Project description:A transcriptome of Cluster II Frankia in nitrogen-fixing root-nodule symbiosis with the host plant, Datisca glomerata, was obtained by Illumina sequencing and mapping to the corresponding published genome (NCBI Bioproject PRJNA46257). Major metabolic pathways detected in Cluster II Frankia in symbiosis with Datisca glomerata were comparable to those described as up-regulated in the Frankia alni-Alnus glutinosa symbiosis (N Alloisio et al, MPMI 23(5):593-607, 2010): nitrogenase biosynthesis, tricarboxylic acid cycle, respiratory-chain related functions, oxidation protection, and terpenoid biosynthesis. These functions are consistent with the primary activities of Frankia in root nodules, e.g. to carry out the energetically-demanding fixation of atmospheric dinitrogen to ammonium, and to maintain internal reducing conditions. Expression of genes coding for amino-acid biosynthetic pathways, including arginine as reported previously (AM Berry et al. Funct Plant Biol 38, 645–652, 2011) was detected. A striking difference from other Frankia strains, revealed in the transcriptome of the Cluster II Frankia in symbiosis, was the expression of homologs of rhizobial nodulation genes, nodA, nodB and nodC.
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:The actinobacteria Frankia alni is able to induce the formation of nodules on the root of a large spectrum of actinorhizal plants, where it converts dinitrogen to ammonia in exchange for plant photosynthates. In the present study, transcriptional analyses were performed on nitrogen-replete free-living cells and on Alnus glutinosa nodule bacteria, using whole genome microarrays. Distribution of nodule-induced genes on the genome was found to be mostly over regions with high synteny between three Frankia genomes, while nodule-repressed genes, which were mostly hypothetical and not conserved, were spread around the genome. Genes known to be related to symbiosis were highly induced: nif (nitrogenase), hup2 (hydrogenase uptake), suf (sulfur-iron cluster) and shc (hopanoids synthesis). The expression of genes involved in ammonium assimilation and transport was strongly modified suggesting that bacteria ammonium assimilation was limited. Genes involved in particular in transcriptional regulation, signalling processes, protein drug export, protein secretion, lipopolysaccharide and peptidoglycan biosynthesis that may play a role in symbiosis were also identified. We showed that this nodule transcriptome of Frankia was highly similar among phylogenetically distant plant families.
Project description:Purpose: To compare RNASeq data of Frankia CcI3 in plants under salt stress. Casuarina glauca root nodules infected with Frankia CcI3 were exposed to either no salt or 100 mM NaCl for 21 days. RNA-seq analysis provided insight into how the sybiont responds to salt stress.
Project description:In order to better understand the commonalities and differences in lateral root and nodule development, we compared their organogenesis and correlated this with changes in gene expression. To initiate lateral roots in Medicago truncatula we turned 2-day-old seedlings 135°, before returning them to their original axis of growth, while for nodule initiation we applied droplets of Sinorhizobium meliloti on the susceptibility zone of the root.
Project description:The actinobacteria Frankia alni is able to induce the formation of nodules on the root of a large spectrum of actinorhizal plants, where it converts dinitrogen to ammonia in exchange for plant photosynthates. In the present study, transcriptional analyses were performed on nitrogen-replete free-living cells and on Alnus glutinosa nodule bacteria, using whole genome microarrays. Distribution of nodule-induced genes on the genome was found to be mostly over regions with high synteny between three Frankia genomes, while nodule-repressed genes, which were mostly hypothetical and not conserved, were spread around the genome. Genes known to be related to symbiosis were highly induced: nif (nitrogenase), hup2 (hydrogenase uptake), suf (sulfur-iron cluster) and shc (hopanoids synthesis). The expression of genes involved in ammonium assimilation and transport was strongly modified suggesting that bacteria ammonium assimilation was limited. Genes involved in particular in transcriptional regulation, signalling processes, protein drug export, protein secretion, lipopolysaccharide and peptidoglycan biosynthesis that may play a role in symbiosis were also identified. We showed that this nodule transcriptome of Frankia was highly similar among phylogenetically distant plant families. To address gene expression changes of Frankia alni ACN in the symbiotic state, we compared transcript levels between young nodules formed on 4 species of trees (Alnus glutinosa, Alnus nepalensis, Myrica gale and Myrica rubra) and free-living cells grown in nitrogen-replete minimal medium. For A. glutinosa nodule and free-living cells, two sets of experiments (A and B) were performed in two different laboratories. Three biological replicates were preformed for each condition.