FIG 4.

Heat map of changes in gene expression at elevated CO₂ for each of the six Microcystis strains. Gene expression changes were obtained by RT-qPCR applied to samples taken before and 20 h after increasing the pCO₂ level from 400 to 1,100 ppm. The color bar indicates log₂ values. Significant downregulated genes are shown in green, significant upregulated genes are shown in red, and nonsignificant changes (P > 0.05) or log₂ values between −0.8 and 0.8 are shown in black. Genes not measured are shown in white and genes absent in strains are marked with an “x”. Detailed RT-qPCR results are presented in Table S2 in the supplemental material.