Search results for " Mycorrhiza"
showing 10 items of 178 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…
Influence of plant traits, soil microbial properties, and abiotic parameters on nitrogen turnover of grassland ecosystems
2016
International audience; Although it is known that multiple interactions among plant functional traits, microbial properties , and abiotic soil parameters influence the nutrient turnover, the relative contribution of each of these groups of variables is poorly understood. We manipulated grassland plant functional composition and soil nitrogen (N) availability in a multisite mesocosm experiment to quantify their relative effects on soil N turnover. Overall, root traits, arbuscular mycorrhizal colonization, denitrification potential, as well as N availability and water availability, best explained the variation in measured ecosystem properties, especially the trade-off between nutrient sequest…
Acaulospora sieverdingii, an ecologically diverse new fungus in the Glomeromycota, described from lowland temperate Europe and tropical West Africa
2011
International audience; From a survey of arbuscular mycorrhizal (AM) fungi in agro-ecosystems in Central Europe and West Africa, an undescribed species of Acaulospora was recovered and is presented here under the epithet Acaulospora sieverdingii. Spores of A. sieverdingii are 60-80 mu m in diam, hyaline to subhyaline to rarely light yellow and have multiple pitted depressions on the outer spore wall similar to those known for A. alpina, A. cavernata, A. paulinae and A. scrobiculata. The pits in A. sieverdingii are tiny and often irregular and resemble small dots (0.8-1.8 mu m) or lines (0.5-1.2 x 1.8-2.5 mu m). Analyses of the ITS1, 5.8S subunit and ITS2 regions of the rDNA resolved each of…
Services provided by soil microorganisms to improve plant phosphate nutrition
2022
Since the first Green Revolution, agricultural practices have been based on the massive use of synthetic fertilisers and plant protection products. Since then, global consumption of phosphate fertilisers has more than tripled, reaching 47 million tonnes in 2019. Current projections estimate that phosphate rock stocks (natural phosphorus resources for fertiliser production) could be depleted within the next century, leading us to change our agricultural practices. In soils, P is mainly present in complexed forms that are not easily accessible to plants. To reduce the use of phosphate fertilisers, it is necessary to make this complexed phosphate accessible to plants. This can be done by benef…
Arbuscular mycorrhiza - studies on the geosiphon symbiosis lead to the characterization of the first glomeromycotan sugar transporter
2007
Article Addendum ; International audience; The intimate arbuscular mycorrhiza (AM) association between roots and obligate symbiotic Glomeromycota (‘AM fungi’) ‘feeds’ about 80% of land plants. AM forming fungi supply land plants with inorganic nutrients and have an enormous impact on terrestrial ecosystems. In return, AM fungi obtain up to 20% of the plant‑fixed CO2, putatively as monosaccharides. In a recent work we have reported the characterization of the first glomeromycotan monosaccharide transporter, GpMST1, and its gene sequence. We discuss that AM fungi might take up sugars deriving from plant cell‑wall material. The GpMST1 sequence delivers valuable data for the isolation of orthol…
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 …
Glomeromycotina: what is a species and why should we care?
2018
International audience; A workshop at the recent International Conference on Mycorrhiza was focused on species recognition in Glomeromycotina and parts of their basic biology that define species. The workshop was motivated by the paradigm-shifting evidence derived from genomic data for sex and for the lack of heterokaryosis, and by published exchanges in Science that were based on different species concepts and have led to differing views of dispersal and endemism in these fungi. Although a lively discussion ensued, there was general agreement that species recognition in the group is in need of more attention, and that many basic assumptions about the biology of these important fungi includ…
Managing arbuscular mycorrhizal fungi in cropping systems
2005
Market globalization, demographic pressure, and environmental degradation have led us to reconsider many of our current agricultural systems. The heavy use of chemical inputs, including fertilizers and pesticides, has resulted in pollution, decreased biodiversity in intensively-farmed regions, degradation of fragile agro-ecosystems, and prohibitive costs for many farmers. Low input sustainable cropping systems should replace conventional agriculture, but this requires a more comprehensive understanding of the biological interactions within agro-ecosystems. Mycorrhizal fungi appear to be the most important telluric organisms to consider. Mycorrhizae, which result from a symbiosis between th…
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…
Mitochondrial genotyping of isolates of the arbuscular mycorrhizal fungus "Glomus intraradices" from the isolate collection of the International Bank…
2011
International audience; The culture collection of the International Bank of Glomeromycota (BEG) provides an important service to scientific community and industry by acting as a repository for well-defined AMF isolates which are made available to the public. The most widely-used species has been referred to as "Glomus intraradices", and was recently renamed Rhizophagus irregularis. This species has emerged as a model organism for experimental research and is the subject of the first AMF genome to be sequenced. The only genetic marker that can currently be used to distinguish strains of R. irregularis in field settings is the mitochondrial large subunit (mtLSU). In addition, genetically dist…