Comparison of expression pattern of some artemisinin biosynthesis related genes and phytochemical profile in Artemisia fragrans and Artemisia annua species

So far around 500 species of Artemisia have been found in different regions of the world, and among them 34 species are endemic to Iran. It has been evidenced that Artemisinin is one of the medicinal compounds found in Artemisia that has various medical properties, especially antimalarial. The main objective of the present study was to comprise phytochemical profile and expression pattern of some genes related to artemisinin biosynthesis pathway in A. fragrans and A. annua species.

In the present study, the accumulated artemisinin content in A. fragrans and A. annua species were detected using the high-performance liquid chromatography (HPLC) technique. Moreover, phytochemical compounds in leave tissue were identified using the gas chromatography–mass spectrometry (GC-MS) technique. The gene expression patterns for some artemisinin biosynthesis related genes including 4FPSF, DBR2, HMGR1, HMGR2, WIRKY, ADS, DXS, and SQS were comprised in two studied species. In each species, association between artemisinin content and the relative expression of investigated genes were determined through correlation analysis. All statistical analysis was performed based on three replication using R software.

Based on obtained results, there was observed a significant difference between two Artemisia species in terms of artemisinin content, and the highest content was recorded for A. fragrans. Using GC-MS analysis, in general 26 and 20 phytochemical compounds were identified in A. fragrans and A. annua species, respectively. Among identified compounds, eight compounds were similar in both species. Moreover, some compounds such as Comphor, 1,8-Cineole, 4-Terpineol, and Pinocarvone were most important. According to the gene expression analysis, the highest relative expression of 4FPSF, ADS, and DXS genes were recorded in A. annua, while the highest numbers of transcripts for SQS, HMGR1, HMGR2, DRB2, and WIRKY genes were estimated in A. fragrans. The results of correlation analysis for both species showed that artemisinin content significantly and positively correlated with the expression of ADS, DBR2, DXS, and HMGR1 genes. However, in A. annua species, the SQS gene was not expressed and there was no correlation between these genes and artemisinin content.

In general, the obtained results revealed a significant difference between two studied Artemisia species in terms of the artemisinin content and other phytochemical compounds. Furthermore, our results indicated that A. fragrans could be used as an ideal source for extract artemisinin and other compounds. Hence, conducting other supplementary studies on this species is recommended.