Transcriptome analysis of the Antarctic psychrotrophic bacterium Psychrobacter sp G in response to temperature stress

The key functional genes involved in temperature adaption of the Antarctic psychrotrophic bacterium Psychrobacter sp. G. were identified by transcriptomic sequencing. We analyzed the global transcriptional profile of Psychrobacter sp. G under cold stress (0A degrees C) and heat stress (30A degrees C), with the optimal growth temperature 20A degrees C as the control. There were large alterations of the transcriptome profile, including significant upregulation of 11 and 12 transcripts as well as significant downregulation of 47 and 42 transcripts in the cold and heat stress groups, respectively, compared to the control. The expression of various genes encoding enzymes and transcriptional regulators, including PfpI and TetR family transcriptional regulators under heat stress, as well as the expression of DEAD/DEAH box helicase and the IclR family of transcriptional regulators under cold stress, were upregulated significantly. The expression of several genes, most affiliated with TonB-dependent receptor and siderophore receptor, was downregulated significantly under both heat and cold stress. Many of the genes associated with the metabolism of fatty acid and ABC transporters were regulated differentially under different temperature stress. The results of this survey of transcriptome and temperature stress-relevant genes contribute to our understanding of the stress-resistant mechanism in Antarctic bacteria.