Expression profiles of selected ncRNAs. The individual probe intensities of six selected ncRNAs are shown during free-living growth (early exponential, late exponential and stationary phase) and symbiosis (two and three weeks after plant inoculation). The summary expression values of the probe intensities (left) and RT-qPCR confirmations of the ncRNA expression levels (right) are given below each profile. The mean values and standard deviation of three RT-qPCRs are shown. Genes are represented by bars and arrows indicate the direction of transcription. (A) TPPb RS is a thiamin pyrophosphate-sensing riboswitch located on plasmid p42B; (B) ReC11 is highly similar to a previously experimentally verified sRNA in S. meliloti 1021 [41, 45]; (C, D, E, F) ReC43, ReC49, ReC27, ReC62 are novel candidate ncRNAs.