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Triterpenoid gene expression and phytochemical content in Iranian licorice under salinity stress

  • Zahra Shirazi
  • Ali AalamiEmail author
  • Masoud Tohidfar
  • Mohammad Mehdi Sohani
Original Article


Licorice is a well-known medicinal plant, containing various secondary metabolites of triterpenoid and phenolic families. The aim of this study is to evaluate the effect of salinity stress on the expression of key genes involved in the biosynthetic pathway of triterpenoids such as glycyrrhizin, betulinic acid, soyasaponins, and phytosterols in licorice root, as well as providing a phonemic platform to characterize antioxidant properties, glycyrrhizin, and total phenolic content. This study also includes measuring the gene expression level and glycyrrhizin content in leaves and roots of control plants. The studied genes included squalene synthase (SQS1 and SQS2), β-amyrin synthase (bAS), lupeol synthase (LUS), cycloartenol synthase (CAS), β-amyrin 11-oxidase (CYP88D6), and β-amyrin 24-hydroxylase (CYP93E6). Our results revealed that all of the mentioned genes were upregulated following the stress condition with different transcription rates. The highest increase (12-fold) was observed for the expression of the LUS gene, which is related to the betulinic acid pathway. Also, the highest content of glycyrrhizin was observed at 72 h post-treatment, which was consistent with the upregulated transcription levels of the glycyrrhizin pathway genes especially SQS1 and CYP88D6 at the same time. Correlation and stepwise regression analysis proved the key role of SQS1 gene in the biosynthetic pathway of glycyrrhizin. Antioxidant activity and phenolic content also were increased following stress condition. A comparison between the expression levels of SQS1 and other genes involved in the production of glycyrrhizin, phytosterols, and soyasaponins revealed a similar transcription trend, which shows the gene expression in the roots was significantly higher than the leaves. In contrast, SQS2 and LUS genes displayed a higher expression in leaf tissues. The genes related to betulinic acid biosynthetic pathway exhibited an expression rate different from other triterpenoid pathway genes, which could be observed in the leaves and roots of control plants and the roots of salt-treated plants. Furthermore, results showed that these two SQS genes have different expression rates due to different plant tissues (roots and leaves) and stress conditions. Importantly, in contrast to previous reports, we detected the glycyrrhizin in leaf tissues. This result may indicate the presence of a different genetic background in native Iranian licorice germplasm.


Gene expression Glycyrrhiza glabra Glycyrrhizin Quantitative real-time PCR Secondary metabolites 



β-Amyrin synthase


Cycloartenol synthase


β-Amyrin 11-oxidase


β-Amyrin 24-hydroxylase


Farnesyl diphosphate


Gibberellic acid


High-performance liquid chromatography


Lupeol synthase


Methyl jasmonate


Oxidosqualene cyclases


Quantitative reverse transcription PCR


Squalene synthase



The authors would like to express their sincere gratitude to the Department of Plant Biotechnology, University of Guilan, Rasht, Iran.


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Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2019

Authors and Affiliations

  • Zahra Shirazi
    • 1
  • Ali Aalami
    • 1
    Email author
  • Masoud Tohidfar
    • 2
  • Mohammad Mehdi Sohani
    • 1
  1. 1.Department of Biotechnology, Faculty of Agricultural SciencesUniversity of GuilanRashtIran
  2. 2.Department of Plant Biotechnology, Faculty of Life Science and BiotechnologyShahid Beheshti University, G.C.TehranIran

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