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Dissecting host-microbe interactions with modern functional genomics.

Interrogation of host-microbe interactions has long been a source of both basic discoveries and benefits to human health. Here, we review the role that functional genomics approaches have played in such efforts, with an emphasis on recent examples that have harnessed technological advances to provide mechanistic insight at increased scale and resolution. Finally, we discuss how concurrent innovations in model systems and genetic tools have afforded opportunities to interrogate additional types of host-microbe relationships, such as those in the mammalian gut. Bringing these innovations together promises many exciting discoveries ahead.

Genomics

A fluorescent reporter system for tracking Lactobacillus casei T1 in the murine gastrointestinal tract.

BACKGROUND: Fluorescent reporter systems are useful for studying probiotic colonization and host-microbe interactions. However, their use in lactic acid bacteria is still limited by relatively weak fluorescence signals, insufficient expression stability, and limited resolution during in vivo imaging. In particular, efficient strain-specific tracking systems remain scarce. METHODS: Here, we developed a red fluorescent reporter system for Lactobacillus casei T1 (L.c T1). Lactate dehydrogenase (LDH) promoters identified from the L.c T1 genome were compared with the constitutive P32 promoter to drive expression of the red fluorescent proteins mCherry and mKate. The different promoter-reporter combinations were evaluated in both Escherichia coli DH5α and L.c T1. Fluorescence expression was further examined under different environmental pH conditions. The optimized reporter strains were then evaluated by whole-body fluorescence imaging in living mice and ex vivo imaging of gastrointestinal tissues following oral administration. RESULTS: Among the constructs tested, P32-mKate produced the strongest and most stable fluorescence signal in L.c T1. Fluorescence intensity was influenced by environmental pH, with higher signals observed under mildly alkaline conditions. Whole-body fluorescence imaging showed that the engineered strain could be detected in living mice following oral administration. Ex vivo imaging of gastrointestinal tissues provided clearer localization of fluorescence, with signals mainly detected in the stomach and upper small intestine. CONCLUSION: We established a stable and efficient red fluorescent reporter system for L.c T1. The P32-mKate system enables detection of the engineered strain both in vitro and in vivo and provides a practical approach for tracking probiotic distribution and studying host-microbe interactions in preclinical animal models.

Lactobacillus casei T1

Serine: From Metabolic Intermediate to Signaling Entity.

Serine, a nonessential amino acid classically defined as a precursor for protein synthesis and one-carbon metabolism, is increasingly recognized as a signaling metabolite that links the cellular metabolic status to regulatory decision-making. Intracellular serine availability is shaped by nutrient conditions, glycolytic flux, and activity of the serine synthesis pathway, and these fluctuations are sensed to elicit coordinated metabolic and signaling responses. This review discusses mechanisms by which serine modulates cell growth and stress responses, with particular emphasis on its interaction with central nutrient-sensing pathways, including mTORC1 and the integrated stress response. In parallel, serine-driven one-carbon metabolism is examined for its role in supporting nucleotide biosynthesis, methylation reactions, and redox homeostasis through folate-dependent pathways and NADPH generation, thereby coupling anabolic processes to the maintenance of redox balance and genome integrity. In addition to intracellular functions, serine contributes to intercellular signaling. Conversion of l-serine to d-serine mediates neuromodulatory activity via N-methyl-d-aspartate receptors, while serine availability also influences immune cell function, inflammatory signaling, and host-microbe interactions. Dysregulation of serine metabolism and signaling is further considered in the context of disease states, including cancer, neurodegeneration, and metabolic disorders. Together, these observations support a framework in which serine functions as an information-bearing metabolic signal that coordinates the biosynthetic capacity with cellular adaptation and intercellular communication.

Serine

Harnessing Probiotic LAB and Bacteriocins for Clean-Label Food Processing and Biopreservation: Omics, Molecular Innovations and Industrial Applications.

