Development of molecular markers for the determination of the new cultivar 'Chunpoong' in Panax ginseng C. A. Meyer associated with a major latex-like protein gene.

Chunpoong is one of the most valuable cultivars of Panax ginseng C. A. MEYER, and is widely grown in Korea and China. Insertion/deletion (InDel) markers and single nucleotide polymorphism (SNP) markers are useful tools for marker-assisted selections. The SNP marker for determinate Chunpoong was previously developed from the nad7 gene of mtDNA by Wang et al. (2009) but was effective only on a limited range of cultivars. In this study, we studied the reasons for this limited application and developed new useful markers for application in Chunpoong-breeding programs. The new markers of InDel and SNP were designed in the major latex-like protein (MLP-like) gene which was highly expressed in 4-year-old Chunpoong expressed sequence tags (ESTs). To validate the marker in polymerase chain reaction (PCR), we used an InDel marker for identification of Chunpoong in the 70 Panax samples based on a double-blind test, and the success rate was 100%. For rapid and reliable assay of Chunpoong in numerous samples, we utilized an EvaGreen dye and melting curve method on real-time PCR. Furthermore, we designed an SNP marker that depended on the InDel region for more efficient detection of Chunpoong in real-time PCR. Compared with PCR-based assays, our Chunpoong SNP marker and real-time PCR assay offers a significant savings of time and labor in the analysis of large numbers of Chunpoong samples.