Abstract
Aim and Background: The marigold plant species is renowned for its therapeutic properties and diverse health benefits. Recently, researchers have explored the potential of utilizing marigold plants as hyperaccumulators to extract heavy metals from polluted soil and water. However, ensuring accurate species identification is essential for this purpose. This study focuses on evaluating the efficacy of rbcL and matK markers for DNA barcoding and species identification in marigold plants.
Methods: Plant material from Tagetes erecta, Tagetes patula, and Calendula officinalis was collected, and DNA extraction was performed using a modified CTAB technique. Qualitative and quantitative analyses of the extracted DNA were conducted using NanoDrop and agarose gel electrophoresis. PCR amplification of the rbcL and matK genes was successful, yielding distinct bands on agarose gel. Sequencing of PCR products and subsequent analysis confirmed the identity of marigold species.
Results: Nucleotide BLAST analysis revealed high identity scores for rbcL sequences, indicating its potential as a DNA barcode for marigold species. However, matK showed limitations in species discrimination due to lower annealing temperatures. Combining rbcL and matK improved species discrimination and identification accuracy. Comparison with previous studies supported the efficacy of rbcL and matK in DNA barcoding across various plant groups.
Conclusion: The study suggests that rbcL is a promising marker for robust identification of marigold species, with implications for biodiversity studies, conservation, and medicinal plant authentication. Further research into additional genetic markers and optimization of DNA barcoding protocols could enhance the accuracy and reliability of species identification in marigold plants and other taxa.

Key words: DNA barcoding, Marigold, rbcl, matK Tagetes erecta, Tagetes patula, calendula officinalis