Tae-Woong Bae

Ginsenoside Production and Morphological Characterization of Wild Ginseng (Panax ginseng Meyer) Mutant Lines Induced by γ-irradiation ( 60 Co) of Adventitious Roots

With the purpose of improving ginsenoside content in adventitious root cultures of Korean wild ginseng (Panax ginseng Meyer), the roots were treated with different dosages of γ-ray (5, 10, 25, 50, 75, 100, and 200 Gy). The growth of adventitious roots was inhibited at over 100 Gy. The irradiated adventitious roots showed significant variation in the morphological parameters and crude saponin content at 50 to100 Gy. Therefore, four mutant cell lines out of the propagation of 35 cell lines treated with 50 Gy and 100 Gy were selected on the basis of phenotypic morphology and crude saponin contents relative to the wild type control. The contents of 7 major ginsenosides (Rg1, Re, Rb1, Rb2, Rc, Rf, and Rd) were determined for cell lines 1 and 3 from 100 Gy and lines 2 and 4 from 50 Gy treatments. Cell line 2 showed more secondary roots, longer length and superior growth rate than the root controls in flasks and bioreactors. Cell line 1 showed larger average diameter and the growth rate in the bioreactor was comparable with that of the control but greater in the flask cultured roots. Cell lines 1 and 2, especially the former, showed much more ginsenoside contents than the control in flasks and bioreactors. Therefore, we chose cell line 1 for further study of ginsenoside contents. The crude saponin content of line 1 in flask and bioreactor cultures increased by 1.4 and 1.8-fold, respectively, compared to the control. Total contents of 7 ginsenoside types (Rg1, Re, Rb1, Rb2, Rc, Rf, and Rd) increased by 1.8 and 2.3-fold, respectively compared to the control. Crude saponin and ginsenoside contents in the bioreactor culture increased by about 1.4-fold compared to that the flask culture.

Recent developments in biotechnological improvement of Zoysia japonica Steud.

Abstract Zoysiagrass ( Zoysia japonica Steud.), also called Korean or Japanese lawngrass, is the most popular warm- season turfgrass in Korea and is widely used for home lawns, parks, roadsides, golf courses and athletic fields. Its use is rapidly expanding in Korea and the other countries, due to its excellent characteristics which include tolerance to heat, drought and salinity. As the utilization area of this turfgrass increases, there is an increase in the demand for improved cultivars with disease and insect tolerance or with herbicide- tolerance or with extended greening periods. Conventional breeding methods have been used to improve the traits de-scribed above with limited success. However, with the advances in biotechnology, genetic transformation can be utilized for turfgrass improvement. In this paper, we review recent progress in biotechnological improvement of zoysiagrass and discuss future molecular breeding of this species. 서 론 들잔디 ( Zoysia japonica Steud.)는 한국을 포함한 극동아시아와 대부분의 온대지역에 분포하는 난지형 잔디 중의 하나로 초장이 짧아서 예초에 강하고 열, 가뭄 및 염분에 대해 내성이 뛰어나며 일반적으로 병충해에 강한 잔디이다. 그러나 몇몇 병충해에 대해서는 민감한 반응을 보이며 기온이 10℃ 이하가 되면 휴면에 들어가 지상부가 고사하여 녹색 유지기간이 한지형 잔디에 비해 짧고 음지에서 잘 자라지 못하는 단점이 있다 (Inokuma et al. 1996; Lee et al. 2004). 잔디는 경관보호, 토양 및 수자원 보호, 신변보호 등 여러 가지 목적으로 활용되고 있으며, 도로, 하천, 비행장의 토양침식 방지에서부터 주택, 공원, 정원, 골프장, 스포츠 경기장 등으로 그 이용범위가 나날이 확대되고 있다. 이로 인한 잔디의 급격한 수요 증가와 더불어 잔디관련 사업규모가 크게 확대되고 있어 병해충 저항성, 내한성, 제초제 저항성, 내음지성, 녹기 연장 등 다양한 형질을 가진 잔디품종의 개발이 요구되고 있다. 지금까지 들잔디의 품종육성은 전통적인 육종방법을 이용하고 있으나 타 작물의 경우와 마찬가지로 고전육종기술의 한계점들이 발견됨에 따라 최근에는 분자생물학적 방법을 이용한 신품종 개발이 시도되고 있다 (Inokuma et al. 1998; Rim et al. 2001; Kim et al. 2004; Zhang et al. 2007). 분자생물학적 방법을 이용한 들잔디의 신품종 개발을 위해서는 먼저 조직배양과 형질전환체계가 확립되어야 한다. 들잔디의 조직배양에 관한 연구는 원형질체로부터 식물체 재분화 (Asano 1989; Inokuma et al. 1996), 미성숙종자의 미숙배에서 유도한 캘러스로부터의 식물체 재분화 (Park et al. 1994; Noh et al. 1995; Park and Ahn 1998), 성숙종자 유래 캘러스로부터의 식물체 재분화 (Al-Khayri et al. 1989; Rim et al. 2001; Bae et al. 2001; Lee et al. 2004) 등이 보고 된 바 있다. 그러나 원형질체를 이용한 조직배양은 분리나 배양에 어려움이 있고 미성숙종자를 이용한 조직배양은 재료의 지속적인 확보가 어려워 그 활용이 크게 제한적이어서 최근의 들잔디 조직배양에 관한 연구에는 주로 성숙종자 유래의 캘러스가 이용되고 있다 (Liu et al. 2009; Song et al. 2010). 들잔디의 형질전환에 관한

