Biology subjects

Zhang, H.

Publications and source records attributed to Zhang, H..

At least 127 records · Page 7Linked to original sources

bioRxiv2026

EpiReasoner: An Integrated Artificial Intelligence Framework for Phenotype-to-Genotype Reasoning in Plant Epidermal Development

Achieving high-throughput and precise phenotypic quantification and imaging modalities of stomatal and epidermal cells across diverse species remains a primary bottleneck in elucidating the mechanisms of stomatal dynamics, epidermal patterning, and environmental adaptation of plants. Here, we developed EpiReasoner, an artificial intelligence framework comprising a vision module, EpiVision, and a knowledge-based reasoning module, EpiBrain, for the quantitative phenotypic analysis and domain-specific knowledge reasoning of stomatal complexes and pavement cells in plants. Operating across bright-field, scanning electron microscopy, and differential interference contrast modalities, EpiVision achieves precise instance segmentation in various monocotyledonous, dicotyledonous, and fern species. Its performance significantly surpasses current state-of-the-art models. Moreover, we defined 23 quantitative indices describing stomatal cell morphology and spatial distribution. For domain-specific tasks such as phenotype prediction, genotype deduction, and molecular mechanism reasoning, EpiBrain demonstrates a human preference rate significantly higher than that of general-purpose large language models, including GPT-5 and Claude Sonnet 4. The application of EpiReasoner to phenotypic data of stomatal density derived from a tomato natural population of 170 accessions successfully identified a major quantitative trait locus on chromosome 8. The candidate gene, SKP1-interaction partner 19L (SKIP19L), encoding an F-box family protein, exhibited severe allele frequency drift during tomato domestication, which is highly consistent with the adaptive trend of reduced stomatal density under artificial selection. EpiReasoner provides a novel paradigm that unifies visual phenomics and knowledge-driven reasoning for the biology of stomata and pavement cells, thereby significantly accelerating scientific discovery in plant science.

plant biology↗

bioRxiv2026

cfMIND: A read-level methylation framework for accurate non- invasive disease detection using cell-free DNA

Plasma cell-free DNA (cfDNA) emerged as a promising non-invasive biomarker for cancers. However, reliable detection remains challenging due to the low abundance of tumor-derived cfDNA fragments and the dilution of informative methylation signals when aggregated into region-level features. Here, we propose a novel approach cfMIND, an efficient and robust machine-learning framework that leverages stratified read-level methylation signals to preserve rare cell-type-specific information and enhance detection sensitivity. By avoiding information loss inherent to conventional aggregation strategies, cfMIND enables more accurate and stable inference across diverse conditions. cfMIND is compatible with various cfDNA methylation sequencing technologies and cancer types. Across multiple cancer datasets (n = 868), cfMIND achieves high performance (AUROC up to 0.966) and maintains strong accuracy even at ultra-low sequencing depth (0.2x) and in early-stage cancers. Notably, cfMIND demonstrates exceptional robustness, generalizing effectively across cohorts and platforms without the need for model retraining. These results highlight its potential utility in heterogeneous experimental and clinically relevant settings. Beyond cancer detection, cfMIND is readily extendable to non-malignant diseases, as demonstrated by its ability to capture disease-associated methylation alterations in amyotrophic lateral sclerosis (ALS). Functional investigations on cfMIND-identified features further reveal enrichment in key regulatory regions implicated in disease pathogenesis and recapitulate tissue- and single-cell-level methylation and transcriptional programs underlying tumor biology. Collectively, cfMIND represents a significant advancement in the field, offering a broadly applicable, functionally interpretable, and high-resolution framework for non-invasive disease detection.

bioinformatics↗

bioRxiv2026

The Vagus Nerve conducts viable translocation of gut flora to the lungs that impacts interstitial lung disease severity in mice