The persistence of microbial agents in foods, especially spore forming bacteria is one of the most significant challenges to food preservation and safety, undermining product quality, shelf life, and consumer health. The use of traditional control methods, including thermal processing and chemical preservatives, are increasingly limited by consumer demands for minimally processed foods, and the emergence of resistant microbial strains. Advances have been made in the use of probiotics like lactic acid bacteria (LAB) and their biometabolites like bacteriocins in food processing and preservation, particularly to control biofilm and endospore forming pathogens including Bacillus sp., Listeria sp., Staphylococcus sp., Clostridium sp., E. coli etc. in foods and food processing plants/surfaces. Given the ability of these organisms to cause foodborne illness and form resilient biofilms in the food processing ecosystem and their resistance to the conventional method of their elimination, the antimicrobial peptides (bacteriocins) are gaining increasing prominence as useful alternatives to synthetic antimicrobials in enhancing food safety and combating the threats of these pathogens. This review addresses current information on the inhibition of persistent microbial spoilage contaminants, biofilm-forming pathogens, and spore formers of interest to the food industry using LAB and their bacteriocins. Current developments in isolation, characterization, and mode of action of bacteriocins are explored, including synergistic activity with other preservative hurdle techniques such as encapsulation, and nanobiotechnology. Importantly, there is a focus on the utilization of molecular and omics-based approaches to enable a better understanding of bacteriocin biosynthesis, gene regulation, host-microbe interactions and gut microbiome regulation potential of probiotic LABs, permitting the rational development of targeted and strain-specific interventions. Developments in the incorporation of bacteriocin-producing LAB into functional starter cultures and bio-protective products, and challenges in stability, regulatory approval, and scalability for industrial use, are also discussed in the paper. Despite their considerable potential, broader translation remains constrained by regulatory requirements, production and formulation costs, variable efficacy in complex food matrices, and the limited validation of many candidate bacteriocins beyond laboratory and model-food systems. Collectively, these advances position LAB and their bacteriocins at the leading edge of developing sustainable, clean-label, and efficacious functional foods and food preservation systems. Their functionality can be expanded by integrating genomics, synthetic biology, and predictive modeling for the maximization of their biopreservative potential in diverse food matrices and in gut microbiota modulation.

Bioactive Peptides

Gut microbial genomes with paired isolates from China illustrate probiotic and cardiometabolic effects.

The gut microbiome displays genetic differences among populations, and characterization of the genomic landscape of the gut microbiome in China remains limited. Here, we present the Chinese Gut Microbial Reference (CGMR) set, comprising 101,060 high-quality metagenomic assembled genomes (MAGs) of 3,707 nonredundant species from 3,234 fecal samples across primarily rural Chinese locations, 1,376 live isolates mainly from lactic acid bacteria, and 987 novel species relative to worldwide databases. We observed region-specific coexisting MAGs and MAGs with probiotic and cardiometabolic functionalities. Preliminary mouse experiments suggest a probiotic effect of two Faecalibacillus intestinalis isolates in alleviating constipation, cardiometabolic influences of three Bacteroides fragilis_A isolates in obesity, and isolates from the genera Parabacteroides and Lactobacillus in host lipid metabolism. Our study expands the current microbial genomes with paired isolates and demonstrates potential host effects, contributing to the mechanistic understanding of host-microbe interactions.

Probiotics

16S rRNA and Metagenomic Datasets of Gastrointestinal Microbiota in Fetal and 7-Day-Old Goat Kids.

The perinatal period (from late gestation to the neonatal stage) in ruminants is a critical phase for fetal organ maturation, where ecological succession of gastrointestinal microbial communities significantly impacts livestock production efficiency. However, research remains insufficient regarding the distribution patterns and functional annotation of microbial communities across different gastrointestinal compartments during this period. This study characterized early microbiota dynamics in Hutianshi Goats using 16S rRNA sequencing (4 fetal goats at 90 ± 10 gestational days) and metagenomics (3 7-day-old goat kids). The fetal goat group generated 852,694 valid reads, yielding 688,277 high-quality reads after chimera removal for downstream analysis. The 7-day-old goat kids group produced 1,081,588,182 final valid reads, after data processing and assembly, 8,561,345 contigs were generated. Gene prediction identified 6,095,352 genes. Multi-database annotations (NR, KEGG, CAZy, etc.) revealed functional potential and antimicrobial resistance traits. The public release of this dataset facilitates academic understanding of microbial community dynamics and host-microbe interactions during this developmental stage, providing both theoretical foundations and data resources for ruminant developmental biology and precision breeding regulation.

Animals

Function-based selection of synthetic communities enables mechanistic microbiome studies.

