Site climate more than soil properties and topography shape the natural arbuscular mycorrhizal symbiosis in maize and spore density within rainfed maize (Zea mays L.) cropland in the eastern DR Congo.

Rhizosphere microorganisms, particularly arbuscular mycorrhizal fungi (AMF), play a vital role in enhancing sustainable maize production. However, uncertainty persist regarding the influence of climate variables and soil properties on mycorrhizal colonization (MC) of maize and the abundance of AM fungal spores in the field. This study aimed to explore the environmental factors such as site climate variables, soil physicochemical properties and topography and vegetation variable, affecting the natural MC of maize and the density of AMF spores.

Development of on-farm AMF inoculum production for sustainable agriculture in Senegal.

The integration of endomycorrhizal fungi into agricultural practices as inoculum offers the potential to improve plant productivity while reducing reliance on expensive chemical fertilizers, which are not only economically costly but also detrimental to the environment. Mycorrhizal fungi play a crucial role in facilitating plant access to essential mineral elements (such as Phosphorus, Potassium, etc.) and water, particularly in soils characterized by arid and semi-arid conditions.

Mycorrhizal inoculation and fertilizer microdosing interactions in pearl millet () under greenhouse conditions.

Introduction: Soil fertility is a major constraint to agricultural development in the Sahel region of Africa. One alternative to reducing the use of mineral fertilizers is to partially replace them with microbes that promote nutrition and growth, such as arbuscular mycorrhizal fungi (AMF). Mineral fertilizer microdosing is a technique developed to enhance fertilizer efficiency and encourage smallholder farmers to adopt higher mineral fertilizer applications.

Setting up Agrobacterium tumefaciens-mediated transformation of the tropical legume Aeschynomene evenia, a powerful tool for studying gene function in Nod Factor-independent symbiosis.

Most legumes are able to develop a root nodule symbiosis in association with proteobacteria collectively called rhizobia. Among them, the tropical species Aeschynomene evenia has the remarkable property of being nodulated by photosynthetic Rhizobia without the intervention of Nod Factors (NodF). Thereby, A.

Rice developmental stages modulate rhizosphere bacteria and archaea co-occurrence and sensitivity to long-term inorganic fertilization in a West African Sahelian agro-ecosystem.

Background: Rhizosphere microbial communities are important components of the soil-plant continuum in paddy field ecosystems. These rhizosphere communities contribute to nutrient cycling and rice productivity. The use of fertilizers is a common agricultural practice in rice paddy fields.

Mapping of QTLs Associated with Biological Nitrogen Fixation Traits in Peanuts ( L.) Using an Interspecific Population Derived from the Cross between the Cultivated Species and Its Wild Ancestors.

Peanuts ( L.) are an allotetraploid grain legume mainly cultivated by poor farmers in Africa, in degraded soil and with low input systems. Further understanding nodulation genetic mechanisms could be a relevant option to facilitate the improvement of yield and lift up soil without synthetic fertilizers.

Genetic control of rhizosheath formation in pearl millet.

The rhizosheath, the layer of soil that adheres strongly to roots, influences water and nutrients acquisition. Pearl millet is a cereal crop that plays a major role for food security in arid regions of sub-Saharan Africa and India. We previously showed that root-adhering soil mass is a heritable trait in pearl millet and that it correlates with changes in rhizosphere microbiota structure and functions.

Cultivated and wild pearl millet display contrasting patterns of abundance and co-occurrence in their root mycobiome.

Fungal communities associated with roots play a key role in nutrient uptake and in mitigating the abiotic and biotic stress of their host. In this study, we characterized the roots mycobiome of wild and cultivated pearl millet [Pennisetum glaucum (L.) R.

Changes in Intraspecific Diversity of the Arbuscular Mycorrhizal Community Involved in Plant-Plant Interactions Between Sporobolus robustus Kunth and Prosopis juliflora (Swartz) DC Along an Environmental Gradient.

The intensification of biological processes coping with salt stress became a major issue to mitigate land degradation. The Sine-Saloum Delta in Senegal is characterized by salt-affected soils with vegetation dominated by salt-tolerant grass Sporobolus robustus and shrubs like Prosopis juliflora. Plant experiments in controlled conditions suggested that arbuscular mycorrhizal (AM) fungi might be the key actors of facilitation process observed between S.

Potential Role and Utilization of Plant Growth Promoting Microbes in Plant Tissue Culture.

Plant growth promoting microbes (PGPMs) play major roles in diverse ecosystems, including atmospheric nitrogen fixation, water uptake, solubilization, and transport of minerals from the soil to the plant. Different PGPMs are proposed as biofertilizers, biostimulants, and/or biocontrol agents to improve plant growth and productivity and thereby to contribute to agricultural sustainability and food security. However, little information exists regarding the use of PGPMs in micropropagation such as the plant tissue culture.

Identification of type III effectors modulating the symbiotic properties of Bradyrhizobium vignae strain ORS3257 with various Vigna species.

The Bradyrhizobium vignae strain ORS3257 is an elite strain recommended for cowpea inoculation in Senegal. This strain was recently shown to establish symbioses on some Aeschynomene species using a cocktail of Type III effectors (T3Es) secreted by the T3SS machinery. In this study, using a collection of mutants in different T3Es genes, we sought to identify the effectors that modulate the symbiotic properties of ORS3257 in three Vigna species (V.

