Transcriptional response of Gemmatimonas phototrophica to changing light regimes [AP64_O2]

In this study, we provide a time-series analysis of the transcriptional response of Gemmatimonas phototrophica AP64T during the dark-to-light transition under aerobic and semiaerobic conditions. By analysing its transcriptome, focussing especially on PS-related genes, we tested the hypothesis that G. phototrophica might constitute an example of an anoxygenic phototroph on its evolutionary pathway from anaerobic to aerobic life-style. Overall design: G. phototrophica AP64T (= DSM 29774) was grown in an optimized liquid medium described earlier (Shivaramu et al., 2023) at 25°C. At the beginning of each experiment, the inoculum (approx. OD600 = 0.2) was diluted in 100 mL of a fresh medium to approx. OD600 = 0.03. Cultures were grown in triplicates aerobically (20% O2) or semiaerobically (10% O2) in the dark until reaching approx. OD600 = 0.2. Then cultures were illuminated with photon flux density of 100 µmol photons m-2 s-1. Sampling was done 2 and 8 hours after the light was switched on. Control set was sampled at dark.