Metals are essential trace elements for almost all organisms including bacteria. Yet, metals are toxic at high concentrations, requiring fine-tuned regulatory mechanisms to steer metal homeostasis inside cells. In this primer, we explain how bacterial metallophores – small secreted secondary metabolites – act as gatekeepers by carefully orchestrating the scavenging and uptake of essential metals whilst preventing intracellular toxicity and keeping toxic metals outside the cell. We further introduce metallophore diversity together with main synthesis, secretion and uptake mechanisms. Finally, we show how secreted metallophores shape ecological interactions between bacteria and with eukaryotic organisms and how fundamental research on metallophores opens promising avenues for therapeutic and biotechnological applications.

Coral diseases are increasing in prevalence, accelerating the global decline of tropical reefs, which threatens over 25% of marine biodiversity and vital ecosystem services for human societies. While outbreaks are frequently linked to environmental change, including heat stress, sedimentation, and reduced water quality, the mechanisms by which such factors promote disease remain poorly understood. Here we show that nutrient stress, caused by skewed seawater nitrogen-to-phosphorus (N:P) stoichiometry, promotes the onset of Black Band Disease (BBD), a common and easily recognisable syndrome that affects corals around the globe. Using Turbinaria reniformis as a model system, controlled laboratory experiments demonstrate that skewed N:P ratios disrupt the functional integrity of coral-associated microbial networks while favouring opportunists that exploit dysfunctional host–symbiont interactions. Disease lesion-associated microbial mats are dominated by cyanobacteria and include sulphur-metabolising bacteria, hallmarks of natural BBD communities. Strikingly, similar cyanobacterial taxa are also detected in the visually healthy coral tissue ahead of the expanding lesions, suggesting an opportunistic recruitment of disease-associated members from the resident microbiome. Global analyses of BBD outbreaks reveal that over 88% occurred in regions with skewed N:P ratios, compared with only 16% that were linked to prior heat stress. Together, our findings identify nutrient-driven microbiome destabilisation as a key pathway to coral disease, reinforcing nutrient management as a major lever for reef conservation and restoration practice. Coral diseases contribute to the decline of reefs around the globe. This study reveals that disruptions of the nutrient balance in seawater can change coral-associated microbial communities leading to disease.

The biological significance of the transition metal molybdenum (Mo) lies in its function at the catalytic center of several enzymes that drive a wide spectrum of redox reactions underlying global biogeochemical cycles, yet a paradox persists. While modern life ubiquitously relies on Mo, geochemical evidence suggests that its availability in early Earth’s anoxic oceans was extremely limited. Modern organisms can use Mo down to trace levels; however, the rates of Mo-dependent metabolisms slow down when Mo availability decreases, posing fundamental questions about the extent to which changing Mo abundances shaped the evolution of molybdoenzymes, and when early life began harnessing Mo. Here, we confront this evolutionary enigma by reconstructing the temporal and ecological emergence of molybdoenzymes, their transport systems, and biosynthetic pathways. In parallel, we examine biological tungsten (W) usage due to shared chemical properties and cofactor biosynthetic pathways with Mo. We provide molecular dating evidence of Mo/W utilization back to the Eo- to Mesoarchean (~3.7–3.1 Ga). These findings challenge prevailing assumptions about trace metal availability on the early Earth and underscore the profound antiquity and adaptability of Mo-based biochemistry in shaping early microbial evolution. The study shows that life began using molybdenum and tungsten enzymes as early as 3.7–3.1 billion years ago. Study reveals that key metabolic processes arose despite scarce metals and highlighting the early adaptability of microbial life.

Despite considerable powers, the application of CRISPR activation (CRISPRa) screens in primary human cells remains a formidable challenge. Here, we develop dCas12f1-SAM, a compact SAM-based transcriptional activation platform, that outperforms existing systems in both immortalized cell lines and primary human T cells and hematopoietic stem/progenitor cells (HSPCs). Using dCas12f1-SAM, we perform a pooled CRISPRa screen targeting 1559 human transcription factors (TFs) in primary human T cells and identify multiple positive regulators of IL-2 expression. We further implement a single-cell CRISPRa screen via our miCROP-seq construct, resolving how these genetic perturbations reshape T cell activation dynamics and drive functionally distinct cellular states. Among the top-ranking genes, we spotlight KLF12 and LHX5, whose overexpression significantly improves antigen-specific responses of chimeric antigen receptor T (CAR-T) cells. Collectively, these findings establish dCas12f1-SAM as a robust transcriptional activation tool, highlighting its potential to advance applications in cellular engineering and immunotherapy. CRISPRa screening in primary human cells has remained a formidable technical challenge. Here, the authors developed dCas12f1-SAM and successfully implemented a gain-of-function screen in primary human T cells, identifying key regulators of T cell activation.

xBind is an interactive, freely accessible, and fully configurable webserver for large language model (LLM)-enabled cross-molecular protein binding-site prediction. xBind leverages LLM embeddings from the ESM-2 model together with sequence- and structure-derived features to predict protein–protein, protein–DNA, and protein–RNA binding sites using symmetry-aware deep graph neural networks. The input to xBind is either a single-chain protein sequence in FASTA format or a monomer protein structure in PDB or mmCIF format and it outputs predicted residue-level binding sites of the input protein with its pre-selected interaction partner. The customizable xBind web interface provides: (i) choice of interaction partners including protein–protein, protein–DNA, and protein–RNA; (ii) on-the-fly AlphaFold-based protein structure prediction for sequence-only inputs; (iii) on-demand selection of the likelihood threshold for calibrating structure-aware binding site annotations; (iv) interactive and interpretable web-based results, including sequence and structural visualizations and plots of residue-level binding likelihoods with user-adjustable threshold calibration; and (v) extensive help information for usage and results interpretation through a web-based tutorial and guide. xBind is freely available at https://fusion.cs.vt.edu/xBind.

Elucidating gene function in highly redundant genetic programs such as signaling pathways is challenging in model and nonmodel plants with current whole-plant genetic screening tools. Many of these challenges could be overcome if screens were instead carried out using individual cells harboring genetic perturbations. Here we report a single-cell screening platform, PIVOT (protoplast isolation after virus overexpression in planta), to accelerate identification and functional characterization of plant genes. We use Nicotiana benthamiana as a heterologous host to test gene libraries arrayed in a single leaf. PIVOT harnesses viral superinfection exclusion to ensure single multiplicity of infection per cell during pooled library delivery. Additionally, we engineer a cell-surface protein as a phenotypic marker for isolating cells of interest from a heterogeneous population. Using this system, we recover regulators of cytokinin signaling from an Arabidopsis open reading frame library. We anticipate PIVOT will be broadly applicable for high-throughput, single-cell functional genetic screening across the plant kingdom. A pooled, cell-based, genetic screening platform in plants is used for the functional analysis of cytokinin signaling proteins.