Poplar root exudates response to multi-nutrients stress
In the face of global changes, agroecosystem productivity is essential both for CO2 fixation and feeding the increasing population. However, plant growth is frequently limited by nutrient availability and in the environment, plants are more often exposed to multiple than single nutrient deficiencies. Plant responses to single nutrient deficiencies have been widely studied while the combined effect of different nutrient deficiencies has been scarcely investigated, particularly for tree species. Root exudates comprise a complex mixture of organic compounds, directly involved in the biogeochemical cycles of nutrients in soils, it can be assumed that their quantity and quality are affected by combined nutrient deficiencies in a different way than under a single one. Thus, this proposal aims to profile Poplar (a fast-growing tree) root exudates under single and combined deficiencies, mainly focusing on: (1) N for macronutrient deficiency as the most often limiting nutrient and on Fe, Zn, and Mn as micronutrients because of their crucial role in photosynthesis, (2) experiments on mineral deficient calcareous soils close to agronomical situations and (3) testing the potential of Poplar root exudates to alleviate nutrient deficiencies in sensitive species such as fruit trees growing on  calcareous soils. The applicant has a very strong background in soil chemistry and plant nutrition acquired during her MSc and Ph.D., which together with the experience and facilities of the host and the international supervisory team will lead to the successful completion of this project and the strengthening of the career development of the researcher. The interdisciplinary work involving plant physiology, metabolite profiling, and chemoinformatic tools will lead to (1) improve knowledge about root exudation under nutritional stress and (2) open a new perspective on root-root interactions that can improve plant nutrition.