Fifty-seven accessions of torch ginger (Etlingera elatior) collected from seven states in Peninsular Malaysia were evaluated for their molecular characteristics using ISSR and SSR markers to assess the pattern of genetic diversity and association among the characteristics. Diversity study through molecular characterization showed that high variability existed among the 57 torch ginger accessions. ISSR and SSR molecular markers revealed the presence of high genetic variability among the torch ginger accessions. The combination of different molecular markers offered reliable and convincing information about the genetic diversity of torch ginger germplasm. This study found that SSR marker was more informative compared to ISSR marker in determination of gene diversity, polymorphic information content (PIC), and heterozygosity in this population. SSR also revealed high ability in evaluating diversity levels, genetic structure, and relationships of torch ginger due to their codominance and rich allelic diversity. High level of genetic diversity discovered by SSR markers showed the effectiveness of this marker to detect the polymorphism in this germplasm collection.
Panduratin A extracted from Boesenbergia rotunda is a flavonoid reported to possess a range of medicinal indications which include anti-dengue, anti-HIV, anti-cancer, antioxidant and anti-inflammatory properties. Boesenbergia rotunda is a plant from the Zingiberaceae family commonly used as a food ingredient and traditional medicine in Southeast Asia and China. Reports on the health benefits of secondary metabolites extracted from Boesenbergia rotunda over the last few years has resulted in rising demands for panduratin A. However large scale extraction has been hindered by the naturally low abundance of the compound and limited knowledge of its biosynthetic pathway.
Prenylation of aromatic natural products by membrane-bound prenyltransferases (PTs) is an important biosynthesis step of many bioactive compounds. At present, only a few plant flavonoid-related PT genes have been functionally characterized, mainly due to the difficulties of expressing these membrane proteins. Rapid and effective methods to produce functional plant membrane proteins are thus indispensable. Here, we evaluated expression systems through cell-based and cell-free approaches to express Boesenbergia rotunda BrPT2 encoding a membrane-bound prenyltransferase. We attempted to express BrPT2 in Escherichia coli and tobacco plants but failed to detect this protein using the Western-blot technique, whereas an intact single band of 43 kDa was detected when BrPT2 was expressed using a cell-free protein synthesis system (PURE). Under in vitro enzymatic condition, the synthesized BrPT2 successfully catalyzed pinostrobin chalcone to pinostrobin. Molecular docking analysis showed that pinostrobin chalcone interacts with BrPT2 at two cavities: (1) the main binding site at the central cavity and (2) the allosteric binding site located away from the central cavity. Our findings suggest that cell-free protein synthesis could be an alternative for rapid production of valuable difficult-to-express membrane proteins.