DARWIN

The DARWIN project addresses the critical need for sustainable agriculture. It aims to determine whether enhancing plant Nitrogen (N) uptake can be achieved through the artificial selection of rhizosphere microbiota, independently of the host plant selection. The core hypothesis is that artificial selection of the rhizosphere microbiota can modify plant phenotype (leaf N content) independently of plant genetics, offering a novel, dualoptimization strategy. The project uses maize lines from the Illinois Long-Term Selection Experiment exhibiting high or low grain protein content (IHP/ILP), which exhibit established differences in N uptake from a common genetic background. The work is divided into four Work Packages (WPs). WP1 aims at testing if N uptake differences in IHP and ILP lines are partially due to plant genes controlling microbiota recruitment. WP2 consists in an experiment with eight generations of artificial selection on rhizosphere microbiota for high and low N uptake on both IHP and ILP maize genotypes, to determine if the selection effects of plants and microbiota are independent or synergistic. WP3 aims at elucidating the mechanisms of the selected microbiota effect by quantifying N-cycle functional genes (qPCR) and directly measuring N fluxes (denitrification, N2 fixation and nitrification), testing if the effect involves differential N transformation rates. WP4 will determine the stability and persistence of the selected microbiota's effect across a panel of seven contrasting agricultural soils with varying N cycling properties. The project involves an interdisciplinary International Research Team that will contributes to three key HARMI Work Packages (WPs). It deciphers microbiota-host interactions (WP2) by investigating the eco-evolutionary feedbacks between host selection and microbiota selection. It looks for enhanced sustainability (WP3) since the direct goal is to manage microbial communities to improve N use efficiency, promoting sustainable agriculture and climate change mitigation (N2O reduction). The central methodology of artificial selection of entire microbial communities represents a novel concept in microbial biotechnology (WP4), generating tools for the development of effective future bio-inoculants. The project includes a collaboration between two laboratories of BFC region (Agroécologie & Biogeosciences) and two departments of the University of Illinois (Environmental Sciences & Crop Science), with planned exchanges.