Panax ginseng C.A. Meyer, commonly known as Korean or Asian ginseng, is a perennial herb which is native to Korea and China. Its roots are highly prized for several medicinal properties. Therefore, Ginseng has been a top-ranked subject of many fields of scientific research worldwide. However, very limited number of research work has been published on species authentication using DNA marker system. In this study, 22 simple sequence repeat (SSR) markers were used to analyze the genetic diversity and population structure of 167 ginseng cultivars from 11 regions and 10 breed varieties. A total number of 111 alleles were detected, with an average of 5.05 per locus. The average expected heterozygosity and polymorphism information content (PIC) for SSR locus were 0.35 and 0.30, respectively. The model-based structure analysis revealed that 66.5% of all cultivars could be grouped into three populations with inferred value (allele shared >70%) membership. More than 33% of tested cultivars derived from two ancestries, which was basically consistent with clustering based on genetic distance. Almost all of the cultivars shared the ancestry with S1 and S2 except 1 China Jilin and 3 USA cultivars. The result indicated that most of Korean ginsengs are closely interrelated between the two ancestors but USA ginsengs are totally different from Asian cultivars.

Objectives Here, we report the effect of overexpression of ginseng farnesyl diphosphate synthase on the transcription of three key regulatory enzymes involved in triterpene metabolism in hairy root of ginseng and Centella asiatica (L.) Urban. Materials and Methods A four-year-old root of Panax ginseng C.A. Meyer and Centella asiatica (L.) Urban whole plants were obtained from National Institute of Crop Science (Suwon, Korea) and Chonnam National University (Gwangju, Korea), respectively. Agrobacterium rhizogenes R1000 strain was kindly provided by Dr. In (Nongwoo Bio, Yeju, Korea). Results and Discussion The role of farnesyl diphosphate synthase (FPS) in triterpene biosynthesis (Fig. 1) was investigated. A pCAMBIA3101 vector was used to insert a exogenous gene into target plant genome (Fig. 2). After the transformation, we produced Panax ginseng and Centella asiatica hairy roots by introducing the coding region of the gene from Panax ginseng. In these hairy roots, integration of the transgenes into the C. asiatica nuclear genome was confirmed by PCR analysis using PgFPS (P. ginseng FPS) primers and by Southern hybridization using PgFPS-specific probe. FPS specific activity is increased 4-fold compared to controls. In RT-PCR analysis, overexpression of PgFPS in hairy roots was observed (Fig. 3) and two genes, cycloartenol and beta-amyrin synthase, related to triterpene biosynthesis were up-regulated. These results suggest that FPS overexpression might lead to an enhanced biosynthesis of triterpene saponins and phytosterols. However, we did not demonstrate whether or not the introduction of PgFPS gene in Centella asiatica genome directly enhances triterpene saponin production, although our results showed that gene expression related to triterpene saponin biosynthesis were obviously up-regulated. Therefore, additional experiments such as overexpression of FPS gene in triterpene saponin-deficient mutant plants will be required.

Sequence-tagged site (STS) markers tightly linked to the bacterial leaf blight (BLB) resistance genes, xa5, xa13 and Xa21, were used in this study. A survey was conducted to find polymorphisms between the resistant and susceptible germplasm in rice. 500 of Korean varieties and 100 of landraces were evaluated in this study. STS marker, RG207 was used to having xa5 resistance gene of rice germplasm. 27 varieties of Korean germplasm showed resistant for xa5 gene. The RG136 an xa-13 marker resulted in a single band of approximately 1kb in all the rice accessions studied. In order to detect polymorphism, digestion of the polymerase chain reaction (PCR) product was performed using a restriction enzyme Hinf Ⅰ. The resistant lines resulted in two bands 0.5kb on digestion with Hinf Ⅰ, while the same enzyme did not digest the PCR product of susceptible lines. No polymorphism was detected in Korean varieties and landraces, indicating that they probably do not contain xa13 gene. pTA248 an Xa-21 marker detected a band of 1kb in the resistant lines and bands of either 750bp or 700bp in the susceptible lines. Among germplasm tested, there are no varieties and landraces with Xa21 resistant gene. The results of the germplasm survey will be useful for the selection of parents in breeding programs aimed at transferring these bacterial blight resistance genes from one varietal background to another.