Role of the AM interaction on S-uptake and S-starvation resistance in Medicago truncatula

Sulphur is an essential macronutrient for plant growth, development, and response to various abiotic and biotic stresses due to its key role in the biosynthesis of many S-containing compounds. Sulphate represents a very small portion of soil S pull and it’s the only form that plant roots can uptake and mobilize through H+-dependent co-transport processes implying sulphate transporters. Unlike the other organically bound forms of S, sulphate is normally leached from soils due to its solubility in water, thus reducing its availability to plants. Although our knowledge of plant sulphate transporters has been growing significantly in the last decades, little is still known about the effect of t…

The arbuscular mycorrhizal transportome, what next!

International audience; Understanding how arbuscular mycorrhizal (AM) symbioses establish and function is one of the most important current challenges in microbial ecology. Despite the fact that the AM symbiosis requires some complex and fine molecular tuning among symbionts in order to take place, both partners benefit from each other in a number of ways. For instance, the availability, uptake and exchange of nutrients in this biotrophic interaction are key factors driving plant growth and modulating biomass allocation. This underground trade is regulated by both plant and fungal transport components [1], as for instance the long distance transport of photosynthates from leaves towards col…

Sugar transporters in plants and in their interactions with fungi.

International audience; Sucrose and monosaccharide transporters mediate long distance transport of sugar from source to sink organs and constitute key components for carbon partitioning at the whole plant level and in interactions with fungi. Even if numerous families of plant sugar transporters are defined; efflux capacities, subcellular localization and association to membrane rafts have only been recently reported. On the fungal side, the investigation of sugar transport mechanisms in mutualistic and pathogenic interactions is now emerging. Here, we review the essential role of sugar transporters for distribution of carbohydrates inside plant cells, as well as for plant fungal interactio…

Identification of sugar transporters in arbuscular mycorrhiza, from basic to applied science

Our study focuses on sugar transporters from both plant and fungal partners at the symbiotic interface to better understand biotrophic exchange systems. Thereby, a collection of putative contigs and ESTs of hexose transporters from Medicago truncatula and Fragaria x ananassa will be processed. The full length sequences will be cloned for functional complementation and uptake experiments in transport deficient yeast mutants. This work also investigates the influence of different mycorrhizal fungi on (1) the expression level of sugar transporters and (2) the economically relevant part of F. x ananassa by analyzing its impact on the plant and the fruit. To this aim, combination of phenological…

Role of the arbuscular mycorrhizal symbiosis on S-uptake and S-starvation resistance in Medicago truncatula

Due to its key role in the biosynthesis of many S-containing compounds, sulphur is a macronutrient essential for plant growth, development, and response to various abiotic and biotic stresses. Sulphate represents a very small portion of soil S pull and it’s the only form that plant roots can take up and mobilize through H+-dependent co-transport processes implying sulphate transporters. Unlike the other organically bound forms of S, sulphate is normally leached from soils due to its solubility in water, thus reducing its availability to plants. Although our knowledge of plant sulphate transporters has been growing significantly in the last decades, little is still known about the effect of …

Transcriptional response of Medicago truncatula sulphate transporters to arbuscular mycorrhizal symbiosis with and without sulphur stress

Sulphur is an essential macronutrient for plant growth, development and response to various abiotic and biotic stresses due to its key role in the biosynthesis of many S-containing compounds. Sulphate represents a very small portion of soil S pull and it is the only form that plant roots can uptake and mobilize through H(+)-dependent co-transport processes implying sulphate transporters. Unlike the other organically bound forms of S, sulphate is normally leached from soils due to its solubility in water, thus reducing its availability to plants. Although our knowledge of plant sulphate transporters has been growing significantly in the past decades, little is still known about the effect of…

Champignons mycorhiziens et symbiose mycorhizienne, les as de la nutrition végétale

Prod 2018-228 SPE IPM INRA UB; National audience

Ammonium acts systemically while nitrate exerts an additional local effect on Medicago truncatula nodules

National audience; Symbiotic nitrogen fixation (SNF) has a high energetic cost for legume plants; legumes thus reduce SNF when soil N is available. The present study aimed to increase our understanding regarding the impacts of the two principal forms of available N in soils (ammonium and nitrate) on SNF. We continuously measured the SNF of Medicago truncatula under controlled conditions. This permitted nodule sampling for comparative transcriptome profiling at points connected to the nodules' reaction following ammonium or nitrate applications. The N component of both ions systemically induced a rhythmic pattern of SNF, while the activity in control plants remained constant. This rhythmic a…

Identification of sugar transporters in arbuscular mycorrhiza

Our study focuses on sugar transporters from both plant and fungal partners at the symbiotic interface to better understand biotrophic exchange systems. Thereby, a collection of putative contigs and ESTs of hexose transporters from Medicago truncatula and Fragaria x ananassa will be processed. The full length sequences will be cloned for functional complementation and uptake experiments in transport deficient yeast mutants. This work also investigates the influence of different mycorrhizal fungi on (1) the expression level of sugar transporters and (2) the economically relevant part of F. x ananassa by analyzing its impact on the plant and the fruit. To this aim, combination of phenological…

Rôle de la micorhize à arbuscules dans l'absoption et la résistance à la carence en soufre chez Medicago truncatula

International audience

Transcriptional responses of Medicago truncatula upon sulfur deficiency stress and arbuscular mycorrhizal symbiosis

International audience; Sulfur plays an essential role in plants' growth and development and in their response to various abiotic and biotic stresses despite its leachability and its very low abundance in the only form that plant roots can uptake (sulfate). It is part of amino acids, glutathione (GSH), thiols of proteins and peptides, membrane sulfolipids, cell walls and secondary products, so reduced availability can drastically alter plant growth and development. The nutritional benefits of symbiotic interactions can help the plant in case of S deficiency. In particular the arbuscular mycorrhizal (AM) interaction improves N, P and S plant nutrition, but the mechanisms behind these exchang…

Ressource exchanges in leguminous-gramineous associations: impact of multitrophic associations with beneficial microbes

International audience

Identification de transporteurs de sucres marqueurs de la mycorhize à arbuscules