Evaluation of phenolic compounds, antioxidant and antimicrobial activities from transgenic hairy root cultures of gherkin (Cucumis anguria L.)

• Hairy roots of Cucumis anguria grew faster than normal roots.
• Stable integration of transgenes was confirmed.
• Production of phenolic compounds was higher in hairy roots than in in vitro grown roots.
• Biological activity was higher in hairy roots than control roots.

The production of secondary metabolites from hairy root cultures of gherkin (Cucumis anguria L.) along with their antioxidant and antimicrobial activities were studied. The explants from in vitro seedlings were inoculated with Agrobacterium rhizogenes strain KCTC 2703 for the induction of hairy roots. Transgenic clones of hairy roots were confirmed by polymerase chain reaction (PCR) and reverse transcription-PCR using rolC specific primers. Transgenic hairy roots developed in MS liquid medium supplemented with 3% sucrose exhibited the highest accumulation of biomass 98.55 g/l fresh mass (FM) and 10.15 g/l dry mass (DM) were observed at 21 days. Biomass accumulation of hairy root lines was 9.3-fold higher compared to in vitro grown roots. Moreover, transgenic hairy roots effectively produced several phenolic compounds, such as flavonols, hydroxycinnamic and hydroxybenzoic acids derivatives. Due to these metabolic changes, the antioxidant and antimicrobial activities were increased with hairy roots compared to non-transformed roots. The total phenolics, flavonoids content, antioxidant and antimicrobial activity were higher in hairy roots compared to non-transformed roots. Our study described the greater potentiality of C. anguria hairy root cultures for the production of important phenolic compounds and uses of their biological activities.