Communication between gut microbiota and extraintestinal organs is increasingly recognized, yet elucidation of relevant translocation mechanism(s) remains enigmatic. Vagus neuroanatomy and reports of vagal protein transfer to extraintestinal organs suggest that this "superhighway" could translocate bacteria. Here we explore whether the vagus superhighway can translocate bacteria to extraintestinal organs. Gavage of green fluorescent protein-expressing Escherichia coli (GFP-E. coli) into germ-free (GF) or specific-pathogen free (SPF) C57BL/6 mice yielded high bacillary loads in the stomach and lungs, followed by the heart, stool and peripheral muscles, despite negative blood cultures. Notably, confocal microscopy and culture revealed GFP-E. coli within the vagus nerve within five minutes of gavage suggesting rapid translocation. Metagenomic analysis of stool, lung, heart, vagus nerve, and muscle from non-gavaged SPF mice demonstrated significant microbial overlap, supporting that bacterial translocation occurs despite the presence of endogenous microflora. Remarkably, subdiaphragmatic vagotomy performed prior to GFP-E. coli gavage resulted in marked reductions of bacterial transduction in the lungs and other extraintestinal organs, except muscle. Furthermore, vagotomy significantly reduced lung fibrosis in SPF mice following intranasal bleomycin administration. In lung cancer patients undergoing lobectomy, vagotomy inhibited postsurgical reductions in forced vital capacity. These findings identify the vagus nerve as a literal gut-lung axis, facilitating viable bacterial translocation and influencing lung severity.

microbiology↗

bioRxiv2026

Large-Scale Assessment of NF1 Single Amino Acid Variants as HLA Class I Neoantigens

Neoantigens are cancer-specific antigens arising from genomic alterations. Single Amino Acid Variants (SAAVs) represent a primary class of these neoantigens. To evaluate the therapeutic potential of Neurofibromin 1 (NF1)-derived SAAVs - given that NF1 is frequently mutated in malignant brain tumors - we prioritized the 40 NF1 SAAVs determined to be HLA-A*02:01 binders using computational prediction coupled with experimental validation. To validate these predicted neoepitopes, we employed a two-tiered experimental approach in HLA-A*02:01 homozygous U87-MG cells. We first synthesized minigene constructs encoding the predicted neoepitopes, introduced them via lentiviral transfection and confirmed their expression by mass spectrometry (MS). Subsequently, we performed endogenous validation using pan-HLA immunoprecipitation mass spectrometry (IP-MS), confirming 4 (10 neoepitopes) of the 40 candidate SAAVs. We observed a discrepancy between in silico predictions and the observed sequences. Our endogenous peptidomics further revealed conserved peptide motifs and demonstrated that peptide selection for HLA presentation is transient. While our study substantiates the therapeutic feasibility of T-cell immunotherapies targeting NF1 mutations, these results underscore a limitation in current computational prediction. Our study highlights the necessity of experimental validation to refine neoantigen prioritization strategies.

immunology↗

bioRxiv2026

Bacterial Membrane Vesicles in Wastewater Disseminate Antibiotic Resistance Genes

Bacterial membrane vesicles (BMVs) have emerged as important contributors to the dissemination of antibiotic resistance genes (ARGs) in the environment. Here, we developed a high-performance immunomagnetic isolation method that improves the purity and selectivity of BMV recovery from wastewater, minimizes contamination from eDNA and viruses, and enables differentiation of BMVs originating from Gram-positive versus Gram-negative bacteria with minimal cross-reactivity. Using this approach, we found that ARGs such as the kanamycin resistance gene (kanR) was highly abundant in BMVs from both raw and treated wastewater, exhibited persistence following treatment, and retained the ability to generate antibiotic-resistant bacteria via transformation. Metagenomic sequencing further revealed that tetracycline resistance genes were the most abundant ARG class across all wastewater samples, while the composition of BMV-associated ARGs differed from the bulk ARG profile. These findings highlight the critical yet underrecognized role of BMVs in the spread of antimicrobial resistance and underscore the need to address BMV-mediated pathways within a One Health framework linking environmental and human health.

microbiology↗

bioRxiv2026

Tripeptidyl peptidase II is essential for maintaining cerebrovascular homeostasis of female mice and represents a novel therapeutic target for vascular dementia

