Home page / Annual Meetings & Training / Annual Meetings / Annual Meeting 2018 / Fellows Speed Presentations / Enhancing the efficiency in the crop use P from soil phytate through the microbille loop.

Mercedes García Sánchez

Eco&Sol Functional Ecology & Soil Biogeochemistry, Montpellier

Enhancing the efficiency in the crop use P from soil phytate through the microbille loop.

Annual meeting: 2018

Fields-Topics: P3 Population and Ecosystems

Type of talk: Fellows Speed Presentation

Enhancing the efficiency in the crop use P from soil phytate through the microbille loop.


I started my research career at the laboratory of Biofertilization and Biodegradation by Rhizospheric Fungi which belongs to the Estación Experimental del Zaidín (EEZ-CSIC) located in Granada (Spain). During my PhD dissertation, I focused principally on issues regarding the suitability of the mycoremediated dry olive residue as organic amendment improving crop production in combination with the inoculation of the arbuscular mycorrhizal fungi. Later on, I joined at the Czech University of Life Sciences (Prague, Czech Republic) as postdoctoral researcher. The projects I have been involved in Prague were mainly concerned on the soil functional ecology, soil biochemistry and plant nutrition during the reclamation of degraded soils amended by organic/ inorganic materials. Currently, I am working at the INRA- Montpellier with Dr. Plassard as an AgreenSkills fellowship. My research subject is focused in the mobilization of organic phosphorous (P) forms, i.e. phytate since P is one of the most limiting nutrients for plants. With this project, I propose to investigate a microbial loop, based on the interaction between a P-solubilizing bacteria and their respective feeding nematodes, as a suitable strategy improving the phytate mineralization and enhancing its uptake by crops.


Enhancing the efficiency in the crop use P from soil phytate through the microbille loop.

Mineral P fertilisation to crops is heavily questioned because of the expected depletion of readily extractable phosphate mines. Finding alternative P sources for crops is therefore urgent. A promising solution is to enhance the use of organic P such as phytate abundant in soil and some agricultural wastes. Previous studies, conducted at the hosting lab, have observed how the interactions between plants, bacteria and their grazers in the rhizosphere - the microbial loop - may dramatically enhance the cycling of phytate. Therefore, the present project aims at understanding the mechanisms determining the role of the microbial loop on plant phytate use, looking at the effects of biological and physico-chemical conditions on Pi release from phytate, the evolution of bacterial and nematode populations and their interactions by a combination of biological methods, bacterial genetics, and biochemical measurements. P use by three crops (tomato, durum wheat and chickpea) will be studied under different conditions: i) substrate availability, ii) densities of inoculated bacteria, iii) nematodes, nematofauna diversity, and iv) related to the evolution of inoculated bacterial (GFP-reporter strains) and nematodes populations. Moreover, in this project, we will collaborate with Leyla Slamti (Researcher at Micalis) to produce the GFP-labeled bacteria. Likewise, the effect of nematodes on phytate use through their own phytase and/or by their capacity to disperse bacterial populations will be assessed. This knowledge will help us for understanding which conditions are crucial for a positive effect of microbial loop on phytate use of crops.

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