Introduction

Global economic growth and aviation industry expansion have accelerated the global spread of alien species, posing a serious threat to biodiversity conservation (Hulme, 2009; Spear et al., 2013). Owing to their high ecological adaptability, certain alien plants successfully establish populations in new environments and often outcompete native species, thereby altering community structures and destabilizing ecosystems (Diez et al., 2012). Numerous alien plants have been introduced in Korea, exerting both direct and indirect ecological impacts.

Coreopsis lanceolata is one of the most widely distributed alien plants in Korea. Its showy yellow flowers and extended flowering period have led to frequent use in landscaping by individuals, municipalities, and public institutions. However, naturalized populations outside of intentional planting sites have been increasingly observed (National Institute of Ecology, 2023). The National Institute of Ecology has classified C. lanceolata as a Level 2 invasive species due to its high potential for widespread expansion. Although the Ministry of Environment issued a recommendation against its planting, cultivation has continued nationwide, expanding its occupied area.

According to research conducted in China, C. lanceolata thrives in various disturbed sites, such as roadsides, farmland margins, and fallow lands, and its strong clonal growth confers high environmental adaptability (Zeng et al., 2012). In some regions, this species has already gained a competitive advantage over native plants, forming communities and exhibiting large-scale expansion.

In Japan, C. lanceolata competes with native riparian vegetation for light and space (Saito & Okubo, 2013). Owing to its ecological characteristics and invasive potential, C. lanceolata was designated as an Invasive Alien Species under the Invasive Alien Species Act in February 2006. Consequently, its cultivation, storage, transportation, and importation have been restricted, and the National Institute for Land and Infrastructure Management (2011), under the Ministry of Land, Infrastructure, Transport and Tourism, issued a removal and control manual.

In Korea, C. lanceolata is often confused with Coreopsis basalis, an annual herb native to North America, owing to their similar morphologies. However, their ecological traits differ markedly; while C. lanceolata is a perennial with a strong reproductive capacity and prolific seed production, which confer high invasive potential (Arifin & Okamoto, 2023; Folgate & Scheiner, 1992), C. basalis poses a relatively low ecological risk. Despite these differences, both species are distributed in Korea with the same label “Geumgyegook (C. basalis),” leading to frequent mislabeling and misplanting of C. lanceolata as C. basalis.

In this study, we aimed to identify the root causes of persistent coreopsis misidentification. To this end, we examined the taxonomic units used during the seed importation process and investigated commercial seed distribution records. In addition, we subjected seedlings grown from seeds marketed domestically as C. basalis to rbcL and matK sequence analyses and compared the results with reference sequences of C. basalis and C. lanceolata in the National Center for Biotechnology Information (NCBI) GenBank and National Institute of Biological Resources (NIBR) databases.

Through these approaches, we sought to elucidate the underlying factors driving the misidentification of C. lanceolata as C. basalis and provide scientific verification of species identity for seeds mislabeled and distributed as C. basalis in Korea.

Materials and Methods

To verify whether C. lanceolata was misidentified as C. basalis, we first examined the seed distribution records from the Korea Seed & Variety Service (KSVS). Using the “Production, Import, and Sales Notification of Varieties” function within the KSVS seed distribution-management system ( https://www.seed.go.kr/seed/index.do), we retrieved the declaration records for both species. This integrated national platform records all notifications related to the importation and production of horticultural, floricultural, crop, fruit, and genetically modified organism seeds. In the present study, we used these data to confirm the official distribution of C. basalis and C. lanceolata seeds.

For molecular verification, seeds labeled as C. basalis were purchased from ten different specialized seed vendors, all operating online. All purchased seed packages were labeled with the identical product name “Geumgyegook (C. basalis).” Germination was conducted in sterilized Petri dishes lined with sterile cotton that was moistened with distilled water. The dishes were evenly seeded and placed in a growth chamber under controlled conditions of 25°C, a constant relative humidity, and an 8 hours photoperiod. Young seedlings obtained 7-10 days after germination were used as the experimental material.

