XVI International Botanical Congess

To investigate the mechanism of plant responses to pathogen attack and environmental stresses, we established adventitious root cultures of the model legume _Lotus japonicus_. The accumulation of an isoflavan vestitol was observed in the cultures elicited with glutathione (reduced form). The degenerate PCR using oligonucleotide primers based on the conserved amino acid sequences yielded several cDNA fragments that show high similarity to flavonoid pathway-related genes. We further obtained full-length cDNAs involved specifically in the biosynthesis of isoflavonoid-derived phytoalexins, i.e. 2-hydroxyisoflavanone synthase, isoflavone 2'-hydroxylase, and isoflavone reductase, some of which were functionally expressed in heterologous systems. The effect of elicitor treatment on their expression will be reported.