Fig. 3

Influence of salinity on isoprene production and ispS expression. a Isoprene production rates of selected Synechocystis strains are shown in the presence of 0, 2, or 4 % NaCl. Isoprene production is expressed in relation to optical density (OD₇₅₀; measure of cell density) over 24 h of phototrophic growth in the Synechocystis strains, which carry various constructs for isoprene synthesis (see Table 1). Statistical significant differences (p ≤ 0.05) to the strain # 642 at 0 % NaCl are marked by asterisk. b Salt (NaCl)-dependent expression of the ispS gene in the different Synechocystis strains. The relative expression (rnpB amount was used as internal loading control) of ispS was estimated by qPCR. Expression of ispS at 0 % NaCl was set to 1