Understanding the complex interactions between microbes and their environment requires robust model systems such as synthetic communities (SynComs). We developed a functionally directed approach to generate SynComs by selecting strains that encode key functions identified in metagenomes. This approach enables the rapid construction of SynComs tailored to any ecosystem. To optimize community design, we implemented genome-scale metabolic models, providing in silico evidence for cooperative strain coexistence prior to experimental validation. Using this strategy, we designed multiple host-specific SynComs, including those for the rumen, mouse, and human microbiomes. By weighting functions differentially enriched in diseased versus healthy individuals, we constructed SynComs that capture complex host-microbe interactions. We designed an inflammatory bowel disease SynCom of 10 members that successfully induced colitis in gnotobiotic IL10-/- mice, demonstrating the potential of this method to model disease-associated microbiomes. Our study establishes a framework for designing functionally representative SynComs of any microbial ecosystem, facilitating mechanistic study.

Animals

Endozoicomonas acroporae enhances coral thermal resilience through host-microbe coordination.

Probiotics hold promise for enhancing coral resilience under climate-driven thermal stress, yet their mechanisms remain poorly understood. Although the bacterial genus Endozoicomonas has been proposed to benefit corals, in vivo evidence of beneficial effects on the host remains limited. Here, we establish Endozoicomonas acroporae Acr-14T as a coral probiotic and characterize its effects on the reef-building coral Stylophora pistillata. We show that E. acroporae Acr-14T enhances host thermal tolerance, colonizes coral tissues, and forms coral-associated microbial aggregates. Microbial profiling indicates that probiotic treatment is associated with reduced relative abundances of opportunistic microbes and enrichment of putatively beneficial taxa. To support transcriptomic analyses, we assembled a chromosome-level genome of S. pistillata clade 1 (Pacific lineage) and found that E. acroporae Acr-14T treatment mitigates heat-induced protein-folding stress and apoptotic signaling. Single-cell transcriptomics further revealed altered expression of genes involved in S-adenosylmethionine (SAMe) metabolism and pro-survival signaling in gastrodermal cells of probiotic-treated corals. Together, our results provide a cell-type-resolved view of host responses linked to Endozoicomonas-mediated coral thermal resilience and offer insight into molecular mechanisms implicated in host-microbe interactions under environmental stress.

Animals

Systematic identification and characterization of regulators of aryl hydrocarbon receptor signaling.

The human aryl hydrocarbon receptor (AHR) integrates chemical signals derived from the environment, gut microbes, and endogenous sources to regulate processes ranging from intestinal barrier integrity to xenobiotic detoxification. Despite strong evidence that dysregulation of AHR signaling is a causal factor in metabolic and autoimmune disorders, we currently lack a comprehensive understanding of the factors that regulate AHR activity in human cells. Here, we use genome-scale CRISPR screening to systematically identify regulators of AHR signaling in hepatocytes. The resulting datasets recapitulate the core AHR signaling pathway and identify a large network of regulators. Many of these factors have roles beyond AHR signaling, reflecting that AHR signaling is deeply integrated into human cell biology. We further dissect this network to reveal novel modes of regulation of AHR expression, protein levels, and signaling. For example, we find that the E3 ubiquitin ligase UBR5 sustains AHR signaling by counteracting degradation of ligand-bound AHR. Finally, we identify components of the AHR regulatory network that are specific to cell types and ligands as potential nodes to manipulate AHR signaling in a targeted manner for therapeutic benefit. Overall, our results define the regulatory network that underpins AHR activation, with implications for our understanding of host-microbe interactions and integrative chemosensation and the etiology of metabolic and inflammatory disorders.

Journal Article

Population heterogeneity in Helicobacter pylori PMSS1 shapes variable mouse infectivity: derivation of the homogeneous reference strain PMSS2.

UNLABELLED: Experimental infection models are widely used to investigate host-microbe interactions, often under the assumption that bacterial populations are genetically uniform. Here, we examined population heterogeneity in the widely used Helicobacter pylori strain PMSS1 and its relationship to variation in mouse infectivity. Single-colony isolates derived from PMSS1 displayed substantial differences in colonization efficiency, indicating that pre-existing variation within the population contributes to infection outcomes. To distinguish the effects of initial population heterogeneity from changes arising during infection, we analyzed PMSS2, a genetically homogeneous reference strain derived from PMSS1 that exhibited consistent infection phenotypes across independently isolated clones. Comparative genomic analysis of isolates recovered from infected mice revealed differences in the extent and patterns of genomic variation between PMSS1- and PMSS2-derived populations. These results demonstrate that variability in infection outcomes can arise from pre-existing heterogeneity within bacterial populations and highlight the importance of considering population composition when interpreting experimental infection studies. IMPORTANCE: Animal infection models are widely used to study how bacterial pathogens cause disease and change during infection. These studies often assume that the bacteria used for infection are genetically uniform. Our study shows that this assumption may not always hold. We found that a commonly used Helicobacter pylori strain contains hidden genetic diversity that leads to large differences in how well bacteria infect mice. By comparing this strain with a genetically uniform derivative, we show how differences present before infection can shape infection outcomes and influence the genetic changes observed during infection. Our findings highlight the importance of considering starting population diversity when interpreting experimental infection studies and are broadly relevant to research on microbial pathogenesis.

