Background : Cytochrome P450 enzymes belong to the superfamily of monooxygenases that are found in all living organisms with diversity in their reaction chemistry. These P450 enzymes are being used extensively by plants in their defense mechanism. Tetracyclic triterpenes reported as major ginsenoside constituents in Panax ginseng, formed by multiple hydroxylation of cytochrome P450. CYP P450 enzymes is effective in metabolising both natural and xenobiotic compounds. In this study, two ginseng CYP genes (PgCYP76C and PgCYP736A) were functionally characterized by overexpression in heterologous plant system. Methods and Results : In Arabidopsis thaliana and Panax ginseng, planta transformation was generated by floral and cotyledon dipping method using Agrobacterium tumefaciens (C58C1) individually. Spatial and temporal patterns of gene expression were analyzed by qRT-PCR against abiotic and biotic stresses. Herbicide (chlorotoluron) tolerance was performed at seedling stage by in vitro assay to check ectopic expressions. PgCYP736A expression were more abundant in leaves compared to roots and stem of 2-years-old ginseng, where as PgCYP76C gene was found to be highly expressive in rhizome, roots and leaves. Differential expressions were observed in response to abiotic stresses of two ginseng CYP genes, both expressed higher in response to NaCl and SA (salysilic acid) in ginseng. Transgenic Arabidopsis plants overexpressing PgCYP76C gene showed small, rounded leaves and reduced height. This phenotype was found to be caused by down regulation of gibberellin biosynthesis-related genes. Another function revealed tolerance towards herbicides that belongs to phenyl urea. Conclusion : This study indicates the functional roles of CYP genes in plant growth and stress responses. Studied genes also can be used as a tool to make plants herbicide tolerant. Further investigation might focus on it’s function over terpene biosynthesis and defence mechansim against (a)biotic stress.

Background : Ginseng seeds are harvested in immature stages and take 3 - 4 month to be germinated following cold stratification. Improvement of germination speed can be a valuable traits to be characterized for economically important medicinal plant. Modulation of cell wall compositions is also considered as another agricultural trait when the crops can be processed for foods and forages. Here we show the functional characterization of ginseng pPLAIIIβ focused on its possible values on germination and modulation of cell wall compositions. Methods and Results : Patatin-related phospholipase AIII family genes were identified from ginseng EST clones and further confirmed by PCR. Clone showing the highest homology with pPLAIIIβ was overexpressed in model plant Arabidopsis, and it displayed dwarf plants. qPCR analysis showed that pPLAIIIβ expressed in all organs of 2-years-old ginseng. Overexpression of ginseng pPLAIIIβ also displayed apparently enlarged seeds as well as altered germination speed in early stage compared to the control. Chemical stainings and direct quantification of lignin and cellulose were performed to understand the link of cell elongation patterns and cell wall compositions. Conclusion : Overexpression of ginseng pPLAIIIβ inhibited longitudinal cell elongation in all tested organs except seeds which is enlarged in both directions than the control. Shorter root length is related with auxin responsive genes and its dwarf morphological phenotype is resulted in altered cell wall compositions.

Background: The demand of recycling renewable agricultural by-products is increasing. Radiation breeding is a method used to improve saccharification efficiency. Thus, we investigated the effect of gamma ray irradiation on the pretreatment and enzymatic hydrolysis of the stalks of Senna tora, an important medicinal plants. Methods and Results: S. tora seeds were irradiated with gamma ray at doses of 100, 200, 300, and 400 Gy. In the pretreated biomass, glucan and lignin content were higher in the M1 (1st generations of irradiation) S. tora stalks than in the M2 (2nd generations of irradiation) stalks, this can be explained by the higher degradation rate in M1. After oxalic acid pretreatment, the concentration of total phenolic compounds (TPCs) in the hydrolysate increased in the gamma ray treated seeds. The highest relative increase rate in crystallinity in the pretreated biomass was observed in M1-400 Gy and M2-100 Gy. The cellulose conversion rate was higher in M1 than in M2, except for 200 Gy. Conclusions: Gamma ray irradiation at an appropriate dose can be used to improve the efficiency of pretreatment and enzymatic hydrolysis, thereby increasing biomass availability.

Background: Senna tora is a flowering plant in the legume family Fabaceae. Its seeds are roasted and consumed as tea in Asia, to reduce inflammation in the liver and improve eyesight. Thus, it has been considered as an important medicinal crops in Asia. However, breeding trials to improve its genetic properties are rare. Mutation breeding by gamma ray is known to be an effective and highly successful approach for the generation of agronomically useful cultivars. Here we analyzed the effects of several dosages of gamma ray on the biological conditions of Senna tora seeds. Methods and Results: The germination rate and growth patterns of Senna tora were examined following irradiation with gamma ray at 100, 200, 300 and 400 Gy. The total phenolic compound contents and antioxidant activities of Senna tora were analyzed. Germination increased at 100 and 200 Gy in the M1 and M2 generations compared with that of the control (M0). The total phenolic compound contents and antioxidant activity of the seeds significantly decreased as the radiation dosage increased above 100 Gy in the M1 generation. Conclusions: Senna tora, irradiated with gamma ray at dosages 100, 200, 300, and 400 Gy, showed maximum germination rate at 200 Gy in the M2 generation. Plant height and leaf size gradually decreased with increasing gamma ray intensity in the M2 generation. The total phenolic compound contents decreased significantly at 400 Gy, and the related antioxidant activity was also decreased as the radiation dosage increased.

