Phyto-rhizoremediation is a promising sustainable technology for pollutant clean-up provided by the plant holobiont, composed by the host plant and its microbiota. Plant root exudation is modulated by the pollution stress and has a key role in the activation of the microbial degrading metabolism. Despite the well documented role of the plant holobiont in ecosystem services, the complex interactions between host and microbiome are poorly understood, in particular in contaminated environments. The project will span metabolomics, biosensors and an innovative application of microsensor/sensor devices to profile the chemistry of the root microenvironments and the plant-triggered activation of degrading bacteria. The study will be applied to the site of Brescia-Caffaro, one of the largest sites in Europe contaminated by polychlorinated biphenyls (PCBs). The project aims to sort out the temporal and spatial synergistic interplay within the plant holobiont components and the geochemistry of rhizosphere micro-niches supporting microbial degradation. The project outcomes will provide a comprehensive understanding of the plant holobiont applied to environmental biotechnology, focusing on the soil microbiome degradative potential.