Comparative transcriptomics of 5 Mesorhizobium strains (ORS3324, ORS3359, ORS3356, ORS3365, STM8773) under salt stress
Comparative transcriptomics of 5 Mesorhizobium strains (ORS3324, ORS3359, ORS3356, ORS3365, STM8773) under salt stress
Mesorhizobium strains were grown in 3 biological replicates in 100 mL of TY medium (Trypone yeast extract) in 1000 mL Erlenmeyer  flasks at 28C and 160 rpm up to exponential phase (Optical density of 0.7 to 0.9). When cultures reached exponential phase (around 16 hours), 100 mL of TY medium containing different concentrations of NaCl were added to the 100 ml of TY bacterial culture to reach a final concentration of NaCl of 300 mM for STM8773, ORS3356 and ORS3365; 150 mM for ORS3359; and 90 mM for ORS3324; for the \"salted\" conditions. Control condtiions were peroformed without salt. The cultures were further incubated 6 h at 28C and 160 rpm.  3.6 ml of each bacterial culture was added to 0.4 ml of ice cold stop buffer (5% phenol in ethanol) in a 15 ml falcon tube and directly centrifuged at 4C, 4000 rpm for 20 min. Supernatants were discarded and cells were snap frozen in liquid nitrogen and stored at -80cuntil extraction. Total RNA was perfromed using the RiboPureTM kit from Ambion, and quality verified on an Bioanalyser 2100 (Agilent). Two successive runs of of ribosomal RNA subtractions were perfomred (kit MicrobeExpress, Ambion).  Libraries construction were subcontracted to MGX Montpellier Genomix plateform ( Montpellier, France). Libraries were constructed using the Trueseq protocol of Illumina.