Cinnamyl alcohol dehydrogenase (CAD, EC 1.1.1.95), catalyzes the reduction of hydroxycinnamaldehydes to give hydroxycinnamyl alcohols, or "monolignols," the monomeric precursors of lignin. Lignins are important components of cell walls and lignified secondary cell walls play crucial roles in long distance transport of water and nutrients during plant growth and development and in plant defense against biotic and abiotic stresses. Here a cDNA clone containing a CAD gene, named as PgCAD, was isolated from a commercial medicinal plant Panax ginseng. PgCAD is predicted to encode a precursor protein of 177 amino acid residues, and its sequence shares high homology with a number of other plant CADS. The expression of PgCAD in adventitious roots and hairy roots of P. ginseng was analyzed using reverse transcriptase (RT)-PCR under various abiotic stresses such as salt, salicylic acid, wounding and chilling treatment that triggered a significant induction of PgCAD at different time points within 2-48 h post-treatment. This study revealed that PgCAD may help the plants to survive against various abiotic stresses.

Malate dehydrogenase is a ubiquitous enzyme in plants, involving in a range of metabolic processes depending on its subcellular location. A malate dehydrogenase (PgMDH) cDNA was isolated and characterized from the root of Panax ginseng C. A. Meyer. The deduced amino acid sequence of PgMDH showed high similarity with the NAD-dependent mitochondrial malate dehydrogenase from Glycinemax (P17783), Eucalyptus gunnii (P46487), and Lycopersicon esculentum (AAU29198). And the segment of a malate dehydrogenase gene was amplified through RT-PCR. The expression of PgMDH was increased after treatments of chilling, salt, UV, cadmium or copper treatment.

인삼의 생장에서 염류의 집적은 우량 인삼의 생산에 많은 장애요인이 되고 있다. 본 연구에서는 순계 분리된 인삼의 우수 계통으로부터 NaCl 처리에 따른 생장율 조사와 ginsenoside의 생산에 미치는 영향을 조사하였다. 선발된 모상근(KGHR-8)으로부터 ginsenosides의 함량에 미치는 NaCl의 최적 농도를 조사하기 위하여 30일간 배양한 결과 NaCl의 농도가 증가함에 따라 모상근의 생장은 감소하였지만, total ginsenoside의 함량은 0.24M NaCl 처리구에서 높은 증가를 가져왔으며 특히 광을 조사하여 배양한 결과 높게 검출되었다. 0.24 M NaCl 농도로 광상태하에서 함량은 61.7% 증가하는 양상을 나타내었다. (Table 1). 또한 모상근의 생장을 최적 상태로 설정하기 위해 two step culture 방법을 조사한 결과, 0.05M, 0.1M NaCl 처리시 모상근의 생장율은 각각 약 62%, 76% 감소한 반면, ginsenoside의 함량은 29%, 48% 각각 향상되었다. 모상근은 방어기작의 일환으로 NaCl을 elicitor로 인지하고 2차대사산물인 사포닌의 생산에 영향을 미치는 것으로 확인되었다.