Pseudomonas aeruginosa is a versatile opportunistic pathogen that thrives in hostile environments by tightly regulating zinc (Zn) homeostasis. The CzcRS two-component system is pivotal for Zn resistance, primarily by activating the CzcCBA efflux pump, yet its basal activity and full regulon remain poorly defined. Here, we analyzed putative CzcR targets under zinc sufficiency (ZS) and zinc excess (ZE) conditions in P. aeruginosa PAO1 using ChIP-seq. Under ZE, we identified 32 CzcR binding sites, potentially regulating 39 genes, many of which are linked to virulence, antibiotic resistance, and stress response. Under ZS, 10 binding sites were detected, revealing distinct CzcR targets. Considering the presence of a CzcR binding motif close to the peaks summit and RNA-seq data, we identified seven and four novel CzcR-regulated genes under ZE and ZS conditions, respectively, mostly implicated in bacterial virulence. Our findings highlight that CzcR may exhibit different functionalities depending on Zn concentration: its basal activity maintains physiological robustness, while its activated form orchestrates Zn detoxification and virulence modulation. This study expands our understanding of how P. aeruginosa integrates metal sensing with clinically relevant phenotypes, highlighting CzcR as a key regulator at the intersection of metal homeostasis and pathogenicity.

During the last decade, considerable efforts have been undertaken to achieve a “good ecological status” of European coastal waters and ensuring the development of methodological standards for the evaluation of this status. However, the current routine biomonitoring implicates time-consuming and costly manual sorting and morphological identification of benthic macrofauna. In our study, we tested the performance of environmental DNA metabarcoding targeting microbial communities and meiofauna as an alternative to traditional macrofauna-based monitoring. We focused on environmental impact assessment of offshore oil and gas industry. We used three genetic markers (18S V1V2, 18S V9 and COI) to assess the environmental pressures induced by the platforms. All markers showed patterns of alpha and beta diversity consistent with morphology-based macrofauna analyses, significantly changing along distance gradients from the platforms. The impact of the operational discharges was also detected by the variation of biotic indices values, AMBI index showing the best correlation between morphological and eDNA datasets. Finally, the sediment physicochemical parameters were used to build a local de novo pressure index that served as benchmark to test the potential of a taxonomy-free approach. Our study demonstrates that metabarcoding approach outperforms morphology-based approach and can be used as a cost and time-saving alternative solution to the traditional morphology-based monitoring in order to monitor more efficiently the impact of industrial activities on marine biodiversity.