Identification and analysis of differentially expressed genes in mountain cultivated ginseng and mountain wild ginseng.

Ginseng is one of the most widely used herbal medicines in the world. Wild ginseng is thought to be more effective than cultivated ginseng in chemoprevention; however, little has been reported on the differences between wild and cultivated ginseng. In the present study we used suppressive subtractive hybridization to identify wild ginseng-specific genes. One of the clones isolated in this screen was the NRT2 gene (designated pNRT2), a high-affinity nitrate transporter. Real-time reverse transcription-polymerase chain reaction results showed that pNRT2 expression was significantly upregulated in wild ginseng compared with cultivated ginseng. However, pNRT2 mRNA levels were similar between mountain cultivated ginseng and mountain wild ginseng. Nitrate is an important nitrogen source for plant growth, and its soil levels can vary in wild environments; thus it is conceivable that pNRT2 expression is upregulated in wild ginseng and may be an important marker of wild ginseng.