Although cerebrovascular impairment is a known common driver of both Vascular dementia (VaD) and Alzheimers disease (AD), the underlying mechanisms remain poorly defined. Substantial evidence has demonstrated that brain-derived estrogen is essential for cerebrovascular health and neuroprotection. Consequently, therapeutic strategies that can replicate the beneficial effects of estrogen replacement therapy (ERT) in the brain while avoiding its peripheral risks are being actively pursued. Here, we demonstrate that tripeptidyl peptidase II (TPP2) is essential for cerebrovascular homeostasis in adult female mice by orchestrating intracellular Ca{superscript 2} distribution and local estrogen biosynthesis. Specifically, TPP2 deficiency triggers a vicious cycle of Ca{superscript 2} imbalance and estrogen deficiency, thereby disrupting the anticipatory unfolded protein response (UPR). This disruption consequently drives aberrant pexophagic flux and ultimately depletes ether-linked phosphatidylcholine (PC-O)--the essential building block of endothelial cell (EC) membranes. In addition, we identified PC-O as a key facilitator of choline uptake through FLVCR2 and therefore its deficiency causes subsequent choline depletion as well as significantly decreased acetylcholine (ACh). Consistent with the fact that choline is a building block of PC and that ACh is a primary driver of vascular dilation, TPP2 depletion leads to significant cerebrovascular degeneration characterized by narrowed lumens, decreased EC number, and abnormal aggregation of ECs within the blood vessel. Additionally, AAV-mediated specific expression of Far1 in ECs to promote ether-PC biosynthesis significantly increases cerebrovascular volume and diameter in hippocampi of adult female TPP2 knockout (T2KO) mice. Importantly, ectopic expression of Far1 in ECs not only significantly ameliorates memory impairment in global and conditional TPP2-depleted female mice, but also significantly improves memory performance of naturally aged female mice. In total, our findings establish TPP2 as a key determinant of cerebrovascular homeostasis in adult female mice, positioning it as a novel therapeutic candidate for the treatment of VaD and AD.

neuroscience↗

bioRxiv2026

BART-spatial unravels biologically significant transcriptional regulators from spatial omics data

Transcriptional regulators (TRs) are crucial regulators of cell fate decisions by activating or repressing lineage-specific genes and integrating environmental signals with intrinsic networks. Identifying functional TRs is essential for understanding development, tissue organization, and disease. Emerging spatial transcriptomics and epigenomics technologies now provide near- single-cell resolution mapping of genomic features while preserving information of each cells physical location and microenvironment which influence TR activity. Despite these advances, identifying active TRs in spatial data remains challenging due to low TR expression and the fact that TR activity often does not correlate directly with mRNA levels. Moreover, existing tools mainly designed for non-spatial single-cell data overlook spatial heterogeneity. To bridge this gap, we developed BART-spatial (Binding Analysis for Regulation of Transcription for spatial omics data), an innovative computational method to infer functional TRs from spatial omics data. BART-spatial integrates spatial variability and pseudotemporal information with publicly available TR binding profiles. Applied to multiple spatial datasets from diverse platforms, including 10x Visium, Visium HD, Atera, and spatial RNA-ATAC-seq, BART-spatial consistently outperforms existing methods, identifying state-specific TRs and revealing regulators undetectable by expression alone. Its compatibility with spatial epigenomics data further strengthens its utility and enables cross-validation. Overall, BART-spatial provides a powerful and robust tool for decoding spatially resolved gene regulatory programs.

bioinformatics↗

bioRxiv2026

Linking sugar sensing to immunity in plants via O-glycosylation

Interaction with microbes can reprogram metabolism and alter nutrient availability in plant cells. How metabolic changes modulate immune responses remains unknown. Here, we show that sugar-sensing O-glycosylation of immune-signaling kinases mediates metabolic regulation of immunity. Under sugar-replete conditions, the MAP kinase kinases (MKK4 and MKK5), key components of pattern-triggered immunity (PTI), are glycosylated with O-GlcNAc and O-fucose on their activation loops, blocking their phosphorylation by upstream kinases and thereby restricting PTI. Pathogen infection or sugar starvation reduces O-glycosylation of MKK4/5 and enhances immune signaling; these effects are reversed by GDP-fucose treatment, demonstrating that reduced sugar availability decreases O-fucosylation and enhances immune signaling in infected cells. Chemical inhibition of O-fucosylation enhances immunity and pathogen resistance in both Arabidopsis and tomato. Our findings establish O-glycosylation of MKKs as a metabolic rheostat that fine-tunes immune responses according to sugar availability during plant-microbe interactions, providing a new strategy for improving crop health.

