Project description:Legumes interact with nodulating bacteria that convert atmospheric nitrogen into ammonia for plant use. This nitrogen fixation takes place within root nodules that form after infection of root hairs by compatible rhizobia. Using cDNA microarrays, we monitored gene expression in soybean (Glycine max) inoculated with the nodulating bacterium Bradyrhizobium japonicum 4, 8, and 16 days after inoculation (dai), time points that coincided with nodule development and the onset of nitrogen fixation. This experiment identified several thousand genes that were differentially expressed in response to B. japonicum inoculation. Expression of 27 genes was analyzed by qRT-PCR and their expression patterns mimicked the microarray results confirming integrity of analyses. The microarray results suggest that B. japonicum reduces plant defense responses during nodule development. In addition, the data revealed a high level of regulatory complexity (transcriptional, post-transcriptional, translational, post-translational) that is likely essential for development of the symbiosis and adjustment to an altered nutritional status. Keywords = symbiosis Keywords = nodulation Keywords = rhizobium Keywords = defense Keywords = ANOVA Keywords = plant loop design, 7 samples, 7 comparison, 2 technical repeats including dye swaps, 4 biological repeats
Project description:Legumes interact with nodulating bacteria that convert atmospheric nitrogen into ammonia for plant use. This nitrogen fixation takes place within root nodules that form after infection of root hairs by compatible rhizobia. Using cDNA microarrays, we monitored gene expression in soybean (Glycine max) inoculated with the nodulating bacterium Bradyrhizobium japonicum 4, 8, and 16 days after inoculation (dai), time points that coincided with nodule development and the onset of nitrogen fixation. This experiment identified several thousand genes that were differentially expressed in response to B. japonicum inoculation. Expression of 27 genes was analyzed by qRT-PCR and their expression patterns mimicked the microarray results confirming integrity of analyses. The microarray results suggest that B. japonicum reduces plant defense responses during nodule development. In addition, the data revealed a high level of regulatory complexity (transcriptional, post-transcriptional, translational, post-translational) that is likely essential for development of the symbiosis and adjustment to an altered nutritional status. Keywords = symbiosis Keywords = nodulation Keywords = rhizobium Keywords = defense Keywords = ANOVA Keywords = plant Keywords: nodulating vs not nodulating
Project description:Soybean root hair transcriptional response to their inoculation by the symbiotic bacteria B. japonicum involved in soybean nodulation. We used the first generation of an Affymetrix microarray to quantify the abundance of the transcripts from soybean root hair cells inoculated and mock-inoculated by B. japonicum. This experiment was performed on a time-course from 6 to 48 hours after inoculation.
Project description:Global bottom-up proteomics analysis of proteins purified from soybean root nodules infected with either WT or nifH- mutant Bradyrhizobium japonicum. Nine glycoproteins containing Lewis-a N-glycans, with 3 distinct Lewis-a epitopes (Hex:5 HexNAc:4 dHex:3 Pent:1, Hex:4 HexNAc:4 dHex:2 Pent:1, and Hex:4 HexNAc:3 dHex:2 Pent:1) were observed. Proteins purified from WT and nifH- infected soybean root nodules (five biological replicates each) were reduced using dithiothreitol, alkylated with iodoacetamide and trypsin digested followed by C18 SPE clean-up and LC-MS/MS analysis. Raw data files were processed using FragPipe v17.1, then output files 'combined_modified_peptide.tsv' and 'combined_protein.tsv' were used to identify glycopeptides and for global protein quantitation. These files, along with Excel files containing global quantitation analysis files for soybean nodule (Glycine max) and bacterial (Bradyrhizobium), are available in directory 'Quantification/MSFragger_results'. Glycopeptide data were also processed with PMI Byonic, and Excel file results are available in directory 'Quantification/PMI_Byonic_results'.
Project description:Soybean root hair transcriptional response to their inoculation by the symbiotic bacteria B. japonicum involved in soybean nodulation. We used the first generation of an Affymetrix microarray to quantify the abundance of the transcripts from soybean root hair cells inoculated and mock-inoculated by B. japonicum. This experiment was performed on a time-course from 6 to 48 hours after inoculation. Soybean seeds were sowed on sterile agar medium and grown for 3 days in a growth chamber before being treated with H2O (mock-inoculated) or B. japonicum (inoculated). Soybean root hair cells were isolated at different time points (6hr, 12hr, 18hr, 24hr, 36hr, 48hr) after treatment. For each time point and condition, 3 or 4 independent biological replicates were produced.
