Fig. 3
Growth test demonstrating that the introduction of tCI into the chloroplast genome allows the temperature-dependent translation of functional CrCD protein from the CD/2* gene. Liquid cultures grown at 35 °C were spotted onto TAP agar containing no drug (left panel) or 2 mg/ml 5-fluorocytosine (5-FC; right panel) then incubated at different temperatures for 10 days. Three C. reinhardtii cell lines were used, all containing the CD/2* gene. In the cell line with no additional tRNA gene (−), CD/2* is not translated so the cells grow on 5-FC. In the cell line with trnWUCA encoding the constitutive version of the tRNA (+), CD/2* is translated at all growth temperatures and prevents growth on 5-FC. In the cell line with tCI, CrCD accumulation and subsequent growth inhibition depend on the temperature