Roots as an enhancing factor for the production of artemisinin in shoot cultures of Artemisia annua

Artemisinin was produced in differentiated shoot cultures of Artemisia annua L. but was undetected in callus or cell cultures. The growth regulators benzyladenine, kinetin, chlormequat, and daminozide, at concentrations which severely reduced rooting, reduced artemisinin production. A highly significant correlation (1% level) was observed between shoot artemisinin content and number of roots (r=0.775^**), but shoot number and artemisinin content were unrelated (r=-0.198). Benzyladenine increased shoot proliferation at 0.5 and 5.0 M, but decreased root production at 0.5, 5.0, and 50 M. The highest levels of artemisinin production (0.287% DW) were obtained in hormone-free medium when root production was maximized. Removal of roots from shoots cultured in hormone-free liquid medium reduced shoot artemisinin by 53% and shoot arteannuin B by 60%. Neither artemisinin, arteannuin B, or artemisinic acid were detected from roots developed in semi-solid or liquid medium.Abbreviations BA benzyladenine - CCC chlormequat - DW dry weight - FW fresh weight - GA₃ gibberellic acid - GC/MS gas chromatography/mass spectrometry - HPLC-EC high-performance liquid chromatography with electrochemical detection - MS Murashige & Skoog basal medium - 2,4-d 2,4-dichlorophenoxyacetic acid Journal paper no. 14558 of Purdue Agricultural Research Progress