Overexpressing Arabidopsis jasmonic acid carboxyl methyltransferase (AtJMT) results in stimulation of root growth and ginsenoside heterogeneity in Panax ginseng

초록

Methyl jasmonate (MeJA) triggers the production of secondary metabolites in plants and participates in a diverse range of plant developmental processes. MeJA is derived from jasmonic acid (JA) via the octadecanoid pathway and the reaction is catalyzed by jasmonic acid carboxyl methyltransferase (JMT). In this study, transgenic Panax ginseng roots were constructed to express an Arabidopsis jasmonic acid carboxyl methyltransferase (AtJMT). The transgenic lines exhibited high expression of genes (PgSS1, PgSE1, and PgDDS) involved in ginsenoside biosynthetic pathways as well as a MeJA-responsive gene (PgPR10-2). These alterations of the gene expressions led to 3-fold increase in the growth of transgenic roots. Overexpression of AtJMT gene strongly affected the ginsenoside heterogeneity (protopanaxadiol/protopanaxatriol ratio) although total ginsenoside accumulation was slightly increased in transgenic roots. Protopanaxadiol group of ginsenosides (Rb1, Rc, and Rb2) increased about 2-fold in transgenic roots compared to those in wild-type. The results suggest that overexpression of AtJMT stimulate not only the growth of roots but also the production of protopanaxadiol-group in transgenic roots.

키워드