Effects of Culture Conditions on Isoflavonoid Levels of Transformed and Non-Transformed Cultures of Lupinus -a Comparison of Suspension and Hairy Root Cultures

Abstract

Abstract Some highly productive suspension and hairy root cultures were found among several trans­formed cultures of Lupinus polyphyllus and L. hartwegii. A transformed suspension culture Lupo 30150 and a root culture Luha 15834 containing the highest specific isoflavone glucoside content were characterized and compared with normal phytohormone-dependent lines with respect to product stability as well as to their responsiveness to external triggers, e.g. response to changes in the medium. While phytohormone-dependent suspension cultures lost their ini­tial ability to form increased levels of isoflavonoids on phytohormone-free medium, the trans­formed phytohorm one-independent suspension Lupo 30150 remained a highly productive line, despite the fact that its specific levels decreased to 60% of the initial values during several years in liquid medium. Highest stability of product patterns and levels were noted for the transformed root culture. Phytohorm ones had little effect on growth and isoflavonoid levels in suspension cultures, while they reduced both strongly in root cultures. In the presence of 2,4-D the root culture changed into an aggregated low producing suspension culture from which the root state was recovered on phytohorm one-free medium. As long as the root state was main­ tained, isoflavonoid levels could not be distinctly improved by media variation while specific isoflavonoid levels of suspensions were increased by stress factors such as phosphate depletion. When suspensions were transferred to fresh medium phenylalanine ammonia-lyase was greatly induced within 24 h, while the activity remained nearly unchanged in root cultures.