS1 as a DNA barcode in the identification of S. marginata showed 100% as the correct assignment rate value. A region of 218 bp was proposed as a specific DNA barcode for S. marginata and also converted as a DNA QR code. Therefore, the ITS1 was shown as an effective barcode for the identification of S. marginata.