Background: Licorice is an herbal medicine applied extensively worldwide, and most of the
licorice for clinical consumption is provided by Glycyrrhiza uralensis Fisch. Evidence suggests that
there is a significant difference in the metabolite composition of licorice from different ecotypes.
Objective: To better understand the proteomic changes and molecular mechanisms of metabolite formation
in wild and cultivated Glycyrrhiza uralensis Fisch.
Methods: Firstly, we established a proteome database by annotating protein sequences according to the
genomic and transcriptomic data of G. uralensis. Then, iTRAQ and LC-MS/MS were applied to detect
significant protein changes between cultivated and wild G. uralensis. A total of 2751 validated proteins
were obtained with high confidence, and 333 were differentially expressed. Differentially expressed
proteins were identified and analysed by GO, KEGG, and STRING for network and pathway enrichment.
Ultimately, we combined the iTRAQ results with our previous investigation on metabolites to
understand the molecular mechanisms underlying metabolite accumulation.
Results: The results showed that differentially expressed proteins were mainly involved in the anabolism
of carbohydrates and important amino acids that participate in primary metabolism and secondary
metabolite synthesis. Another important pathway is the synthesis of flavonoids, which are generally accepted
as important bioactive constituents of G. uralensis, and the accumulation of flavonoids in different
synthesis stages in two ecotypes of G. uralensis was diverse. Therefore, the differentially abundant proteins
in wild and cultivated G. uralensis possibly resulted in differences in medicinal compounds.
Conclusion: Our study will provide novel clues for revealing the molecular mechanism of secondary
metabolite synthesis as well as quality formation in wild and cultivated G. uralensis.