ISOLATION AND CHARACTERIZATION OF GENE ENCODING β-AMYRIN SYNTHASE INVOLVED IN SAPONIN BIOSYNTHESIS FROM Talinum paniculatum (Jacq.) Gaertn.

• Main Author: QURROTUL AFIFAH - NIM : 21115006, IKA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/27947
• Institution: Institut Teknologi Bandung

<p align="justify">Talinum paniculatum or Javanese ginseng is a plant that is widely used in traditional medicine. The genus Talinum is known to produce oleanane-type triterpene saponins such as talinumoside I. This type of saponins has various pharmacological activities such as anticancer, antidiabetic, and anti inflammatory. The aims of this study were to isolate the gene encoding &#946;-Amyrin synthase (bAS), a key enzyme involved in the cyclization reaction of 2,3-oxidosqulane producing backbone of oleanane-type saponin &#946;-Amyrin and to analyze the correlation between the TpbAS gene expression level and saponin production in various plant organs. The TpbAS gene was isolated using degenerate primers and PCR 5 '/ 3' Rapid Amplification cDNA Ends (RACE). TpbAS gene expression level was analyzed in various organs using Reverse Transcriptase PCR (RT-PCR), whereas the saponin content was measured by spectrophotometer. The Coding DNA Sequence (CDS) of TpbAS consists of 2298 base pairs encoding a protein with 765 amino acid residues. In addition, regulatory elements were also identified in the form of (GA)n sequences and AATAAA sequences in the 5 '/ 3' Untranslated Region (UTR) which are predicted to play an important role in the process of transcription and protein expression. The amino acid sequence deduction showed DCTAE, QW, and WCYCR motifs that are conserved in all classes of oxidosqualene cyclase enzymes. The phylogenetic tree analysis also showed that the TpbAS gene has a very close relation to other plant oxidosqualene cyclase groups. Analysis showed that the level of TpbAS gene expression has a positive correlation with saponin concentration. These predicted that saponin is synthesized and accumulated in the same organs with the highest value in leaves. These findings are essential as an initial step to boost the saponin content and produce plant with valuable trait for pharmaceutical industry supply through metabolic engineering approach.<p align="justify">