plant biology↗

bioRxiv2026

Ammonium retention by Amberlite IRC-748 resin: useful for concentration assessments

Chelating ion exchange resins are widely used to eliminate metal interferences in the analysis of ammonium (NH4+) in soil extraction solutions. However, their potential to co-adsorb NH4+ remains underexplored. Here, synthetic metal ion solutions containing 6-30 mg L-1 NH4+ and the metal cations Ca2+, Mg2+, Cu2+, Mn2+, and Zn2+ were treated with Amberlite IRC-748 resin. The resin efficiently removed Ca2+ (-42.2%), Mg2+ (-21.1%), Cu2+ (-99.9%), Mn2+ (-56.9%), and Zn2+ (-93.6%). However, NH4+ losses of 2.2-5.6% were observed, indicating concentration-dependent co-adsorption. While these losses may be acceptable for concentration measurements via routine assays such as photometric analysis, they may still affect the accuracy of high-precision N analyses that rely on quantitative NH4+ recovery. This highlights a methodological caveat for resin-treated samples, especially in low-NH4+ environments. We therefore recommend including recovery assessments and correction factors when using chelating resins to improve accuracy in NH4+ quantification.

ecology↗

bioRxiv2026

Tree diversity intensifies soil microorganism-tree interactions

O_LIA productivity-driven higher nutrient demand of trees in diverse mixtures is frequently reported. Yet, it remains unclear how tree diversity influences microorganisms-plants interactions, in which microbes facilitate tree nutrient acquisition in exchange for carbon (C) to meet the resource demand of both. C_LIO_LIUsing a long-term tree diversity experiment in the subtropics, we assessed microbial investment in C-, nitrogen (N)-, and phosphorus (P)-acquiring enzymes in litter and mineral soil, testing the effects of tree species richness and mycorrhizal type (arbuscular (AM)- vs. ectomycorrhizal (EcM)-associated tree species). C_LIO_LIWith increasing tree species richness, microbial investment in C acquisition decreased, while investment in N and/or P acquisition increased in litter and in mineral soil. In mineral soil of AM-associated tree mixtures, ecoenzymatic stoichiometry revealed a shift from microbial investment in C toward P acquisition as tree species richness increased. C_LIO_LIOur findings suggest that tree diversity strengthens microbe-tree interactions in terms of C-for-nutrient exchange. This highlights the key role of soil microorganisms, particularly in AM symbiosis, shaping tree diversity-biogeochemical feedbacks. C_LI

ecology↗

bioRxiv2026

Architecture of the type II secretion system

The virulence of emerging Gram-negative pathogens frequently arises from toxins delivered by the type II secretion system1. Cryo-EM single particle analysis and cryo-electron tomography and have defined the outer membrane secretin pore in detail, but the organisation of proteins within the periplasm and inner membrane that form the pilus assembly platform is not well resolved2,3. Here we combine AlphaFold4 models with single particle cryo-EM to define the organisation of the pilus assembly platform. We show that CLM heterotrimers form a continuous link from the cytoplasmic ATPase, across the inner membrane and periplasm, to the base of the secretin channel. AlphaFold models of the inner membrane spanning rotor and cytoplasmic ATPase fit readily within the cryo-EM density. The resolved secretion system exhibits an offset between the inner membrane assembly platform and the outer membrane secretin pore, together with profound asymmetry and an unexpectedly open periplasmic architecture. This architecture provides a route by which large, folded proteins access the secretion channel from the periplasm and suggests that substrate engagement may trigger the final steps in secretion system assembly leading to secretion.

