Biosynthesis of essential oil compounds in Ocimum tenuiflorum is induced by abiotic stresses

Abstract

The herb holy basil (Ocimum tenuiflorum) is rich in essential oil, which is important in pharmaceutical, nutraceutical, cosmetic, and food industries. O. tenuiflorum grows well in tropical, subtropical, and warm temperate regions. To induce essential oil biosynthesis, holy basil plants were exposed to cold or drought stress for 5 days. Gas chromatography-mass spectrometry (GC–MS) analyses revealed that essential oil components including eugenol, methyl eugenol, and β-caryophyllene were significantly accumulated in 30-day-old juvenile and 130-day-old pre-flowering plants. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that expressional levels of OtEOMT transcript increased by almost 5-fold following the juvenile stage, and by 16.78- to 66.02-fold following the pre-flowering stage among cold-treated plants. These results suggest a biotechnological strategy to increase essential oil content by treating holy basil plants with cold or drought stress at the juvenile and pre-flowering stages.

Keywords:

• Abiotic stresses
• β-caryophyllene
• eugenol
• methyl eugenol
• Ocimum tenuiflorum
• OtEOMT

Authors’ contributions

CTTN designed the research, conducted experiments, and wrote the manuscript. JHL, WSC, and NHN contributed critical technical assistance to the experiments. J-JC supported the research and edited the manuscript.

Disclosure statement

The authors declare that they have no conflicts of interest related to this study.

Additional information

Funding

This work was supported by the National Research Foundation of Korea (grant no. 2020R1I1A1A01066341).