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Processes at the soil-root interface shaping soil functions (Communication session)

EUROSOIL2020CONT-1990

THE MISSING LINK - UNRAVELLING METABOLITE DIVERSITY OF ROOT EXUDATES OF TWO DIFFERENT MAIZE GENOTYPES (ZEA MAYS) GROWN IN THE FIELD

Michael Santangeli^*^1,², Anna Heindl², Christina Hummel², Teresa Mairinger¹, Doris Vetterlein^3,⁴, Stephan Hann¹, Eva Oburger²

¹Department of Chemistry, Institute of Analytical Chemistry, Universität für Bodenkultur Wien, Vienna, ²Department of Forest and Soil Sciences, Institute of Soil Research, Universität für Bodenkultur Wien, Tulln an der Donau, Austria, ³Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, ⁴Department of Soil System Science, Helmholtz-Zentrum für Umweltforschung (UFZ), Halle/Saale, Germany

Content: Root exudates are a mixture of carbon (C) metabolites that are released by roots into the soil. Due to the importance of the exudate-driven rhizosphere processes, a detailed knowledge about quality and quantity of exudates released is thus a prerequisite for deciphering the complex biogeochemical processes in the rhizosphere. Unlike the majority of studies in the past, this work is focused on soil-based exudation sampling in the field. In this study we investigated root exudation of two different maize genotypes (Zea mays wild type and rth3, a naturally occurring root hairless mutant) grown on two soils differing in soil texture (Sand and Loam) at the experimental field station, Bad Lauchstädt, Germany. Coupling soil-based exudation sampling techniques applicable in the field with high-end metabolomic fingerprinting analysis allowed us to shed light into the complexity of C compounds released by the different maize genotypes. Our approach allowed us to obtain temporally resolved information about the metabolite patterns released by maize roots, providing key information on the complexity of root exudates and their interrelated rhizosphere processes.

Results show a significant effect for both soil and genotype on root and shoot biomass. The same applies to the total C exuded by the roots, where, additionally, a general decrease in C exudation rate in the later stages of plant growth was observed. Moreover, metabolomics results indicate the potential of our non-targeted analytical approach to reveal differences in released metabolite patterns. Results of this study will also contribute to elucidate the role of root hairs, as well as the influence of different soil types on maize root exudation and related rhizosphere patterns.

Disclosure of Interest: None Declared

Keywords: Carbon flow, Field experiment, Maize, Metabolomics, Rhizodeposition, Root exudates