THE EFFECT OF PHYTOHORMONES ON GROWTH AND ARTEMISININ PRODUCTION IN ARTEMISIA ANNUA HAIRY ROOTS

• Published in: In vitro cellular & developmental biology. Plant 2005-01, Vol.41 (1), p.47-53
• Main Authors: WEATHERS, P. J., BUNK, G., McCOY, M. C.
• Format: Article
• Language: English
• Subjects: abscisic acid; Artemisia annua; artemisinin; Artemisinins; Auxins; benzyladenine; biomass; Cytokinins; ethylene; gibberellins; Hormones; isopentenyladenine; Metabolic Engineering/Secondary Metabolism; metabolism; Plant growth regulators; Plant roots; Plants; Root growth; Root tips; roots; terpenoid; transformed roots; Weather
• ISSN: 1054-5476; 1475-2689
• DOI: 10.1079/IVP2004604

Few studies have focused on the effect of a broad range of phytohormones on growth and secondary metabolism of a single hairy root species. We measured growth, development, and production of the antimalarial drug, artemisinin, in Artemisia annua hairy roots in response to the five main hormones: auxins, cytokinins, ethylene, gibberellins (GA), and abscisic acid (ABA). Single roots grown in six-well plates in medium B5 with 0.01 mg l−1 (0.029 μM) GA3 produced the highest values overall in terms of the number of lateral roots, length of the primary root, lateral root tip density, total lateral root length, and total root length. When the total root lengths are compared, the best conditions for stimulating elongation appear to be: GA 0.01 mg l−1 (0.029 μM) > ABA 1.0 mg l−1 (3.78 μM)=GA 0.02 mg l−1 (0.058 μM). Bulk yields of biomass were inversely proportional to the concentration of each hormone tested. All cultures provided with ABA yielded the highest amount of biomass. Both 6-benzylaminopurine and 2-isopentenyladenine inhibited root growth, however, only 2-isopentenyladenine stimulated artemisinin production, more than twice that of the B5 controls, and more than any other hormone studied. These results will prove useful in increasing hairy root growth and artemisinin production.