TRANSIENT STUDIES OF TIGHT-ADAPTED CULTURES OF HAIRY ROOTS OF CATHARANTHUS-ROSEUS - GROWTH AND INDOLE ALKALOID ACCUMULATION

Cultures of C. roseus transgenic (''hairy'') root clones LBE-6-1 and L BE-4-2 were adapted with periodic daily illumination to investigate th e effect of light on growth and nutrient utilization, and the accumula tion of the indole alkaloids. Light-adapted roots appeared green and h ad radially thickened morphology compared with dark-grown controls, Th eir growth rates were higher than dark-grown controls, with 45% lower doubling times: LBE-6-1, 3.6 days; LBE-4-2, 2.8 days. Relative to dark -grown controls, light-adapted growth increased the biomass (DW) of LB E-6-1 by 25%, but had no effect on the DW of LBE-4-2. The macronutrien ts NH4+, NO3-, P-i, and sugars, were depleted completely by light-adap ted root cultures in that order. The specific and total levels of the indole alkaloid serpentine was enhanced and of tabersonine was lowered in both root clones, while the overall trends of growth and non-growt h association of tabersonine and serpentine, respectively, remained un altered by light adaptation. Ajmalicine accumulation was enhanced in L BE-6-1, but lowered in LBE-4-2; its accumulation was growth-associated in dark-grown LBE-6-1, but appeared non-growth associated in light-ad apted cultures. The accumulation of tabersonine-related compounds, loc hnericine, and horhammericine exhibited growth-associated trends, and were either negatively affected or unaffected by light adaptation of L BE-6-1. Neither vindoline nor its precursor, deacetylvindoline, was de tected. (C) 1998 John Wiley & Sons, Inc.