Assessment of Iranian endemic Artemisia khorassanica: karyological, genome size, and gene expressions involved in artemisinin production.

The species of Artemisia, one of the largest genera of the family Asteraceae, are frequently utilized for the treatment of diseases such as malaria, hepatitis, cancer, inflammation, and infections by fungi, bacteria, and viruses. Karyological studies were performed on 18 Artemisia khorassanica populations: eleven were diploid (2n = 18) and seven were tetraploid (2n = 36). The mean chromosome lengths were 3.61 and 3.84 µm for diploids and tetraploids, respectively. Two chromosome types ("m", "sm") formed karyotype formulas "18m" for diploids and "36m" and "34m + 2sm" for tetraploids. The mean 2C DNA contents were 5.91 and 11.53 pg in diploids and tetraploids, respectively. The transcription levels of key genes involved in artemisinin production were compared in diploid (B, D, H) and tetraploid (O, P, R) A. khorassanica relative to A. annua as a standard species. No artemisinin content was detected in diploid and tetraploid A. khorassanica populations. No significant diefrences were detected between diploids and tetraploids in terms of DXR , HMGR, FDS, and ADS gene expression. This implies that most of the genomic amplification likely occurs in the amount of repetitive DNA and not in unique sequences. The DBR2 gene was expressed in the diploid A. khorassanica in a low amount but silenced in the autotetraploid A. khorassanica.