Project description:Sinorhizobium meliloti lives as a soil saprophyte, and engages in a nitrogen fixing symbiosis with plant roots. To succeed in such diverse environments, the bacteria must continually adjust gene expression. Transcriptional plasticity in eubacteria is often mediated by alternative sigma factors interacting with core RNA polymerase. The S. meliloti genome encodes 14 of these alternative sigmas, including 11 extracytoplasmic function (ECF) sigmas. We used custom Affymetrix Symbiosis Chips to characterize the global transcriptional response of S. meliloti overexpressing the ECF sigma factor, RpoE2. Our work identifies over 200 genes whose expression is dependent on RpoE2.
Project description:Sinorhizobium meliloti can live as a soil saprophyte, and can engage in a nitrogen fixing symbiosis with plant roots. To succeed in such diverse environments, the bacteria must continually adjust gene expression. Transcriptional plasticity in eubacteria is often mediated by alternative sigma factors interacting with core RNA polymerase. The S. meliloti genome encodes 14 of these alternative sigmas, including two putative RpoH (heat shock) sigmas. We used custom Affymetrix Symbiosis Chips to characterize the global transcriptional response of S. meliloti rpoH1, rpoH2 and rpoH1 rpoH2 mutants during heat shock and stationary phase growth. Under these conditions, expression of over 300 genes is dependent on rpoH1 and rpoH2.
Project description:Sinorhizobium meliloti can live as a soil saprophyte, and can engage in a nitrogen fixing symbiosis with plant roots. To succeed in such diverse environments, the bacteria must continually adjust gene expression. Transcriptional plasticity in eubacteria is often mediated by alternative sigma factors interacting with core RNA polymerase. The S. meliloti genome encodes 14 of these alternative sigmas, including two putative RpoH (heat shock) sigmas. We used custom Affymetrix Symbiosis Chips to characterize the global transcriptional response of S. meliloti rpoH1, rpoH2 and rpoH1 rpoH2 mutants during heat shock and stationary phase growth. Under these conditions, expression of over 300 genes is dependent on rpoH1 and rpoH2. Gene expression profiling of Sinorhizobium meliloti Rm1021 and its isogenic rpoH1, rpoH2, and rpoH1rpoH2 mutants, subjected to heat shock or stationary phase growth, was performed using custom Affymetrix GeneChips
Project description:Sinorhizobium meliloti lives as a soil saprophyte, and engages in a nitrogen fixing symbiosis with plant roots. To succeed in such diverse environments, the bacteria must continually adjust gene expression. Transcriptional plasticity in eubacteria is often mediated by alternative sigma factors interacting with core RNA polymerase. The S. meliloti genome encodes 14 of these alternative sigmas, including 11 extracytoplasmic function (ECF) sigmas. We used custom Affymetrix Symbiosis Chips to characterize the global transcriptional response of S. meliloti overexpressing the ECF sigma factor, RpoE2. Our work identifies over 200 genes whose expression is dependent on RpoE2. The gene expression profile of Sinorhizobium meliloti strain CL150 carrying the rpoE2 gene on a plasmid, where it was expressed from a melibiose-inducible promoter (the S. meliloti PmelA promoter), was compared to the gene expression profile of CL150 carrying the corresponding empty vector (pCAP11). CL150 is an Rm1021 strain that has been corrected for two point mutations: it is wild type for ecfR1 and pstC.
Project description:We characterized transcriptomes of a Sinorhizobium meliloti wild type strain (CL150) expressing either Ca. Liberibacter asiaticus ctrA or Sinorhizobium meliloti ctrA
Project description:We characterized transcriptomes of a Sinorhizobium meliloti rpoH1rpoH2 deletion mutant (RFF231; Lang et al. 2018, mSphere 3:e00454-18) expressing either Ca. Liberibacter asiaticus rpoH or Sinorhizobium meliloti rpoH1
Project description:Investigation of whole genome gene expression level changes in a Sinorhizobium meliloti 1021 rpoH1 rpoH2 double mutant, compared to the wild-type strain. The mutations engineered into this strain render it deficient in symbiotic nitrogen fixation. The mutants analyzed in this study are further described in Mitsui, H, T. Sato, Y. Sato, and K. Minamisawa. 2004. Sinorhizobium meliloti RpoH1 is required for effective nitrogen-fixing symbiosis with alfalfa. Mol Gen Genomics 271:416-425.
Project description:Analysis of the RNA-seq reads confirmed that transcription of many of the previously identified Pho-regulon genes of Sinorhizobium meliloti was regulated by the availability of inorganic phosphate in the media. The transcriptional start sites of many of the Pho-regulon genes as determined by RNA-seq reads were found to correspond to those determined from primer extension analysis.