Exploiting Biological Nitrogen Fixation: A Route Towards a Sustainable Agriculture.

For all living organisms, nitrogen is an essential element, while being the most limiting in ecosystems and for crop production. Despite the significant contribution of synthetic fertilizers, nitrogen requirements for food production increase from year to year, while the overuse of agrochemicals compromise soil health and agricultural sustainability. One alternative to overcome this problem is biological nitrogen fixation (BNF).

From Isolation of Phosphate Solubilizing Microbes to Their Formulation and Use as Biofertilizers: Status and Needs.

The production of biofertilizers at industrial level is a bottleneck because bacterial strains are generally developed and managed by research laboratories and not by production units. A seamless transition from laboratory to field application is, therefore necessary. This review provides an overview of the constraints that limiting the application or the implementation of based biofertilizers especially in agricultural field and suggests solutions to overcome some of these limits.

Establishment of Actinorhizal Symbiosis in Response to Ethylene, Salicylic Acid, and Jasmonate.

Phytohormones play a crucial role in regulating plant developmental processes. Among them, ethylene and jasmonate are known to be involved in plant defense responses to a wide range of biotic stresses as their levels increase with pathogen infection. In addition, these two phytohormones have been shown to inhibit plant nodulation in legumes.

Complete Genome Sequence of sp. Strain ORS3257, an Efficient Nitrogen-Fixing Bacterium Isolated from Cowpea in Senegal.

Here, we report the complete genome sequence of Bradyrhizobium sp. strain ORS3257, which forms efficient symbioses with cowpea, peanut, or groundnut. These genomic data will be useful to identify genes associated with symbiotic performance and host compatibility on several legumes, including Aeschynomene species, with which a Nod-independent type III secretion system (T3SS)-dependent symbiosis can be established.

Actinorhizal Signaling Molecules: Root Hair Deforming Factor Shares Properties With NIN Inducing Factor.

Actinorhizal plants are able to establish a symbiotic relationship with bacteria leading to the formation of root nodules. The symbiotic interaction starts with the exchange of symbiotic signals in the soil between the plant and the bacteria. This molecular dialog involves signaling molecules that are responsible for the specific recognition of the plant host and its endosymbiont.

The rhizosphere of the halophytic grass Sporobolus robustus Kunth hosts rhizobium genospecies that are efficient on Prosopis juliflora (Sw.) DC and Vachellia seyal (Del.) P.J.H. Hurter seedlings.

The aim of this study was to survey the abundance and genetic diversity of legume-nodulating rhizobia (LNR) in the rhizosphere of a salt-tolerant grass, Sporobolus robustus Kunth, in the dry and rainy seasons along a salinity gradient, and to test their effectiveness on Prosopis juliflora (SW.) DC and Vachellia seyal (Del.) P.

Signalling in actinorhizal root nodule symbioses.

Plants able to establish a nitrogen-fixing root nodule symbiosis with the actinobacterium Frankia are called actinorhizal. These interactions lead to the formation of new root organs, called actinorhizal nodules, where the bacteria are hosted intracellularly and fix atmospheric nitrogen thus providing the plant with an almost unlimited source of nitrogen for its nutrition. Like other symbiotic interactions, actinorhizal nodulation involves elaborate signalling between both partners of the symbiosis, leading to specific recognition between the plant and its compatible microbial partner, its accommodation inside plant cells and the development of functional root nodules.

The plant-growth-promoting actinobacteria of the genus Nocardia induces root nodule formation in Casuarina glauca.

Actinorhizal plants form a symbiotic association with the nitrogen-fixing actinobacteria Frankia. These plants have important economic and ecological benefits including land reclamation, soil stabilization, and reforestation. Recently, many non-Frankia actinobacteria have been isolated from actinorhizal root nodules suggesting that they might contribute to nodulation.

Cell remodeling and subtilase gene expression in the actinorhizal plant Discaria trinervis highlight host orchestration of intercellular Frankia colonization.

Nitrogen-fixing filamentous Frankia colonize the root tissues of its actinorhizal host Discaria trinervis via an exclusively intercellular pathway. Here we present studies aimed at uncovering mechanisms associated with this little-researched mode of root entry, and in particular the extent to which the host plant is an active partner during this process. Detailed characterization of the expression patterns of infection-associated actinorhizal host genes has provided valuable tools to identify intercellular infection sites, thus allowing in vivo confocal microscopic studies of the early stages of Frankia colonization.

Permanent Draft Genome Sequences for sp. Strains LCM 4576, LCM 4577, and ORS3428, Salt-Tolerant, Nitrogen-Fixing Bacteria Isolated from Senegalese Soils.

The genus contains many species that are able to form nitrogen-fixing nodules on plants of the legume family. Here, we report the draft genome sequences for three strains. The genome sizes of strains LCM 4576, LCM 4577, and ORS3428 were 7.

Pearl Millet Genome: Lessons from a Tough Crop.

Pearl millet is an important cereal for food security in the arid regions of Africa and India. The recently published genome of this tough cereal crop has shed new light on its history and adaptation to dry, hot climates and paves the way for much-needed genomic-based breeding efforts.