Analysis of differential gene expression in a Streptococcus sanguinis ssaACB deletion mutant before and after addition of EDTA to deplete cellular manganese

The purpose of this study was to determine why manganese is required for the growth of Streptococcus sanguinis. The study employed a mutant derivative of S. sanguinis strain SK36 deleted for the genes encoding the manganese transporter SsaACB. The mutant strain, JFP169, was grown in a fermenter with constant aeration in BHI broth. RNA-seq was used to compare gene expression from samples taken 20 minutes prior to addition of 100 micromolar EDTA to samples taken 10, 25, and 50 min after addition. Samples were treated with xx to deplete ribosomal RNA, then sequenced on a MiSeq sequencer, producing paired-end 150-base reads. Sequences were trimmed and filtered and expression levels compared using the DE-Seq module in the Geneious Prime program. Overall design: Expression was compared at four time points, one 20 min prior to EDTA addition and the other three at 10, 25, and 50 min after EDTA addition. Four biological replicates were analyzed for each time point.