[Analysis of expressed sequence tags (EST) from Panax quinquefolium root].

To investigate the profile of gene expression in American ginseng (Panax quinquefolium L.) and discover its functional genes, for the first time, expressed sequence tags (EST) library of four-year-old American ginseng roots has been established. According to BLAST and Gene Ontology analysis, eleven genes, encoding cytochrome P450, glucosyltransferase, farnesyltransferase and cyclase family protein, are found to be associated with ginsenosides biosynthesis. Six other genes are obtained encoding auxin-regulated protein, auxin response factor 4 and auxin-repressed protein in the roots of American ginseng. In addition, thirteen expressed transcripts are stress-connected proteins and twelve expressed other transcripts are closely related to plant defense in four-year-old American ginseng roots. Furthermore, 62 genes no hit in BLAST and in Interproscan may be new genes. These results indicate EST is an useful tool for research on functional genomics of P. quinquefolium and it can be applied to the molecular modification of the ginsenosides biosynthetic pathway ultimately for improving the quality of American ginseng germplasm.