Mercedes García Sánchez
AgreenSkills session, year: 2nd session, 2016
Receiving laboratory: Eco&Sol Functional Ecology & Soil Biogeochemistry, Montpellier
Country of origin : Czech Republic
Enhancing the mobilization of recalcitrant organic P by plants: is the microbial loop between P-mineralizing bacteria and their bacterial feeding-nematodes determinant to improve ecosystem functioning?
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 (myo-inositol hexakisphosphate) abundant in soil and some agricultural wastes. Unfortunately this P source is not used by plants unable to secrete enzymes – the phytases – required to release free phosphate, sole P form taken up by living cells. In contrast, some bacterial groups are able to release phytase. Therefore, increasing phytate-mineralizing bacterial populations through inoculation has been already studied but random effects on plant P nutrition were reported. The lack of bacterial grazers (nematodes) could explain these inconsistent results as recently shown (Irshad et al., 2012). Therefore, acting on the interactions between plants, bacteria and their grazers in the rhizosphere—the microbial loop— may dramatically enhance the cycling of phytate. 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, biophysics and chemical measurements. P use by three crops (tomato, durum wheat and chickpea) will be studied under different conditions (substrate availability, densities of inoculated bacteria and nematodes, nematofauna diversity) and related to the evolution of inoculated bacterial (using qRT-PCR and/or antibiotic- or GFP-reporter strains) and nematodes populations. In addition, 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 understanding which conditions are crucial for a positive effect of microbial loop on phytate use of crops.
I started my PhD studies at the Department of Soil Microbiology and Symbiotic of the Estación Experimental del Zaidín (EEZ-CSIC) in 2007. The topic of my PhD dissertation was the use of mycoremediated dry olive residue as suitable organic amendment to improve the crop production in combination with the inoculation of the arbuscular mycorrhizal fungi. I obtained my PhD in 2011, so then, I started my postdoctoral career working for a private company, Micelios del Sur, S.L., and my research activities were involved in the analysis of the quality of substrate for growing edible mushrooms. Thereafter, I obtained a fellowship at the Czech University of Life Sciences (Prague, Czech Republic) and I joined to the Department of Agro-Environmental Chemistry and Plant Nutrition. During this period, I obtained experience in the reclamation of degraded soils under different environmental scenarios using wastes material. To do it, I monitored the functionality, physiological diversity, composition and biomass of microbial communities. Summarizing, my main research activities are included in the soil functional ecology, soil biochemistry and plant nutrition. However, I´m also very concern on elucidate the role the role of plants and soil microorganisms in the functioning of agro/ecosystems and nutrients cycles, especially the Phosphorous (P) which is one of the most limiting nutrient in soil. Therefore, my AgreenSkills project is focused on enhancing the mobility of recalcitrant organic P forms through the interaction between a P-solubilizing bacteria and bacteria feeding nematodes.
1. García-Sánchez M*., Holeckova Z., Klouza M., Tlustos P., Szákova J 2016. Organic and inorganic amendment application on mercury-polluted soils: Effects on soil chemical and biochemical properties. Environmental Science and Pollution Research. 23:14254-14268. http://dx.DOI 10.1007/s11356-016-6591-7.
2. Száková J., Burešová A., Praus L., García-Sánchez M., Holečková Z., Gabriel J., Sysalová J., Červenka R., Komárek J., Grohová S., Tlustoš P 2016. The response of mercury (Hg) transformation in soil to sulfur and sulfur-rich biowaste application. Environmental Earth Sciences. 75: 584. http://dx.DOI 10.1007/s12665-016-5387-x.
3. García-Sánchez M*, Siles JA, Cajthaml T, García-Romera, Tlustos P, Száková J 2015. Effects of digestate and fly ash applications on soil functional properties and microbial communities. European Journal of Soil Biology, 71:1-12.
4. García-Sánchez M.*, García-Romera I, Cajthaml T, Tlustos P, Száková J 2015. Changes on soil microbial community functionality and structure of metal polluted site: effect of different digestate and fly-ash application. Journal of the Environmental Management, 162: 63-73.
5. García-Sánchez M., García-Romera I., Száková J., Kaplan L., Tlustos P 2015. The effectivity of various amendments to reduce the mobility of risk elements in multicontaminated soils. Environmental Science and Pollution Research. 18: 14325-14336. http://dx.DOI 10.1007/s11356-015-4678-1.
6. García-Sánchez M.*, Palma-Martínez J.M., García-Romera I., Aranda E. 2014. Arbuscular mycorrhizal symbiosis alleviates the oxidative stress induced by ADOR and enhancement the antioxidant response of tomato plants (Solanum lycopersicum L.). Journal of Plant Physiology 171: 421 – 428.
7. García-Sánchez, M., Paradiso, A., García-Romera, I., Aranda, E., de Pinto, M.C. 2014. Bioremediation of aqueous extract from dry olive mill residue removes inhibition of growth induced by this waste in tomato plants. International Journal of Environmental Science and Technology 11 (1)¬: 21-32.
8. Garrido I., García-Sánchez M., Casimiro I., Casero P.J., García-Romera I., Ocampo J.A., Espinosa F. 2012. Oxidative stress induced in sunflower seedling roots by aqueous dry olive mill-residue. PLos ONE 7(9): e46137. doi:10.1371/journal.pone.0046137.
9. García-Sánchez, M., Garrido, I., Casimiro, I., Casero, P.J., García-Romera I., Espinosa, F., Aranda, E. 2012. Defence response of tomato seedlings to oxidative stress induced by phenolic compounds from dry olive mill residue. Chemosphere 89: 708-716.
Sampedro, I., Aranda, E., Díaz, R., Siles, J.A., García-Sánchez, M., García-Romera, I., Ocampo, J.A. Method for increasing the production of a laccase of Coriolopsis rigida laccase using a biological inductor. REFERENCE NUMBER OF PUBLICATION: ES2365430. APPLICATION NUMBER: 201030417. DATE OF SUBMISSION: 23.03.2010. DATE OF AWARD: 14.01.2013. PRIORITY COUNTRY: España. HOLDER ENTITY: CSIC. ACCEPT.
Poster Awarded in the XVI International Biodeterioration and Biodegradation Symposium. Lodz (Poland), 2014: “García-Sánchez M., Sipkova A., Száková J., Kaplan L., Tlustos P. Digestate as an effective agent for mercury bioremediation”.