Transcriptome Sequencing ofGynostemma pentaphyllumto Identify Genes and Enzymes Involved in Triterpenoid Biosynthesis

Abstract

G. pentaphyllum(Gynostemma pentaphyllum), a creeping herbaceous perennial with many important medicinal properties, is widely distributed in Asia. Gypenosides (triterpenoid saponins), the main effective components ofG. pentaphyllum, are well studied. FPS (farnesyl pyrophosphate synthase), SS (squalene synthase), and SE (squalene epoxidase) are the main enzymes involved in the synthesis of triterpenoid saponins. Considering the important medicinal functions ofG. pentaphyllum, it is necessary to investigate the transcriptomic information ofG. pentaphyllumto facilitate future studies of transcriptional regulation. After sequencingG. pentaphyllum, we obtained 50,654,708 unigenes. Next, we used RPKM (reads per kilobases per million reads) to calculate expression of the unigenes and we performed comparison of our data to that contained in five common databases to annotate different aspects of the unigenes. Finally, we noticed that FPS, SS, and SE showed differential expression of enzymes in DESeq. Leaves showed the highest expression of FPS, SS, and SE relative to the other two tissues. Our research provides transcriptomic information ofG. pentaphyllumin its natural environment and we found consistency in unigene expression, enzymes expression (FPS, SS, and SE), and the distribution of gypenosides content inG. pentaphyllum. Our results will enable future related studies ofG. pentaphyllum.