Ri-mediated transformation of Artemisia annua with a recombinant farnesyl diphosphate synthase gene for artemisinin production

A transgenic system was developed for Artemisia annua L. via Agrobacterium rhizogenes-mediated transformation. Using this system a cDNA encoding farnesyl diphosphate synthase (FDS) placed under a CaMV 35S promoter was transferred into Artemisia annua using Agrobacterium rhizogenes strain ATCC15834. Among the 150 hairy root lines established, 16 lines showed resistance to kanamycin (20 mg l-1). The intergration of FDS gene was confirmed by PCR and Southern blot analysis, and analysis of Northern blot revealed that the foreign FDS gene was expressed at the transcriptional level in three hairy root lines (F-1, F-24 and F-26 root line). F-1, F-24 and F-26 root lines grew faster than the control hairy root line. However, on the MS medium growth of F-26 root line was abnormal in that callus frequently formed. Analysis of artemisinin demonstrated that about 2–3 mg g-1 DW of artemisinin were then detected in the three root lines, which is about 3–4 times higher than that in the control hairy roots.