Comment le mode de nutrition azotée influence-t-il le prelèvement, le stokage et la remobilisation des nutriments en conditions hydriques fluctuantes chez le pois ?

Prod 2019-109f EA GEAPSI INRA DOCTNational audiencePea seeds have interesting nutritional properties through their protein, vitamin and mineral contents. However, environmental conditions such as soil water availability during plant growth influence both final yield and seed quality in pea. Soil water conditions not only modulates pea nitrogen acquisition whatever the mode of nitrogen nutrition: mineral nitrogen acquisition by roots and atmospheric di-nitrogen fixation by nodules in interaction with rhizobia, but also the overall plant mineral nutrition. The aim of this study is to get a better understanding of soil water deficit impact on nutrient acquisition, storage and distribution inside the plant according to the mode of nitrogen nutrition. In this study the first experimentation aims at characterizing 13 individual mineral deficiencies on nutrient uptake and remobilisation into different plant organs, allowing to design an ionomic fingerprint specific to each mineral deficiency. A second experimentation consists in implementing single (at vegetative or reproductive stage) or repeated water deficits to pea plants grown under both modes of nitrogen nutrition. This experimentation will allow us to analyse how water deficit influences nutrient uptake, storage and remobilisation via (1) ecophysiological analysis by using a structure-function framework including water and mineral fluxes at the whole plant level, (2) transcriptomic analysis of nodules and roots. We intend to identify the main regulatory genes involved in either single water deficit response or water deficit memory stress response. This study will allow us to provide new insights towards a better management of preventive or/and curative mineral fertilization solution in the field, in order to prevent pea from mineral deficiencies and improve its yield and seed quality under fluctuating water environment