Project description:We used laser-capture microdissection (LCM) to isolate specific cells from the Medicago truncatula nodule meristem (M), the distal infection (DIZ), the proximal infection zone (PIZ), infected cells (IC) and uninfected cells (UIC) from the fixation zone. Based on Medicago GeneChips, we identified the cell- and tissue-specific programm of gene expression in Medicago truncatula root nodules.
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: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:We used laser-capture microdissection (LCM) to isolate specific cells from the Medicago truncatula nodule meristem (M), the distal infection (DIZ), the proximal infection zone (PIZ), infected cells (IC) and uninfected cells (UIC) from the fixation zone. Based on Medicago GeneChips, we identified the cell- and tissue-specific programm of gene expression in Medicago truncatula root nodules. Nodules were harvested three weeks after inoculation of Medicago truncatula (genotype Jemalong A17) plants with Sinorhizobium meliloti strain 2011. Nodules were fixed in Farmer's fixative and subsequently embedded in paraffin. 8 M-BM-5m de-paraffined sections were used to capture cells from the nodule meristem, distal infection zone, proximal infection zone, infected cells and uninfected cells from the fixation zone, using an Arcturus Pixcell II laser capture microscope. 3 biological replicates were used for each cell-/tissue type. After RNA extraction, the RNA was amplified and used for Medicago Gene Chip hybridization.
Project description:To understand the role of Medicago truncatula NODULE INCEPTION (MtNIN) in nodule development, we analyzed the transcriptome of roots ectopically overexpressing NIN, nodules of weak mutant allele nin-16, and nodules of dnf1-2 mutant.
Project description:We have used deep sequencing of small RNAs from nodules and root apexes of the model legume Medicago truncatula, to identify 113 novel candidate miRNAs. These miRNAs (legume or Mt-specific) are encoded by 278 putative hairpin precursors in the M. truncatula genome. Several miRNAs are differentially expressed in nodules and root tips and large variety of targets could be predicted for these genes. Specific miRNA isoforms showed contrasting expression patterns in these tissues Keywords: Transcriptome analysis
Project description:We have used deep sequencing of small RNAs from nodules and root apexes of the model legume Medicago truncatula, to identify 113 novel candidate miRNAs. These miRNAs (legume or Mt-specific) are encoded by 278 putative hairpin precursors in the M. truncatula genome. Several miRNAs are differentially expressed in nodules and root tips and large variety of targets could be predicted for these genes. Specific miRNA isoforms showed contrasting expression patterns in these tissues Keywords: Transcriptome analysis 3 samples examined: nodules, root tips, and root tips + NaCl
