The effect of different temperatures on fatty-acid synthesis and polyunsaturation in cell suspension cultures

Cell suspension cultures of Catharanthus roseus G. Don, Glycine max (L.) Merr. and Nicotiana tabacum L. were incubated with ¹⁴C]acetate, ¹⁴C]oleic acid and ¹⁴C]linoleic acid at five different temperatures ranging from 15 to 35° C. When the incubation temperature was increased, ¹⁴C]acetate was incorporated preferentially into ¹⁴C]palmitate, with a concomitant drop in ¹⁴C]oleate formation. Between 15 and 20° C, ¹⁴C]oleic acid accumulated in C. roseus cells. In all cultures, optimum desaturation of ¹⁴C]oleic acid to ¹⁴C]linoleic acid occurred between 20 and 25° C, and in G. max this was also the optimal range for desaturation of ¹⁴C]linoleic acid to ¹⁴C]linolenic acid. Elongation of ¹⁴C]palmitic acid was inhibited when cultures grown at 15° C for 25 h were subsequently incubated with ¹⁴C]acetate at 25° C. ¹⁴C]oleic acid accumulated in G. max and C. roseus cultures grown at 35° C for 25 h and subsequently incubated at 25° C. Desaturation of ¹⁴C]oleic acid increased up to 25° C, but then decreased or leveled off depending on the cell line and on the temperature prior to incubation.