Statistical analysis of elicitation strategies for thiarubrine A production in hairy root cultures of Ambrosia artemisiifolia

Elicitation strategies were studied for yield enhancement of thiarubrine A, a secondary metabolite and a potential pharmaceutical, produced by hairy r oot cultures of Ambrosia artemisiifolia. Abiotic elicitation was performed using vanadyl sulfate solution and biotic elicitation using autoclaved cell wall filtrates of the fungi Protamyces gravidus, a pathogen of A. artemisi ifolia and Botrytis cinereae. The factors considered were age of the cultur e, concentration of the elicitor used and the time period of exposure or co ntact. Statistical methods were used to determine the strength of the inter action between the various factors and their response on the yield of the s econdary metabolite. The maximum increase in the yield relative to the cont rol, 8-fold corresponding to 569 mu g g(-1) of biomass, was observed when 1 6-day-old cultures were elicited with 50 mg l(-1) of vanadyl sulfate for a time period of 72 h. The maximum yield of 647 mu g g(-1) was achieved when the cultures were exposed to 5 mu M autoclaved cell wall filtrates of P. gr avidus for a time period of 48 h. The yield increase was 3-fold in the case of elicitation with autoclaved cell wall filtrates of B. cinereae. The met hodology used in this report can be extended to determine the optimum condi tions of other elicitors. (C) 2000 Elsevier Science B.V. All rights reserve d.