Project description:Medicago truncatula engages in root nodule symbiosis by developing a de novo plant organ (known as nodule) in its roots in response to the infection by rhizobia. These nodules are de novo plant organs that provide an optimal environment for the rhizobia to fix nitrogen in exchange for photosynthates. The establishment of root nodule symbioses (RNS) requires the coordination of two distinct processes: bacterial infection and nodule organogenesis. In this study we used single-cell RNA-seq to investigate the first hours of the establishment of the root nodule symbiosis aiming to identify the transcriptional mechanisms governing this process.
Project description:Arbuscular mycorrhiza (AM) interactions between plants and Glomeromycota fungi primarily support phosphate aquisition of most terrestrial plant species. To unravel gene expression in Medicago truncatula root colonization by AM fungi, we used genome-wide transcriptome profiling based on whole mycorrhizal roots. We used GeneChips to detail the global programme of gene expression in response to colonization by arbuscular mycorrhizal fungi and in response to a treatment with phosphate and identified genes differentially expressed during this process.
Project description:Cytosine methylation is a base modification that is often used by genomes to store information that is stably inherited through mitotic cell divisions. Most cytosine DNA methylation is stable throughout different cell types or by exposure to different environmental conditions in plant genomes. Here, we profile the epigenomes of ~100 Medicago truncatula lines to explore the extent of natural epigenomic variation. We also use these data to determine the extent to which DNA methylation variants are linked to genetic variations.
Project description:Arbuscular mycorrhiza (AM) interactions between plants and Glomeromycota fungi primarily support phosphate aquisition of most terrestrial plant species. To unravel gene expression during early stages of Medicago truncatula root colonization by AM fungi, we used genome-wide transcriptome profiling based on mycorrhizal root fragments enriched for early fungal infection stages. We used Medicago GeneChips to detail the global programme of gene expression in response to early stages of colonization by arbuscular mycorrhizal fungi and identified genes differentially expressed during these early stages.
Project description:Plants show a remarkable plasticity to adapt their root architecture to biotic and abiotic constraints of the soil environment. Although some of these modifications are fine-tuned by miRNAs, there are still shadow zones in these regulations. In the model legume Medicago truncatula, we analyzed the small RNA (smRNA) transcriptome of roots submitted to symbiotic and pathogenic interactions. Mapping on the genome and prediction of pre-miRNA hairpins allowed the identification of 416 candidates. Out of them, we found known and novel variants of 77 miRNA families, already reported in miRBase. In addition, thanks stringent criteria of miRNA prediction, 53 mtr-miRNAs were discovered, including 27 putative miRtrons. Exploring polymorphism in 26 M. truncatula ecotypes, higher polymorphism was observed in conserved rather than legume-specific miRNA genes. An average of 19 targets, mainly involved in environmental responses and signaling, was predicted per novel miRNA. In addition, taking advantage of our large number of smRNA libraries, we identified sets of miRNAs responsive to root pathogens or to symbiotic interactions and the related Nod and myc-LCO signals.
Project description:Drought is one of the major environmental factors limiting biomass and seed yield production in agriculture. In this research we focused on plants from Fabaceae family, which have a unique ability for establishment of symbiosis with nitrogen-fixing bacteria, and are relatively susceptible to water limitation. We present the changes in nitrogenase activity and global gene expression occurring in Medicago truncatula and Lotus japonicus root nodules during water deficit. Our results prove a decrease in the efficiency of nitrogen fixation as well as extensive changes in plant and bacterial transcriptomes shortly after watering cessation. We show for the first time that not only symbiotic plant component, but also Sinorhizobium meliloti and Mesorhizobium loti bacteria residing in the root nodules of M. truncatula and L. japonicus, respectively, adjust their gene expression in response to water shortage. Although our results demonstrate that both M. truncatula and L. japonicus root nodules are susceptible to water deprivation, they indicate significant differences in plant and bacterial response to drought between tested species, which may be related to various type of root nodules formed by these species.
Project description:Molecular Elasticity and Adjustment of Drought Recovery Dynamics of 14N- and 15N-fertilized Legume Medicago truncatula. Climate change in conjunction with population growth necessitates a systems biology approach to characterize plant drought response and a more thorough understanding of the underlying molecular mechanisms. During drought stress and recovery, the metabolome and proteome regulate and are regulated through diverse mechanisms including synthesis and degradation. In order to study this complex regulation network, a front-end multilevel analysis is presented for the first time, investigating protein turnover, regulatory classes of proteins and metabolites as well as post translational ubiquitination of a target set of proteins during a severe stress and recovery scenario in the model legume Medicago truncatula. Evidence for enhanced translational proteome regulation was observed during drought recovery and functional clusters of differentially dynamic phases during the course of recovery were defined. The data give novel insights into molecular elasticity that enable recovery of drought stressed plants. Additionally, these results offer putative targets and metabolic pathways for future plant-bioengineering towards enhanced drought stress tolerance.
Project description:Plant species posses a special set of genes functional only in arbuscular mycorrhizal symbiosis. So, the model plant Medicago truncatula (Jemalong 5) was used for transcriptome comparative analysis while infected with compatible rhizobia Sinorhizobium meliloti (strain 10) and with or without arbuscular mycorrhizal fungus Rhizophagus irregularis (SYM5). Whole shoot and whole root were used for RNA isolation and processed via one of the European certified Affymetrix core labs (http://core.img.cas.cz).