Enhancement of Glucosinolate Production in Watercress (Nasturtium officinale) Hairy Roots by Overexpressing Cabbage Transcription Factors

Glucosinolates are secondary metabolites that play important roles in plant defense and human health, as their production in plants is enhanced by overexpressing transcription factors. Here, four cabbage transcription factors (IQD1–1, IQD1–2, MYB29–1, and MYB29–2) affecting genes in both aliphatic and indolic glucosinolates biosynthetic pathways and increasing glucosinolates accumulation were overexpressed in watercress. Five IQD1–1, six IQD1–2, five MYB29–1, six MYB29–2, and one GUS hairy root lines were created. The expression of all genes involved in glucosinolates biosynthesis was higher in transgenic lines than in the GUS hairy root line, in agreement with total glucosinolates contents, determined by high-performance liquid chromatography. In transgenic IQD1–1 (1), IQD1–2 (4), MYB29–1 (2), and MYB29–2 (1) hairy root lines, total glucosinolates were 3.39-, 3.04-, 2.58-, and 4.69-fold higher than those in the GUS hairy root lines, respectively. These results suggest a central regulatory function for IQD1–1, IQD1–2, MYB29–1, and MYB29–2 transcription factors in glucosinolates biosynthesis in watercress hairy roots.