Improving galegine production in transformed hairy roots of Galega officinalis L. via elicitation

Galega officinalis L. is an herbaceous legume used to treat symptoms associated with hyperglycemia or diabetes mellitus because of its dominant alkaloid, galegine. In this study, we induced hairy roots in this plant using Rhizobium rhizogenes strain A4, and investigated the effect of type, concentration, and duration of elicitor application on galegine content and some phytochemical characteristics in the hairy roots. Hence, the best growing hairy root line in terms of growth rate was selected and subcultured for treatment with elicitors. Then, at the end of the log phase of growth, chitosan (100, 200, and 400 mg/L), salicylic acid (100, 200, and 300 mM), and ultrasound (1, 2, and 4 min) were applied to hairy roots culture medium. High-performance liquid chromatography (HPLC) showed that the content of galegine was significantly increased after elicitation compared with the control. Thus, the highest content of galegine (14.55 mg/g FW) was obtained 2 days after elicitation when ultrasonic waves were applied to the hairy root culture medium for 4 min. Also, elicitation resulted in a significant increase in the content of total phenol, flavonoid, H2O2 and MDA compared with the control. So that the highest total flavonoid content was obtained in hairy roots that were treated with ultrasonic waves for 4 min and harvested 2 days after elicitation; while, application of 400 mg/L chitosan for 4 days resulted in the highest total phenol (16.84 mg/g FW).

Automated summary

Galega officinalis L. is an herbaceous legume that contains galegine, a dominant alkaloid used to treat hyperglycemia or diabetes mellitus. In this study, hairy roots were induced in Galega officinalis using Rhizobium rhizogenes strain A4, and the effect of different elicitors on galegine content and other phytochemical characteristics was investigated. Results showed that ultrasound treatment significantly increased galegine content in the hairy roots, as well as the content of total phenol, flavonoid, H2O2, and MDA.