Helicobacter pylori

Bridging the airway microbiome and targeted therapy in bronchiectasis: multi-omics insights, endotypes and emerging therapies.

Bronchiectasis is a heterogeneous chronic airway disease primarily driven by persistent infection, microbial dysbiosis and dysregulated host immunity. While culture-based microbiology has historically informed clinical management, advances in high-throughput sequencing and multi-omic technologies have transformed our understanding of the airway ecosystem, revealing that disease activity is shaped not only by individual pathogens, but by complex and dynamic host-microbe interactions. Despite the breadth of descriptive microbiome data, translation into clinically actionable diagnostics or therapies has been limited. Importantly, cross-sectional correlations between microbiota and inflammation do not establish cause and effect, underscoring the need to embed host-microbiome profiling within both longitudinal and interventional therapeutic trials. In this review, we critically appraise current microbial and host multi-omics research in bronchiectasis, integrating microbiome studies with host inflammatory, proteomic and immunophenotyping data. We highlight themes emerging across cohorts, including low microbial diversity, pathogen dominance, loss of commensal networks and neutrophil-driven inflammation, and discuss how these features align with biological endotypes associated with exacerbations and treatment response. Drawing on lessons from host-directed therapeutic successes, we examine translational roadblocks limiting microbiome-guided care. We further review emerging microbiome-modulating strategies such as pathogen-specific biologics, bacteriophage therapy, live biotherapeutic products, biofilm-targeting adjuncts and precision antibiotic stewardship. Finally, we propose a roadmap toward microbiome-informed precision medicine through harmonised methodologies, integration of host and microbial biomarkers into clinical trials, and embedding multi-omics pipelines within large international registries. Collectively, these advances have the potential to shift bronchiectasis research and clinical management towards rationally designed, precision medicine-driven therapeutic strategies.

Humans

Insect immune systems: same same but different but still same.

Insects are the most diverse group of animals in nature, occupying nearly every ecological niche and playing central roles as pollinators, pests, and disease vectors. Despite this vast diversity, insects rely on a set of conserved yet evolutionarily adaptable immune pathways to defend against pathogens. Early studies in insect immunity have laid the foundation for human immunology, and recent advances in genomic and transgenic technologies have renewed interest in understanding how immune responses vary across insect orders. Insects are highly diverse in their immune systems; each species has unique immune responses that help fight infections from specific pathogens. Nevertheless, they share multiple aspects of recognition, regulation, and effector mechanisms. This review focuses on current knowledge of the immune systems of major insect lineages to highlight both shared signaling pathways, immune cells, and humoral factors, as well as lineage-specific responses that reflect distinct ecological pressures that have shaped the host-microbe interactions. Comparing different insect species and orders not only provides insights into the evolutionary divergences and convergences of immune system features but also offers complementary knowledge among species within the same order, helping fill existing gaps. Understanding these evolutionary patterns not only deepens our understanding of insect immunity but also informs the development of transgenic strategies to disrupt pathogen transmission in key vector species.

Animals

Autoimmune disease-associated pathobionts: mechanisms and therapeutic potential of phage-based approaches.

The gut microbiota is a critical regulator of systemic immune homeostasis; accumulating evidence implicates specific commensal bacteria, termed "pathobionts," in autoimmune disease pathogenesis. However, the definition of pathobionts remains context-dependent, as their effects are influenced by host genetics and host-microbe interactions. In this review, we summarize representative pathobionts supported by functional evidence in selected extraintestinal autoimmune diseases and discuss how these mechanisms may inform phage-based microbiome-targeted interventions. Mechanistically, pathobionts contribute to autoimmune disease through multiple pathways, including molecular mimicry, induction of intestinal T helper 17 and T follicular helper cell responses, disruption of regulatory T cell homeostasis, intestinal barrier dysfunction, and bacterial translocation from the gut to extraintestinal sites. These processes highlight the central role of gut-associated lymphoid tissue in initiating systemic autoimmunity, and targeting disease-associated microbes represents a promising therapeutic strategy. Whole-phage therapy, which enables highly specific bacterial elimination, has shown efficacy in preclinical immune-mediated disease models, but may be affected by variable in vivo replication, bacterial receptor-mediated resistance, anti-phage immune responses, and ecological effects on the resident microbiome. Phage-derived enzymes that lyse bacterial cell walls, such as endolysins, represent a complementary therapeutic modality that specifically targets bacterial peptidoglycan through cell wall-binding and catalytic domains. Collectively, these findings support the concept that pathobiont-targeted interventions, particularly phage-based strategies, may provide microbiome-directed, immunosuppression-sparing therapeutic approaches for selected patient subsets.

