Fig. 1

Characterization and growth of Synechococcus elongatus transgenic strains in media with phosphite. a Transgenic strains SeptxD-1 to -6 were grown in BG-11 media supplemented with 1.8 mM of phosphite (Phi) as phosphorus source. S. elongatus PCC 7942 (SeWT) was cultured in media with Phi and phosphate (Pi, 0.2 mM) as controls. Cultures were photographed at 0 and 8 days after inoculation. b Cell number was determined every 2 day during 8 days. c Relative expression of the ptxD gene in S. elongatus transgenic strains (SeptxD-1 to -6). S. elongatus PCC 7942 (SeWT) strain was used as negative control; SerpoD and SernpB genes were used as housekeeping genes. d PtxD enzymatic activity expressed as Arbitrary Units of Fluorescence (A.U.F.) determined in SeptxD-2 and SeWT as negative control. Values are the mean of three replicates ± SE (n = 3). Different letters indicate significant differences (ANOVA test, P < 0.05)