Domestication and intensive management practices have significantly shaped characteristics of modern crops. However, our understanding of domestication’s impact had mainly focused on aboveground plant traits, neglecting root and rhizospheric traits, as well as trait-trait interactions and root-microbial interactions. To address this knowledge gap, we grew modern ( Hordeum vulgare L. var. Barke) and wild barley ( H. spontaneum K. Koch var. spontaneum) in large rhizoboxes. We manipulated soil microbiome by comparing disturbed (sterilized soil inoculum, DSM) versus non-disturbed (non-sterilized inoculum, NSM) microbiome Results showed that modern barley grew faster and increased organic-carbon exudation (OC EXU) compared to wild barley. Interestingly, both barley species exhibited accelerated root growth and enhanced OC EXU under DSM, indicating their ability to partially compensate and exploit the soil resources independently of microbes if need be. Plant trait network analysis revealed that modern barley had a denser, larger, and less modular network than wild barley indicating domestication’s impact on trait coordination. Further, soil microbiome influenced specific network parameters. While the relative abundance of bacteria didn’t vary between wild and modern barley rhizospheres, species-specific core bacteria were identified, with stronger effects under DSM. Overall, our findings highlight domestication-driven shifts in root traits, trait coordination, and their modulation by the soil microbiome.

Understanding whether land use intensification causes regime shifts is of key importance for management, particularly if these shifts are associated with thresholds separating different ecosystem states and with hysteretic dynamics. Here we use a unique, long-term grassland database to identify thresholds in the response of 16 ecosystem functions and the diversities of 21 taxa to land use intensity. We show that aboveground diversity (5 of 10 taxa), shoot biomass and soil N retention showed threshold responses to land use intensity, i.e., abrupt changes between extensively and intensively managed grasslands. Time-series analysis revealed that ecosystem functions showed hysteresis around the threshold, while diversity did not. Shifting back to the functioning seen in extensively managed grasslands may therefore require larger reductions in land use intensity than shifting to the high intensity state. Identifying such thresholds along land use gradients is critical to prevent ecosystem degradation and conserve biodiversity and ecosystem functions.

Plants harbor a wide range of leaf-feeding insects. Insect survival and fitness are influenced by both energy-rich molecules and phytochemicals in the host foliage. Yet, how leaf chemical diversity and insect microbiota - key factors in ecological and physiological processes – shape insect nutrition and impact insect performance is still poorly understood. Here we forced Tortrix viridana larvae, an oak-specialized herbivore, to feed on two Quercus robur susceptible and resistant metabolic phenotypes (metabotypes) and examined leaf, salivary, and fecal metabolomes associated with larval performance, mortality, and fecal microbiota. We show that host chemical diversity affects larval development and that the distinct signatures of oak metabotypes are maintained in the insect digestive system. Larvae were highly efficient in nutrient assimilation and able to minimize plant chemical defenses, thanks in part to the adaptation of the gut microbiota to the different food qualities.

Soil organic matter is composed of fractions with different functions and reactivity. Among these, particulate organic matter (POM) is the main educt of new inputs of organic matter in soils and its chemical fate corresponds to the first stages of the SOM decomposition cascade ultimately leading to the association of organic and mineral phases. We aimed at investigating the POM molecular changes during decomposition at a sub-millimetre scale by combining direct measurements of POM elemental and molecular composition with laboratory imaging VNIR spectroscopy. For this, we set up an incubation experiment to compare the molecular composition of straw and composted green manure, materials greatly differing in their C/N ratio, during their decomposition in reconstituted topsoil or subsoil of a Luvisol, and recorded hyperspectral images at high spatial and spectral resolutions of complete soil cores at the start and end of the incubation. Hyperspectral imaging was successfully combined with machine learning ensembles to produce a precise mapping of POM alkyl/O-N alkyl ratio and C/N, revealing the spatial heterogeneity in the composition of both straw and green manure. We found that both types of organic amendment were more degraded in the reconstituted topsoil than in subsoil after the incubation. We also measured consistent trends in molecular changes undergone by straw, with the alkyl/O-N alkyl ratio slightly increasing from 0.06 to 0.07, and C/N dropping by about 40 units. The green manure material was very heterogeneous, with no clear molecular changes detected as a result of incubation. The visualisation approach presented here enables high-resolution mapping of the spatial distribution of the molecular characteristics of organic particles in soil cores, and offers opportunities to disentangle the roles of POM chemistry and morphology during the first steps of the decomposition cascade of organic matter in soils.