P11 - Exudate Dynamics

The mystery of root exudation – new insights into ecologically significant root exudation sampling


Root exudates (i.e. primary & secondary metabolites released by roots) are key drivers of plant-microbe-soil interactions. In the past, root exudation was mostly studied in nutrient solution culture (hydroponic). Despite the operational benefit of hydroponics, the question remains how ecologically relevant exudation results obtained under hydroponic conditions are compared to soil environments.
In phase 1, we characterized maize root exudation in the two, priority program 2089 specific, experimental platforms (SCE & SPE) and additionally evaluated the effect of different plant growth and exudation sampling approaches (soil vs hydroponic, lab vs field) demonstrating the importance of soil based exudation techniques, particularly in the context of plant-microbe-soil-interactions. In phase 2, we now set out to reveal the effect of soil environmental changes on maize (Zea mays WT & rth3) root exudation with particular focus on drought and changes in soil structural properties, which have both been identified as major factors driving rhizosphere pattern formation. In joint laboratory experiments with several other PP 2089 partners, we will reveal how root exudation of the two maize lines (WT, rth3) is altered upon moderate short-term as well as more severe long-term drought stress. We will also investigate seasonal differences in exudation in the field and evaluate a potential soil legacy effect induced by several years of maize monoculture. In addition, we will study modifications in maize exudation patterns upon soil structural changes, including soil compaction and changes in number of root-soil particle contact points under controlled conditions in the laboratory. Like in phase 1, we will focus on soil-based exudation sampling approaches and combine these ecological meaningful sampling techniques with non-targeted metabolomic analysis by UHPLC-QTOFMS and GC-QTOFMS to uncover the entire diversity of exudates released. Our results will provide important mechanistic insights on how root exudation is altered under changing environmental conditions. Furthermore, we will deliver key information for all exudation-driven rhizosphere processes that will be investigated by other participants within the PP 2098 und significantly contribute to merge individual parameter patterns and holistically decipher the spatiotemporal interplay of rhizosphere processes.

Link to English scientific abstract

Link to German scientific abstract