Search results for "MEDICAGO"
showing 10 items of 107 documents
TheMedicago truncatulahypermycorrhizal B9 mutant displays an altered response to phosphate and is more susceptible toAphanomyces euteiches
2014
Inorganic phosphate (Pi) plays a key role in the development of arbuscular mycorrhizal (AM) symbiosis, which is favoured when Pi is limiting in the environment. We have characterized the Medicago truncatula hypermycorrhizal B9 mutant for its response to limiting (P/10) and replete (P2) Pi. On P2, mycorrhization was significantly higher in B9 plants than in wild-type (WT). The B9 mutant displayed hallmarks of Pi-limited plants, including higher levels of anthocyanins and lower concentrations of Pi in shoots than WT plants. Transcriptome analyses of roots of WT and B9 plants cultivated on P2 or on P/10 confirmed the Pi-limited profile of the mutant on P2 and highlighted its altered response t…
Etude de la régulation du facteur de transcription ATB2 chez Medicago truncatula
2013
Rapport de stage de Master 2 Spécialité Biologie Intégrative des Interactions Plantes, Microbes, Environnement BAP GEAPSI; Master; Climatic changes since more than a century combined with the urge for better crop yields due to a huge demographic growth and coupled with the need for a more sustainable agriculture led to a number of stresses for plants. Understanding them and their effect on growth, seed quality and seed production of plants is one of the most important agronomical issues of our time. We have chosen to study legumes because they are a major lipid and protein source, as both food and feed, and for their unique ability to absorb the atmospheric nitrogen via a symbiosis with Rhi…
Effet de la nutrition et du génotype sur les réponses de défense chez Medicago truncatula
2014
Les organismes phytopathogènes sont responsables de la destruction d’environ 30% des récoltes. Malgré leur impact négatif sur l’environnement et la santé humaine, les produits phytosanitaires restent un des principaux moyens de lutte. Dans un cadre général de diminution de l’utilisation de ces produits, mon projet de thèse a pour objectif de mieux comprendre l’effet de la nutrition de la plante et de son génotype sur les mécanismes moléculaires impliqués dans ses réponses de défense vis-à-vis des pathogènes et ceci afin de définir des stratégies de lutte innovantes. Etude de l’effet des carences nutritionnelle sur la signalisation cellulaire et moléculaire des réponses de défense par analys…
Different Medicago truncatula genotypes, expressing different phenotypes, modulate microbial functional genes in the rhizosphere
2022
Plants host in their rhizosphere a remarkable diversity of microorganisms that in return promote plant growth and health. Thus, the plant microbiota emerges as a novel component that expand the capacity of plants to adapt to the environment, and thus pave the way for future breeding approaches.It is widely known that different plant species harbor different microbiota, but very few studies showed an impact of the plant genotypes on the microbiota. These contrasting results may depend on the choice of the tested genotypes.We formulate the hypothesis that only those plant genotypes showing high genetic diversity and expressing different phenotypes harbor different rhizosphere microbiota and a…
Interaction between Medicago truncatula and Pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric CO2.
2012
10 pages; International audience; Soil microorganisms play a key role in both plants nutrition and health. Their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. These interactions involved the liberation of plant organic compounds via rhizodeposition. Modification of atmospheric CO2 concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. Positive effect of elevated CO2 on plants are rather well known but consequences for micoorganisms and their interactions with plants are still poorly understood. A gnotobiotic system has been devel…
Mtha1, a Plasma Membrane H+-ATPase Gene fromMedicago truncatula,Shows Arbuscule-Specific Induced Expression in Mycorrhizal Tissue
2002
: Transport processes between plant and fungal cells are key elements in arbuscular mycorrhiza (AM), where H+-ATPases are considered to be involved in active uptake of nutrients from the symbiotic interface. Genes encoding H+-ATPases were identified in the genome of Medicago truncatula and three cDNA fragments of the H+-ATPase gene family (Mtha1 - 3) were obtained by RT-PCR using RNA from M. truncatula mycorrhizal roots as template. While Mtha2 and Mtha3 appeared to be constitutively expressed in roots and unaffected by AM development, transcripts of Mtha1 could only be detected in AM tissues and not in controls. Further analyses by RT-PCR revealed that Mtha1 transcripts are not detectable …
Partial Sequence Homogenization in the 5S Multigene Families May Generate Sequence Chimeras and Spurious Results in Phylogenetic Reconstructions
2014
Multigene families have provided opportunities for evolutionary biologists to assess molecular evolution processes and phylogenetic reconstructions at deep and shallow systematic levels. However, the use of these markers is not free of technical and analytical challenges. Many evolutionary studies that used the nuclear 5S rDNA gene family rarely used contiguous 5S coding sequences due to the routine use of head-to-tail polymerase chain reaction primers that are anchored to the coding region. Moreover, the 5S coding sequences have been concatenated with independent, adjacent gene units in many studies, creating simulated chimeric genes as the raw data for evolutionary analysis. This practice…
Unravelling the determinants of freezing tolerance in Medicago truncatula: a first step towards improving the response of crop legumes to freezing st…
2020
International audience; Freezing is a major environmental limitation that affects biomass and seed productivity in a large number of crop species including legumes. Medicago truncatula is a model molecular‐genetic system for legume biology. A strategy to decipher freezing tolerance after a cold acclimation period in M. truncatula was developed using a quantitative genetic approach. Three main quantitative trait loci (QTL) with additive effects for freezing damage were detected on chromosomes 1, 4, and 6 using a recombinant inbred line population derived from a cross between the freezing‐tolerant accession F83005‐5 and the freezing‐sensitive accession DZA045‐5. The QTL on chromosome 6, named…
Construction and validation of cDNA-based Mt6k-RIT macro- and microarrays to explore root endosymbioses in the model legume Medicago truncatula
2004
To construct macro- and microarray tools suitable for expression profiling in root endosymbioses of the model legume Medicago truncatula, we PCR-amplified a total of 6048 cDNA probes representing genes expressed in uninfected roots, mycorrhizal roots and young root nodules [Nucleic Acids Res. 30 (2002) 5579]. Including additional probes for either tissue-specific or constitutively expressed control genes, 5651 successfully amplified gene-specific probes were used to grid macro- and to spot microarrays designated Mt6k-RIT (M. truncatula 6k root interaction transcriptome). Subsequent to a technical validation of microarray printing, we performed two pilot expression profiling experiments usin…
Amplification, contraction and genomic spread of a satellite DNA family (E180) in Medicago (Fabaceae) and allied genera
2011
†Background and Aims Satellite DNA is a genomic component present in virtually all eukaryotic organisms. The turnover of highly repetitive satellite DNA is an important element in genome organization and evolution in plants. Here we assess the presence and physical distribution of the repetitive DNA E180 family in Medicago and allied genera. Our goals were to gain insight into the karyotype evolution of Medicago using satellite DNA markers, and to evaluate the taxonomic and phylogenetic signal of a satellite DNA family in a genus hypothesized to have a complex evolutionary history. †Methods Seventy accessions from Medicago, Trigonella, Melilotus and Trifolium were analysed by PCR to assess …