Isolation and Characterization of Cell Lines of Valeriana wallichii Resistant to Trifluoroleucine

Abstract

Two cell lines of Valeriana wallichii DC resistant to the leucine analogue 5′,5′,5′-trifluoro-D,L-leucine have been isolated. The two lines (V125, V 500) accumulated higher amounts of aspartic acid (up to 5 fold) and glutamic acid (up to 57 fold) compared to the initial cultures; furthermore, V 500 accumulated comparatively high amounts of valine (R∼15 fold) and leucine (∼ 37 fold). The activity of acetohydroxyacid-synthetase, the key enzyme in the biosynthetic pathway of branched-chain amino acids, was little affected by these amino acids in V 500. In V 125 the enzyme showed no change in feedback control properties. While in the literature there is some evidence that leucine degradation products are incorporated into terpenoid compounds, the high pool of leucine in V 500 did not induce a higher accumulation of terpenoid derived compounds such as valepotriates, volatile terpenes and sterols.