Figure 4.

MAPK gene expression. The gene expression of Chlamydomonas MAPK3, MAPK5, MAPK6 and MAPK8 were studied in the wt (704) and nit2 (89.87) at different times, in medium without nitrogen (-N) and with ammonium (8 mM), nitrate (4 mM), or nitrite (2 mM). The gene expression was quantified by RT-qPCR, the value 0 was assigned to the expression level of internal standard gene ubiquitine ligase in each condition. Error bars indicate the standard deviation of three biological replicates. Comparisons were made by the Student’s t-test. (a) Indicates statistical differences (p < 0.05) compared to ammonium medium in the same strain and (b) compared to the wt strain in the same medium (see Materials and Methods section for further explanations).