Environmental risk assessment of genetically modified Herbicide-Tolerant zoysiagrass (Event: Jeju Green21)

Abstract Transgenic zoysiagrass ( Zoysia japonica Steud.) expressing the bar gene inserted in the plant genome has been generated previously through Agrobacterium tumefaciens - mediated transformation. The GM zoysiagrass (event: JG21) permits efficient management of weed control of widely cultivated zoysiagrass fields, reducing the frequency and cost of using various herbicides for weed control. Now we have carried out the environmental risk assessment of JG21 prior to applying to the governmental regulatory agency for the commercial release of the GM turf grass outside of test plots. The morphological phenotypes, molecular analysis, weediness and gene flow from each test plot of JG21 and wild-type zoysiagrasses have been evaluated by selectively analyzing environmental effects. There were no marked differences in morphological phenotypes between JG21 and wild-type grasses. The JG21 retained its stable integration in the host plant in T 1 generation, exhibiting a 3:1 segregation ratio according to the Mendelian genetics. We confirmed the copy number (1) of JG21 by using Southern blot analysis, as the transgenic plants were tolerant to ammonium glufosinate throughout the culture period. From cross-fertilization and gene flow studies, we found a 9% cross-pollination rate at the center of JG21 field and 0% at distances over 3 m from the field. The JG21 and wild-type zoysiagrass plants are not considered “weed” because zoysiagrasses generally are not dominant and do not spread into weedy areas easily. We assessed the horizontal gene transfer (HGT) of the transgene DNA to soil microorganisms from JG21 and wild-type plants. The bar gene was not detected from the total genomic DNA extracted from each rhizosphere soil of GM and non-GM Zoysia grass fields. Through the monitoring of JG21 transgene’s unintentional release into the environment, we found no evidence for either pollen mediated gene flow of zoysiagrass or seed dispersal from the test field within a 3 km radius of the natural habitat.

Plant regeneration of Korean wild ginseng (Panax ginseng Meyer) mutant lines induced by γ-irradiation (60Co) of adventitious roots

An efficient in vitro protocol has been established for somatic embryogenesis and plantlet conversion of Korean wild ginseng (Panax ginseng Meyer). Wild-type and mutant adventitious roots derived from the ginseng produced calluses on Murashige and Skoog (MS) medium supplemented with 0.5 mg/L 2,4-dichlorophenoxyacetic acid and 0.3 mg/L kinetin; 53.3% of the explants formed callus. Embryogenic callus proliferation and somatic embryo induction occurred on MS medium containing 0.5 mg/L 2,4-dichlorophenoxyacetic acid. The induced somatic embryos further developed to maturity on MS medium with 5 mg/L gibberellic acid, and 85% of them germinated. The germinated embryos were developed to shoots and elongated on MS medium with 5 mg/L gibberellic acid. The shoots developed into plants with well-developed taproots on one-third strength Schenk and Hildebrandt basal medium supplemented with 0.25 mg/L 1-naphthaleneacetic acid. When the plants were transferred to soil, about 30% of the regenerated plants developed into normal plants.