Iron availability alters ascorbate-induced stress metabolism in Glehnia littoralis root cultures

Our previous study indicated that formation of furanocoumarin phytoalexins could be induced in Glehnia littoralis root cultures by treatment with 10–40 mM ascorbic acid (AsA). This furanocoumarin production is much less evident when G. littoralis roots are treated with AsA under iron-deficient conditions. Instead, two large unknown peaks appeared in the HPLC chromatogram, whose chemical structures were elucidated by spectroscopic methods as being 6, β-dihydroxyphenethyl ferulate (DF) and 6-hydroxyphenethyl ferulate (HF), respectively. Their maximal level of induction was observed at 20 mM AsA, and the production of DF always exceeded that of HF. This is the first report of these compounds in G. littoralis and of the modulation of the phytoalexin biosynthetic pathway in G. littoralis by iron deficiency.