The Korean Society of Ginseng 1 http://ginsengres.org pISSN: 1226-8453 eISSN: 2093-4947 Review J. Ginseng Res. Vol. 35, No. 1, 1-11 (2011) DOI:10.5142/jgr.2011.35.1.001 E-mail: dcyang@khu.ac.kr Tel: +82-31-201-2100, Fax: +82-31-202-2687 * Corresponding author INTRODUCTION Ginseng (Panax ginseng C. A. Meyer) is an important plant in East Asia, where nearly every species has been employed medicinally. In Chinese, ginseng literally means “man-herb,” which can be translated as “the essence of man.” In 1883, the genus Panax was added to the name, in which pan means “all” and axos means “cure.” Thus, the meaning of Panax ginseng is “all-healing man-herb” [1]. In China and Korea, the plant has been utilized for over 2,000 years as a tonic, a stimulant, and to foster stress-resistance [1]. The active constituents contained in most ginseng species include ginsenosides, polysaccharides, peptides, poly- acetylenic alcohols, and fatty acids [2]. Pharmaceutical- grade ginseng has been found to improve antibody- dependent cytotoxicity [3], ameliorate lung pathology [4], bolster learning in mice [5], potentiate vaccination against the common cold and influenza [6], inhibit the development of reverse tolerance to morphine [7], pre- vent free-radical damage to pulmonary vascular endothe- lium cells [8], exert anti-stress effects [9], inhibit muta- genesis [10], potentiate the generation of nerve fibers [11], and produce anti-aging effects [12]. The older is the ginseng plant, the greater is its medici- Defense Genes Induced by Pathogens and Abiotic Stresses in Panax ginseng C. A. Meyer Ok Ran Lee, Gayathri Sathiyaraj, Yu-Jin Kim, Jun-Gyo In, Woo-Seang Kwon, Ju-Han Kim, and Deok-Chun Yang * Korean Ginseng Center for Most Valuable Products & Ginseng Genetic Resource Bank, Kyung Hee University, Suwon 449-701, Korea Korean ginseng is a medicinally important perennial herb from the family Araliaceae. It has been cultivated for its highly valued medicinal properties for over 1,000 years in east Asian countries such as China, Korea, and Japan. Due to its longtime cultivation in shady areas, ginseng is frequently exposed to pathogenic infections. Plants protect themselves from microbial pathogens using an array of defense mechanisms, some of which are constitutively active, while others are activated upon pathogen invasion. These induced defense responses, controlled by defense-related genes, require tradeoffs in terms of plant fitness. We hypothesize that ginseng, as with other plants, possesses regulatory mechanisms that coordinate the activation of attacker-specific defenses in order to minimize fitness costs while attaining optimal resis- tance. Several classes of defense-related genes are induced by infection, wounds, irradiation, and other abiotic stresses. Both salicylates and jasmonates have been shown to cause such responses, although their specific roles and interactions in signaling and development are not fully understood in ginseng. This review summarizes possible defense-related genes in ginseng based on their expression patterns against biotic and abiotic stresses and describes their functional roles. Keywords: Panax ginseng, Ginseng, Pathogens, Pathogenesis-related, Jasmonic acid, Defense-responsive gene This is an Open Access article distributed under the terms of the Cre- ative Commons Attribution Non-Commercial License (http://creativecom- mons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Received 16 Aug. 2010, Revised 21 Oct. 2010, Accepted 1 Nov. 2010