Humans

First Report and Integrated Characterization of Aeromonas veronii Associated with the Protected Fish Diptychus maculatus in Xinjiang, China.

Aeromonas veronii is a widely distributed opportunistic aquatic pathogen associated with diseases in freshwater fish. Despite the ecological and conservation significance of Diptychus maculatus, a protected cold-water fish inhabiting high-altitude ecosystems, information regarding its associated bacterial communities remains limited. This study aimed to isolate and characterize A. veronii recovered from D. maculatus and provide baseline information on its occurrence and phenotypic characteristics. Eight bacterial isolates were recovered from various tissues, including skin, gills, eye, intestine, dorsal fin, body kidney, gonad, and spleen of randomly sampled fish individuals from Xinjiang, China. Phenotypic and biochemical characterization, together with 16S rRNA sequencing, supported their identification as A. veronii, while gyrB analysis of a representative isolate provided additional species-level confirmation. Antimicrobial susceptibility testing revealed a consistent multidrug-resistance phenotype among all isolates. The isolates were susceptible to enrofloxacin, cefotaxime, ceftriaxone, and florfenicol. Intermediate responses were observed for ciprofloxacin, ofloxacin, doxycycline, oxytetracycline, and trimethoprim-sulfamethoxazole, whereas resistance was detected against norfloxacin, neomycin, penicillin, amoxicillin, tetracycline, and erythromycin. In vitro biofilm assays demonstrated weak to moderate biofilm-forming capacity among isolates. These findings provide baseline data for wildlife microbial surveillance and conservation-oriented monitoring of protected fish populations, supporting future investigations into environmental monitoring, genomic characterization, and host-microbe interactions.

Aeromonas veronii

Complete genome sequence and genomic characterization of the probiotic Limosilactobacillus reuteri PSC102.

BACKGROUND: Gut microbiota are potential sources of probiotics and play an essential role in maintaining intestinal health. Limosilactobacillus reuteri PSC102 (L. reuteri PSC102), which was isolated from the feces of healthy pigs, exhibited health-beneficial properties. AIM: We aimed to conduct a whole-genome sequencing analysis of L. reuteri PSC102 to determine its molecular characteristics as a probiotic strain. METHODS: Limosilactobacillus reuteri PSC102 cells were cultured in De Man-Rogosa-Sharpe medium, followed by DNA extraction for genomic analysis using the PacBio-Illumina sequencing platform. The EzBioCloud software was used to perform gene assembly, and the genes were interpreted by the National Center for Biotechnology Information (NCBI) and the Glimmer program. Core and pan-genomic analyses were performed to assess the extent of functional conservation in the genomic sequence. Moreover, the NCBI database and the Basic Local Alignment Search Tool software were used to identify antimicrobial resistance genes and virulence factors. RESULTS: Limosilactobacillus reuteri PSC102 consists of a single circular chromosome with 2,048,626 bp, a guanine- cytosine of 38.9%, 18 rRNA genes, and 69 tRNA genes. Among the 1,846 protein-coding sequences, genes associated with probiotic characteristics were identified, including genes involved in host-microbe interactions, stress tolerance, biogenesis, and defense mechanisms. Furthermore, the genome of L. reuteri PSC102 comprises 2,446 pan-genome and 1,222 core-genome orthologous gene clusters. A total of 74 unique genes were identified in L. reuteri PSC102 genome. These genes mostly encode proteins potentially involved in the transport and metabolism of amino acids and carbohydrates. Moreover, antibacterial resistance genes and virulence factors were absent in L. reuteri PSC102. CONCLUSION: The results of the molecular insight into L. reuteri PSC102 corroborates its use as a probiotic in humans and other animals.

Limosilactobacillus reuteri

Substrate recognition and cleavage by mucin degrading O-glycopeptidases from the gut microbe Bacteroides caccae.

