Q-299. Global Transcriptional and Metabolite Analysis of Desulfovibrio vulgaris Hildenborough Responses to Long-Term Exposure to Elevated NaCl

Z. He1,2,3, E. Baidoo4,3,5, A. Zhou1,3, Q. He6,2,3, P. Benke4,3, R. Phan4,3, M. Joachimiak4,3, M. W. Fields7,2,3, A. Mukhopadhyay4,3, E. J. Alm4,3, K. Huang4,3, J. D. Wall8,3, T. C. Hazen4,3, J. D. Keasling4,3,5, A. P. Arkin4,3, J. Zhou1,2,3;
1The Univ. of Oklahoma, Norman, OK, 2Oak Ridge Natl. Lab., Oak Ridge, TN, 3Virtual Inst. for Microbial Stress and Survival, Berkeley, CA, 4Lawrence Berkeley Natl. Lab., Berkeley, CA, 5Univ. of California, Berkeley, CA, 6The Univ. of Tennessee, Knoxville, TN, 7Montana State Univ., Bozeman, MT, 8Univ. of Missouri, Columbia, MO.

The mechanisms of salt adaptation were studied in Desulfovibrio vulgaris Hildenborough using global transcriptional and metabolite analyses. The growth of D. vulgaris was inhibited by high salinity, and salt inhibition could be relieved by an addition of amino acids (e.g., tryptophan) or yeast extract. Salt shock (sudden increase in salt concentration) and salt adaptation (inoculating cells in the medium containing high concentrations of salt) showed a marked difference in respective transcriptomes. Salt adaptation induced expression of genes encoding proteins related to amino acid biosynthesis, formate dehydrogenases, histidine kinases, response regulators, specific transporters, heat-shock proteins, and peptidases. Genes involved in ribosomal protein synthesis, and energy metabolism were repressed. Genes involved in glycine/betaine/proline ABC transport, Na+/H+ transport, K+ uptake and transport, proline biosynthesis and transport, and glycerol biosynthesis and transport were not significantly affected. Metabolite assays suggested that some amino acids (e.g. glutamate) may accumulate as osmoprotectants in D. vulgaris. A conceptual model is proposed to link our observed results to currently available knowledge for further understanding the mechanisms of adaptation of D. vulgaris to sodium chloride.