design: Preparation of total RNA was performed basically by the hot phenol method as described in Damm et al. (2015). In detail, each cell pellet derived from 10 OD600 was resuspended in 1.6 ml icecold extraction buffer (10 mM NaOAc, 150 mM sucrose, pH 4.8) and equally distributed to two 2-mL tubes. To each 800-L sample, 75 L lysozyme solution (20 mg/ml in 1x TE buffer) was added, followed by incubation for 10 min at room temperature. Then 40 l of 20% SDS solution were added and components mixed by pipetting up and down. Cells was completely lysed by incubation for 90 s in a 65C water bath before adding 800 L acidic phenol (preheated to 65C). After thorough vortexing for 15 s, repeated inversion of reaction tubes and vortexing for another 15 s, samples were successively incubated for another 4 min at 65C, immediately shock-frozen shortly in liquid nitrogen, thawed for 2 min at 65C in the water bath, vortexed for 20 s and centrifuged for 10 min at 15,700 g. The upper aqueous phase was carefully transferred to a new 2-mL tube and the entire phenol extraction procedure was repeated for another two rounds. To each of the aqueous phases obtained from the three phenol extractions, 800 L chloroform was added and samples were vortexed for 30 s and centrifuged for 5 min at 15,700 g. Each aqueous phase was then carefully transferred to a 1.5-mL tube and the RNA was precipitated by addition of 0.8 volumes isopropanol and 1/10 volume 3 M NaOAc, pH 5.0, followed by storage for 1 h at -20C. After centrifugation for 30 to 40 min at 15,500 g / 4C, the RNA pellet was washed with 75% EtOH, air-dried and redissolved in 20 to 30 l ddH2O. RNA-seq experiments were performed in two biological replicates each.Small RNA species (< 200 nt) were isolated from total RNA samples using the RNeasy Mini Kit (Qiagen). Ribosomal RNA molecules were depleted using an in-house developed protocol (vertis Biotechnologie AG). Oligonucleotide adapters were ligated to the 5' and 3' ends. First-strand cDNA synthesis was performed using M-MLV reverse transcriptase and the 3'-adapter as primer. The resulting cDNA was PCR-amplified using a high-fidelity DNA polymerase (14 cycles). Purification was done using the Agencourt AMPure XP kit (Beckman Coulter Genomics). Samples were pooled in equimolar amounts and sequenced using an Illumina NextSeq 500 system with 75 bp read length.