O-glycopeptidases are enzymes that hydrolyze the peptide bonds in glycoproteins by a mechanism that involves specific recognition of O-linked glycans on the substrate. Bacteroides caccae, an accomplished mucin degrader, is a member of the human gut microbiota with sixteen genes encoding putative O-glycopeptidases in the peptidase_M60 family. At present, the diversity of substrate selectivity in O-glycopeptidases is not well-understood, nor is the rationale behind their expansion in bacteria such as B. caccae. Here, we reveal the activity and diversity of the peptidase_M60 O-glycopeptidases encoded in the B. caccae genome. At least thirteen of the sixteen peptidase_M60 encoding genes produce active mucinolytic enzymes. Targeted functional studies by a high-throughput FRET screen combined with detailed kinetic analyses reveal that five examples in an uncharacterized clade of peptidase_M60 proteins are specifically O-glycopeptidases with different substrate selectivities despite their relatively high degree of relatedness. Structural analyses of these enzymes, including bound complexes, reveal new insight into the molecular underpinnings of O-glycopeptidase diversity. This highlights the larger context of how varied the selectivity of peptidase_M60 O-glycopeptidases can be for the glycan moiety and/or the peptide portion of the substrates, and why mucin degraders like B. caccae diversify O-glycopeptidase substrate repertoires to potentially maximize breakdown of this extraordinarily complex polymer.

Mucins

Symbiotic interactions and climate change implications of the octocoral microbiome.

Octocorals are vital components of tropical, temperate, and cold-water benthic marine ecosystems. Their associated microbiomes, comprising microeukaryotes, prokaryotes, and viruses, are increasingly recognised as central to host health, nutrient cycling, and chemical defence. Metagenomics and amplicon sequencing have uncovered taxonomic and functional complexity within these microbial communities, revealing patterns of host specificity and health status, along with seasonality and geographic structuring. However, anthropogenic stressors, particularly those associated with global climate change, exert intense pressure on coral-dominated ecosystems, leading to complex and poorly understood local and regional patterns of octocoral expansion and mortality. Microbial interactions may be a main driver of these contrasting outcomes by mediating the ecological resilience of octocorals to environmental stress. We synthesise the current state of research on the diversity, organisation, and function of the octocoral microbiome, and identify critical knowledge gaps on octocoral holobionts relative to scleractinian corals. Our meta-analysis of 79 publicly available bacterial genomes from octocorals reveals group-specific specialisation in denitrification and nitrate assimilation, along with widespread capacities for essential amino acid, cofactor, and vitamin production, suggesting important contributions to nutrient cycling in the holobiont. While sampling efforts between cultured and uncultured lineages are even, our genomic survey reveals strong sampling bias toward the Atlantic Ocean, temperate gorgonians, and healthy host states, whereas bacterial genomes representing the pathobiome, tropical and/or deep-sea regions, and other octocoral taxa remain underrepresented. Accordingly, we propose future research directions to advance understanding of octocoral microbiome ecology and its role in the resilience of tropical, temperate and cold-water coral reefs.

Endozoicomonadaceae

Advancing the Deciphering of Host-Microbe Crosstalk with Spatial Omics: A Mini-Review.

Host-microbe crosstalk refers to the reciprocal influences between a host and its resident or invading microorganisms. This crosstalk plays important roles in maintaining host health, regulating physiological functions, and coordinating responses to infection. The rapid rise of spatial omics is transforming how this crosstalk is studied in both animals and plants. Unlike traditional bulk omics, which homogenize tissues and erase spatial context, spatial methods preserve in situ organization and can simultaneously capture molecular information from hosts and microbes. As a result, researchers can characterize the spatial organization of colonization and infection, identify spatial associations between microbial niches and host cell states, and visualize local host response gradients across intact tissues. Current spatial omics technologies encompass sequencing-based, imaging-based, and hybrid platforms. Spatial multi-omics approaches enable the joint measurement or integration of gene expression, protein abundance, and metabolite distributions. Although spatial association alone does not establish causality, spatial omics provides a high-resolution framework for characterizing host-microbe relationships within intact tissues and generating spatially constrained, testable hypotheses. When combined with perturbation experiments and complementary experimental evidence, these hypotheses can contribute to mechanistic interpretation of host-microbe crosstalk. Here, we review spatial omics technologies, compare their suitability and major trade-offs for host-microbe studies, and discuss computational strategies, analytical challenges, and future prospects.

Multiomics