Identifying Terpenoid Biosynthesis Genes in Euphorbia maculata via Full-Length cDNA Sequencing

Abstract

The annual herb Euphorbia maculata L. produces anti-inflammatory and biologically active substances such as triterpenoids, tannins, and polyphenols, and it is used in traditional Chinese medicine. Of these bioactive compounds, terpenoids, also called isoprenoids, are major secondary metabolites in E. maculata. Full-length cDNA sequencing was carried out to characterize the transcripts of terpenoid biosynthesis reference genes and determine the copy numbers of their isoforms using PacBio SMRT sequencing technology. The Illumina short-read sequencing platform was also employed to identify differentially expressed genes (DEGs) in the secondary metabolite pathways from leaves, roots, and stems. PacBio generated 62 million polymerase reads, resulting in 81,433 high-quality reads. From these high-quality reads, we reconstructed a genome of 20,722 genes, in which 20,246 genes (97.8%) did not have paralogs. About 33% of the identified genes had two or more isoforms. DEG analysis revealed that the expression level differed among gene paralogs in the leaf, stem, and root. Whole sets of paralogs and isoforms were identified in the mevalonic acid (MVA), methylerythritol phosphate (MEP), and terpenoid biosynthesis pathways in the E. maculata L. The nucleotide information will be useful for identifying orthologous genes in other terpenoid-producing medicinal plants.

Phytochemical screening and gas chromatography-mass spectrometry analysis of Euphorbia ingens organic root extract

“…The most abundant compounds in the natural products in general are terpenoids (Yang et al, 2020), however, the study findings reported low levels in terpenoids while a moderate level was reported by Njeru and Meshack (2016). Previous studies on differential gene expression analysis revealed that the expression level differed among gene paralogs involved in terpenoid biosynthesis in the leaf, stem, and root of other related plants (Jeon et al, 2022). Plants' terpenoids are anti-hyperglycemic, antiinflammatory, anti-parasitic, anti-viral, anti-cancer, antimicrobial and they render skin permissible to many drugs across cell membrane (Ramawat and Mérillon, 2013).…”