Background : Both Panax ginseng Meyer and Panax quinquefolius are obligate shade-loving plants whose natural habitats are broadleaved forests of Eastern Asia and North America. Panax species are easily damaged by photoinhibition when they are exposed to high temperatures or insufficient shade. In this study, a cytohistological study of the leaf structures of two of the most well-known Panax species was performed to better understand the physiological processes that limit photosynthesis. Leaves of ginseng plants grown in soil and hydroponic culture were sectioned for analysis. Methods and Results : Leaf structures of both Panax species were observed using a light microscope, scanning electron microscope, and transmission electron microscope. The mesostructure of both P. ginseng and P. quinquefolius frequently had one layer of noncylindrical palisade cells and three or four layers of spongy parenchymal cells. P. quinquefolius contained a similar number of stomata in the abaxial leaf surface but more tightly appressed enlarged grana stacks than P. ginseng. The adaxial surface of the epidermis in P. quinquefolius showed cuticle ridges with a pattern similar to that of P. ginseng. Conclusion : The anatomical leaf structure of both P. ginseng and P. quinquefolius shows that they are typical shade-loving sciophytes. Slight differences in chloroplast structure suggests that the two different species can be authenticated using transmission electron microscopy images, and light-resistant cultivar breeding can be performed via controlling photosynthesis efficiency.

Background : Prenyltransferases catalyze the sequential addition of IPP units to allylic prenyl diphosphate acceptors and are classified as either trans-prenyltransferases (TPTs) or cis-prenyltransferases (CPTs). Although CPTs and TPTs share similar substrate preferences and reaction products, they can be easily distinguished by their primary amino acid sequences. The characterization of cis-prenyltransferases has been less studied than that of trans-prenyltransferases. Methods and Results : Gene expression patterns of PgCPT1 was analyzed by qRT-PCR. In planta transformation was generated by floral dipping using Agrobacterium tumefaciens. Yeast transformation was performed by lithium acetate and heat-shock for rer2Δ complementation and yeast-two-hybrid assay. Ginseng genome contains at least one family of three putative CPT genes. PgCPT1 is expressed in all organs, but more predominantly in the leaves. Overexpression of PgCPT1 did not show any plant growth defect, and can complement yeast mutant rer2Δ via possible protein-protein interaction with PgCPTL2. Conclusion : Partial complementation of the yeast dolichol biosynthesis mutant rer2Δ suggested that PgCPT1 is involved in some of dolichol biosynthesis. Direct protein interaction between PgCPT1 and a human Nogo-B receptor homolog suggests that PgCPT1 requires an accessory component for proper function.

Background : Glycosylation of natural compounds results in great diversity of secondary metabolites. Glycosylation steps are implicated not only in plants growth and development but also in plant defense responses to various environmental stresses. This process is mediated by members of a multigene superfamily glycosyltransferase (GT), which catalyze the transfer of single or multiple activated sugars to a wide range of substrates, thus influences their chemical property and bioactivity. Although its activity has been recognized for a long time and genes coding UGTs in several higher plants have been identified, specific function of GTs in detail still remains elusive. Methods and Results : Spatial and temporal expression patterns of a ginseng UDP-dependent glycosyltransferase, was analyzed by qRT-PCR. It was expressed highly in rhizome, upper root and youngest leaf compared that of other organs. Spacial expression was observed by GUS histochemical assay after generating promoter::GUS fusion. Noticeably, it expressed axillary branch as well as other organs tested by qRT-PCR. Overexpression of PgUGT in Arabidopsis resulted in fused organ in axillary branch. Stress responsiveness against various abiotic stresses and subcellular localization in Arabidopsis are also addressed. Conclusion : PgUGT phylogenetically closed to PgUGT71A27 involved in ginsenoside compound K (C-K) production. Considering that the C-K is not reported in raw ginseng material, further characterization of this gene may shed light on the biological function of C-K in ginseng growth and development. Organ fusion phenotype could be caused by defective growth of cells in boundary region, commonly regulated by phytohormones such as auxins or brassinosteroids, which in needs to be analyzed further.

This study was carried out to investigate the effect of sucrose, boric acid, and calcium nitrate in optimum pH and relative humidity on pollen germination and pollen tube growth of boxthorn (Lycium chinense M.). Medium containing 100mg/L of H3BO3 showed maximum pollen germination and pollen tube elongation, 64.8% and 920μm. Additionally supplied calcium nitrate to the medium lowered pollen germination rate and pollen tube elongation. Here we report the optimum conditions for the pollen germination and pollen tube development was observed at 10% sucrose, 1.0% agar, pH 6.0, and 100% relative humidity.