Isolation and Expression Pattern of β-amyrin Synthase in Chicory (Cichorium intybus L.)

Medicinal plants have a range of significant impacts on human health due to their valuable bioactive compounds with medicinal properties. Chicory (Cichorium intybus L.) belongs to the family of Astracease, is one of the important medicinal plants which produces several types of secondary metabolites such as triterpenoid saponins. Triterpenoid saponins are the most important terpene compounds, which are often in glycosylated form as valuable substances have many applications in industry and medicine. β-amyrin synthase, an important member of the oxidosqualene cyclases family of enzymes in plants, play a crucial role in triterpene saponin biosynthesis. Because of the importance of saponins in chicory plants, partial isolation and expression of the encoding gene of β-amyrin synthase was aimed. RNA isolation, cDNA synthesis, partial cloning and nucleotide sequencing were successfully performed. Sequencing and bioinformatic analysis of the partial coding regions revealed that the partial isolated β-amyrin synthase gene in chicory is very similar to the β-amyrin synthase in other plant species, particularly Aster and Artemisia. Additionally, transcript gene expression analysis with semi-quantitative RT-PCR method and using GAPDH as reference gene was performed in leaf and root tissues of two different chicory genotypes. Results illustrated that expression levels of β-amyrin in root tissues was significantly higher than those in leaf tissues. Moreover, the transcript level of β-amyrin was considerably different between the two genotypes. The results of this study can be used in a complementary basic research in chicory and also to increase saponins through metabolic engineering.