(A, B) The effect of the pH and (B, C) sodium carbonate in the growth medium (A, C) on the protein and (B) transcript levels of FDP. (D) Protein immunoblots demonstrating the accumulation of bicarbonate transporter (SbtA) and NDH-1 subunits (NdhD3 and NdhJ) in the cells grown at different pH and CO2 concentration. Cells were pre-grown at different pH levels (+Na2CO3) under HC for 3 days, harvested, resuspended in fresh BG-11 (pH maintained), adjusted to OD750≈0.2 and shifted to LC for 4 days. At pH 7.5, the cells were grown at LC in the presence (+ Na2CO3, at final concentration of 0.189 mM) or in the absence (- Na2CO3) of sodium carbonate (B, C). Transcript abundance is presented as mean ± SD, n = 2–4 biological replicates, asterisks indicate a statistically significant difference to the WT (*p<0.05; ***p<0.001) (Figure 3—source data 1). Numbers 1–3 indicate different biological replicates. 25% and 50% correspond to 1:4, 1:2 diluted total protein sample, and 100% indicates undiluted total protein sample.