Survey of five Artemisia species with different artemisinin contents in view of relative expression of 13 genes involved in artemisinin production, karyology, and nuclear DNA content
Ghasem Karimzadeh, Maryam Salehi, Mohammad Reza Naghavi, Hassanali Naghdi Badi and Sajad Rashidi Monfared
Tarbiat Modares University, Iran
University of Tehran, Iran
Institute of Medicinal Plants-ACECR, Iran
: J Plant Physiol Pathol
Abstract
Artemisinin, a sesquiterpene lactone, is an efficacious anti-malarial drug, effective against cancer, hepatitis, and schistosomiasis. Many Artemisia species produced lower artemisinin content than A. annua. Except for the latter, there are no published studies on the transcription factor and different sesquiterpene synthases competing for the same substrate, farnesyl diphosphate (FDP), which is a precursor of artemisinin. Leaves of five Artemisia species with different artemisinin contents were assessed in view of the relative expression of 13 genes involved in artemisinin production, karyology, and genome size. This study identified one novel plant sources of artemisinin (A. deserti, 6.40 mg g-1 DW) that performed as well as A. annua of Iran (6.27 mg g-1 DW), but inferior to A. annua cv. Anamed (14.50 mg g-1 DW) at flowering stage. Four species (A. annua, A. khorassanica, A. persica, and A. deserti) were diploid (2n = 2x = 18 m), while A. marschalliana was tetraploid (2n = 4x = 36 m). Among four diploids species, a difference of 9.97 pg in 2C DNA contents [ranged 4.02 (A. annua)-13.99 (A. deserti)] was distinguished despite having the same chromosome number while, the mean of 2C-value of A. marschalliana was 11.50 pg. The high artemisinin content of A. deserti is related to the highest genes (mainly AlDH1, CYP, ORA) expression. Because these genes in studied species were found to have a similar expression pattern, enabling us to suggest that ORA is a transcription factor regulating the promoters of artemisinin biosynthetic genes. The superior high-genome A. deserti had the highest expression of CPS, GAS, ORA, ALDH1 (178 fold), and CYP (150 fold), verifying that this species may have the vast metabolic capacities. It is noteworthy that this species has 3.5-fold 2C DNA amount compared to A. annua.
Biography
Ghasem Karimzadeh received a PhD in Plant Cell Biology from Cardiff University, Cardiff, UK in 1996. He is an Associate Professor in the Department of Plant Breeding, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. His research interest areas are cytogenetics, in vivo- & in vitro-polyploidy induction, ploidy level and secondary metabolites in medicinal plants, plant response to abiotic environmental stresses.