Project description:Expression data from B. japonicum soybean root nodules including a nodulation time-course experiment with soybean nodules harvested at 10, 13, 21 and 31 dpi and transcriptome of bacteroids formed by a mutant defective in the RNA polymerase transcription factor sigma 54. Two reference data sets were established using B. japonicum cells grown in PSY medium under either aerobic or micro-aerobic conditions. Keywords: genetic modification, time course, growth conditions
Project description:Elevated atmospheric CO2 can influence the structure and function of rhizosphere microorganisms by altering root growth and the quality and quantity of compounds released into the rhizosphere via root exudation. In these studies we investigated the transcriptional responses of Bradyrhizobium japonicum cells growing in the rhizosphere of soybean plants exposed to elevated atmospheric CO2. Transciptomic expression profiles indicated that genes involved in carbon/nitrogen metabolism, and FixK2-associated genes, including those involved in nitrogen fixation, microanaerobic respiration, respiratory nitrite reductase, and heme biosynthesis, were significantly up-regulated under conditions of elevated CO2, relative to plants and bacteria grown under ambient CO2 growth conditions. The expression profile of genes involved in lipochitinoligosaccharide Nod factor biosynthesis and negative transcriptional regulators of nodulation genes, nolA and nodD2, were also influenced by plant growth under conditions of elevated CO2. Taken together, results of these studies indicate that growth of soybeans under conditions of elevated atmospheric CO2 influences gene expressions in B. japonicum in the soybean rhizosphere, resulting in changes to carbon/nitrogen metabolism, respiration, and nodulation efficiency. Bradyrhizobium japonicum strains were grown in the soybean rhizosphere under two different CO2 concentrations. Transcriptional profiling of B. japonicum was compared between cells grown under elevated CO2 and ambient conditions. Four biological replicates of each treatment were prepared, and four microarray slides were used for each strain.
Project description:Elevated atmospheric CO2 can influence the structure and function of rhizosphere microorganisms by altering root growth and the quality and quantity of compounds released into the rhizosphere via root exudation. In these studies we investigated the transcriptional responses of Bradyrhizobium japonicum cells growing in the rhizosphere of soybean plants exposed to elevated atmospheric CO2. The results of microarray analyses indicated that atmospheric elevated CO2 concentration indirectly influences on expression of large number of Bradyrhizobium genes through soybean roots. In addition, genes involved in C1 metabolism, denitrification and FixK2-associated genes, including those involved in nitrogen fixation, microanaerobic respiration, respiratory nitrite reductase, and heme biosynthesis, were significantly up-regulated under conditions of elevated CO2 in the rhizosphere, relative to plants and bacteria grown under ambient CO2 growth conditions. The expression profile of genes involved in lipochitinoligosaccharide Nod factor biosynthesis and negative transcriptional regulators of nodulation genes, nolA and nodD2, were also influenced by plant growth under conditions of elevated CO2. Taken together, results of these studies indicate that growth of soybeans under conditions of elevated atmospheric CO2 influences gene expressions in B. japonicum in the soybean rhizosphere, resulting in changes to carbon/nitrogen metabolism, respiration, and nodulation efficiency.
Project description:Lipo-chitooligosaccharides (LCOs) produced by N2-fixing rhizobacteria initiate host nodule formation. Foliar application of LCOs has been shown to induce stress-related genes under optimal growth conditions. To study the effects of LCO foliar spray under stressed conditions, soybean seedlings grown at optimal temperature were exposed to sub-optimal temperature. After a 5-day acclimation period, the first trifoliolate leaves were sprayed with 10-7 M LCO (NodBj-V (C18:1, MeFuc)) produced by Bradyrhizobium japonicum, and harvested at 0 and 48 h following treatment. Microarray analysis was performed using Affymetrix GeneChip® Soybean Genome Arrays. A total of 147 genes were differentially expressed 48 h after LCO treatment, including a number of stress-related genes and transcription factors. In addition, during the 48 h following treatment, hundreds of genes were differentially expressed in LCO-treated plants, indicating that the dynamic soybean foliar transcriptome was highly responsive to LCO treatment. The microarray data was supported by quantitative real-time PCR data. Soybean seedlings grown at optimal temperature (25 °C) were exposed to sub-optimal temperature (15 °C). After a 5-day acclimation period, the first trifoliolate leaves were sprayed with 10-7 M LCO (NodBj-V (C18:1, MeFuc)) produced by Bradyrhizobium japonicum, and harvested at 0 and 48 h following treatment. Total RNA was extracted and microarray analysis was performed using Affymetrix GeneChip® Soybean Genome Arrays.
Project description:Lipo-chitooligosaccharides (LCOs) produced by N2-fixing rhizobacteria initiate host nodule formation. Foliar application of LCOs has been shown to induce stress-related genes under optimal growth conditions. To study the effects of LCO foliar spray under stressed conditions, soybean seedlings grown at optimal temperature were exposed to sub-optimal temperature. After a 5-day acclimation period, the first trifoliolate leaves were sprayed with 10-7 M LCO (NodBj-V (C18:1, MeFuc)) produced by Bradyrhizobium japonicum, and harvested at 0 and 48 h following treatment. Microarray analysis was performed using Affymetrix GeneChip® Soybean Genome Arrays. A total of 147 genes were differentially expressed 48 h after LCO treatment, including a number of stress-related genes and transcription factors. In addition, during the 48 h following treatment, hundreds of genes were differentially expressed in LCO-treated plants, indicating that the dynamic soybean foliar transcriptome was highly responsive to LCO treatment. The microarray data was supported by quantitative real-time PCR data.