Project description:Root nodule microbial communities from Medicago polymorpha collected in Santa Monica, California, United States - brown nodules metagenome
Project description:Root nodule microbial communities from Medicago polymorpha collected in Santa Monica, California, United States - pink nodules metagenome
Project description:Medicago polymorpha root nodule microbial communities from Los Angeles, California, United States - branched nodules metagenome
| PRJNA539521 | ENA
Project description:EMG produced TPA metagenomics assembly of PRJNA539517 data set (Root nodule microbial communities collected in Santa Monica, California, United States - Edamame nodules 1 metagenome).
Project description:Nitrogen assimilation in plants is a tightly regulated process that integrates developmental and environmental signals. The legume-rhizobial symbiosis results in the formation of a specialized organ called root nodule, where the rhizobia fixes atmospheric nitrogen into ammonia. Ammonia is assimilated by the plant enzyme glutamine synthetase, which is specifically inhibited by PPT. The expression of key genes related to the regulation of root nodule metabolism will likely be affected by glutamine synthetase inhibition. We used microarrays to detail the global programme of gene expression in response to Glutamine synthetase inhibition in root nodules and identified genes differentially expressed over a time course. Medicago truncatula nodulated plants (20 days post inoculation) were treated with 0.25 mM of PPT. Root nodules were harvested at 4, 8 and 24 hours after PPT application. As a control, root nodules collected just before PPT application were used (PPT 0h). Three biological replicates consisting of pools of root nodules harvested from five distinct plants were used for RNA extraction and hybridization on Affymetrix GeneChips.
Project description:12plex_medicago_2014_02 - nar nodule vs root transcriptome - which are the genes differentially expressed in alfalfa spontaneous (non rhizobium-infected) nodules vs. control roots? - biological material: aeroponically grown cuttings of a Medicago sativa (alfalfa) accession that produces empty nodules when nitrogen-starved. Samples for transcriptome comparison: isolated NAR nodules (10 days post N-starvation) vs. roots of the same plants (pools of 3 roots).
Project description:Legumes perform symbiotic nitrogen fixation through rhizobial bacteroids housed in specialised root nodules. The biochemical process is energy‐intensive and consumes a huge carbon source to generate sufficient reducing power. To maintain the symbiosis, malate is supplied by legume nodules to bacteroids as their major carbon and energy source in return for ammonium ions and nitrogenous compounds. To sustain the carbon supply to bacteroids, nodule cells undergo drastic reorganisation of carbon metabolism. Here, a comprehensive quantitative comparison of the mitochondrial proteomes between root nodules and uninoculated roots was performed using data‐independent acquisition proteomics, revealing the modulations in nodule mitochondrial proteins and pathways in response to carbon reallocation. Corroborated our findings with that from the literature, we believe nodules preferably allocate cytosolic phosphoenolpyruvates towards malate synthesis in lieu of pyruvate synthesis, and nodule mitochondria prefer malate over pyruvate as the primary source of NADH for ATP production. Moreover, the differential regulation of respiratory chain‐associated proteins suggests that nodule mitochondria could enhance the efficiencies of complexes I and IV for ATP synthesis. This study highlighted a quantitative proteomic view of the mitochondrial adaptation in soybean nodules.
Project description:Metabolomics and transcriptomics of Bradyrhizobium diazoefficiens-induced root nodules Bradyrhizobium diazoefficiens is a nitrogen-fixing endosymbiont, which can grow inside root-nodule cells of the agriculturally important soybean and other host plants. Our previous studies described B. diazoefficiens host-specific global expression changes occurring during legume infection at the transcript and protein level. In order to further characterize nodule metabolism, we here determine by flow injection -time of flight mass spectrometry analysis the metabolome of i) nodules and roots from four different B. diazoefficiens host plants, ii) soybean nodules harvested at different time points during nodule development, and iii) soybean nodules infected by two strains mutated in key genes for nitrogen fixation, respectively. Ribose (soybean), tartaric acid (mungbean), hydroxybutanoyloxybutanoate (siratro) and catechol (cowpea) were among the metabolites found to be specifically elevated in one of the respective host plants. While the level of C4-dicarboxylic acids decreased during soybean nodule development, we observed an accumulation of trehalose-phosphate at 21 days post infection (dpi). Moreover, nodules from non-nitrogen-fixing bacteroids (nifA and nifH mutants) showed specific metabolic alterations; these were also supported by transcriptomics data that was generated for the two mutant strains and were helpful to separate for some examples the respective bacterial and plant contributions to the metabolic profile. The alterations included signs of nitrogen limitation in both mutants, and an increased level of a phytoalexin in nodules induced by the nifA mutant, suggesting that the tissue of these nodules exhibits defense and stress reactions.