Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 10, 2004
Publication Date: January 4, 2005
Citation: Dowd, M.K., Moss, S.C., Pelitre, S.M., Triplett, B.A. 2005. Optimal growth and secondary metabolite production from cotton hairy roots. Proc. Beltwide Cotton Conf., New Orleans, LA, p. 2122. http://www.cotton.org/beltwide/proceedings/2005/pdfs/3027.pdf Technical Abstract: Hairy root cultures are an ideal system to investigate metabolite production and regulation in cotton. As part of our studies on cotton hairy root cultures, experiments were conducted to optimize culture growth rate and secondary metabolite production. In addition to gossypol (a disesquiterpene with potentially valuable anti-cancer properties), transformants derived from both Gossypium barbadense and G. hirsutum contained measurable amounts of 6- methoxy-gossypol and 6,6’-dimethoxy-gossypol. Individual cultures exhibited considerable variability in the ability to produce gossypol. Media composition, culture time, and temperature were all found to influence culture growth and metabolite production. Growth rates were determined by gravimetric measurement, and gossypol levels were determined by HPLC analysis. To date, the highest growth rate and the greatest metabolite productivity was obtained from cultures grown on Gamborg B5 media. The optimal temperature for hairy root growth was 28 °C, and the optimal temperature for total gossypol level was 31 °C. Total gossypol productivity (gossypol level x culture mass) was slighter higher at 31 °C than at 28 °C. Variability and stability of gossypol production within individual high-producing cultures was also studied. Although considerable variability in gossypol levels was observed among cultures, the ability to produce gossypol was maintained over many media transfers. Total gossypol levels up to 4% (dry weight basis) have been obtained from some cultures.