Genomic DNA was extracted from ten leaf samples using the Clear-S™ Quick DNA Extraction Kit (InvirusTech, Gwangju, Korea), following the manufacturer’s instructions. The extracted DNA (20 ng) was used as a template for polymerase chain reaction (PCR) amplification of rbcL and matK. The rbcL gene was amplified using the primers rbcL-F (5’-ATGTCACCACAAACAGAAAC-3’) and rbcL-R (5’-TCGCATGTACCYGCAGTTGC-3’). The PCR reactions were performed with a C1000 Touch™ Thermal Cycler (Bio-Rad, Hercules, CA, USA) under the following conditions: an initial denaturation at 95°C for 10 minutes, followed by 35 cycles of denaturation at 95°C for 30 seconds, annealing at 55°C for 30 seconds, and extension at 72°C for 1 minute, with a final extension at 72°C for 5 minutes. For matK amplification, we used the primers MatK-1RKIM-f (5’-ACCCAGTCCATCTGGAAATCTTGGTTC-3’) and MatK-3FKIM-r (5’-CGTACAGTACTTTTGTGTTTACGAG-3’) (Shaikhali et al., 2008) under similar conditions, with minor optimization as needed. The PCR products were confirmed through electrophoresis using 1.5% agarose gels and visualized under UV illumination. The amplified products were purified and subjected to Sanger sequencing (Bionics, Seoul, Korea).

The Consortium for the Barcode of Life Plant Working Group recommends rbcL and matK as standard DNA barcodes for plants (CBOL Plant Working Group, 2009); thus, both markers were analyzed in this study. However, rbcL, which evolves relatively slowly, was used primarily as a reference for cross-comparison with rbcL sequences of C. basalis and C. lanceolata available in the NCBI GenBank and NIBR databases. In contrast, matK, which exhibits higher variability, was used as the primary marker for species-level discrimination.

Sequence alignments were performed using the ClustalW algorithm in MEGA12 (Kumar et al., 2024). Phylogenetic analyses were conducted using the maximum likelihood method in MEGA12 by applying the general time-reversible substitution model. Rate heterogeneity was modeled using a discrete gamma distribution with five categories (+G), assuming no invariant sites (+I=0.00%). Gamma distribution parameters were set to 0.0479 for rbcL and 200.0000 for matK.

We analyzed 533 bp of rbcL (including codon positions 1, 2, and 3 along with non-coding regions) and 657 bp of matK sequences. Initial trees were generated from distance matrices using the neighbor-joining method (Saitou & Nei, 1987), and branch support was assessed using 1,000 bootstrap replications (Felsenstein, 1985).

Results and Discussion

Conclusion

This study provides scientific evidence that the persistent misidentification of C. lanceolata as C. basalis arises not from simple taxonomic errors but rather from systemic limitations in the regulatory framework. Because genus-level declarations are permitted at the import stage, C. lanceolata is erroneously distributed nationwide under the name C. basalis, thereby creating a major pathway for the spread of this alien species. Through DNA barcode analyses, we confirmed that commercial seeds sold as “Geumgyegook (C. basalis)” in Korea were in fact Chinese lineages of “Keungeumgyegook (C. lanceolata).”

Accordingly, we recommend the following measures:

1. Mandatory species-level verification and DNA barcode-based quarantine for seeds of alien plants designated as ecosystem-disturbing species, potentially harmful species, species under import alert, or species ranked at Level 2 or higher in ecological risk assessments.

2. Revision of the seed importation reporting system in coordination with the KSVS to ensure species-level accuracy for alien plant seeds.

3. Nationwide reassessment of Coreopsis spp. distribution to clarify the current extent of misidentified plantings.

These measures are essential not only for regulating the importation and distribution of alien plants but also for fundamentally improving Korea’s broader system of alien species management, thereby contributing to long-term ecological stability.