microbiology↗

bioRxiv2026

Salvianolic acids are natural senolytics and increase lifespan in old age

Cellular senescence plays a critical role in chronological aging and is implicated in the onset and progression of multiple age-related disorders. Targeting senescent cells represents a promising strategy to reduce disease burden and improve healthspan. Here we report the senotherapeutic properties of salvianolic acid (SA) family members, specifically A (SAA), B (SAB) and E (SAE). From a natural medicinal agent library, we identified selective cytotoxicity of these SA compounds against senescent cells across diverse senescence types and cell lineages. Mechanistically, SAA, SAB and SAE enhance ROS production and target glutathione S-transferase Pi1 (GSTP1), a redox homeostasis modulator, inducing both apoptosis and ferroptosis in senescent cells. Incorporation of SAs into chemotherapeutic regimens enhanced anticancer efficacy and prolonged post-treatment survival. Intermittent SA administration improved physical function and increased healthspan and lifespan in aged mice. Collectively, our study establishes SAs as an emerging class of natural senolytics (phenolic acids) with the capacity to delay aging and alleviate age-related pathologies in advanced life.

cell biology↗

bioRxiv2026

SPP1hi macrophages in fibrin niches promote hyperplastic tissue remodeling in rheumatoid arthritis synovium

In chronic inflammatory diseases, maladaptive tissue remodelling is driven by a complex interplay of resident cells, immune filtrates and the extracellular matrix. In the autoimmune disorder rheumatoid arthritis (RA), synovial tissue undergoes assive expansion to form an invasive pannus that drives the erosion of cartilage and bone. The mechanisms mediating this ggressive growth are incompletely defined. Using spatial transcriptomics profiling of patient tissue, we detected an bundance of proliferating fibroblasts near the synovial tissue lining surface and adjacent to SPP1hi macrophages. Notably, ese synovial lining regions were also distinctly marked by deposits of the clot-forming protein fibrin. While the SPP1hi acrophages phenotypically resemble pro-fibrotic macrophages that drive lung and liver fibrosis, these niches were devoid f the dense highly ordered collagen that marks fibrosis. Functionally, we found that SPP1hi macrophages degrade and hagocytose fibrin matrices and promote fibroblast proliferation. As fibrin provides transient matrices for de novo tissue eneration in the context of wound healing, these data support a model of hyperplastic tissue outgrowth involving SPP1hi acrophages, fibroblasts and fibrin matrices adhered to the exterior synovial tissue surface. While current RA therapies rimarily aim to dampen pro-inflammatory responses, our findings provide rationale for targeting pro-generative pathways nd SPP1hi macrophages. Once Sentence SummarySPP1hi macrophages in RA synovial fibrin deposits promote tissue hyperplasia.

immunology↗

bioRxiv2026

One-pot parallel Sidewinder construction from oligo pools

Reliable and cost-effective de novo DNA production at scale has become increasingly important to studying and engineering biology. Double-stranded DNA is constructed from short synthetic single-stranded DNA oligonucleotides synthesized either individually or as a pool. Oligonucleotide pools offer substantially reduced costs at the sacrifice of yield and individual oligo isolation, making efficient multiplexed DNA construction from pools a complex engineering challenge, yet one which promises to reduce cost, labor, and turnaround time if solved. Here we introduce Oligo Pool Sidewinder assembly, which enables one-pot, parallel assembly of hundreds of DNA fragments simultaneously into dozens of defined constructs with high fidelity from oligo pools. We pair a computational workflow for string-based bespoke oligo design with a set of construction rules for highly multiplexed assembly. We demonstrate recovery of individual sequences from the pool by construct-specific amplification with misconnection rates as low as 1 in 10. This high fidelity for connection enables hundreds of oligos to co-assemble in a single reaction. Further, we show universal amplification of libraries of defined target sequences in a single PCR and extend the approach through in vitro hierarchical assembly to construct a large 12.5-kilobase synthetic linear DNA product.

molecular biology↗

bioRxiv2026

From Generalist to Specialist: Evolution of PS2 α-integrins and Implications for Drug Targeting

Integrins are heterodimeric transmembrane receptors that mediate cell-cell and cell- extracellular matrix interactions and play essential roles in development and disease. Within the PS2 -integrin subfamily, four paralogs (IIb, 5, 8, and V) share a conserved RGD-binding motif yet exhibit diverse functional specializations. Integrins have been widely targeted therapeutically for various clinical conditions, though achieving subtype specificity remains a major challenge. Here, we performed an integrative evolutionary analysis of 114 PS2 -integrin sequences across 28 vertebrate species, combining phylogenetic reconstruction, time calibration, ancestral sequence inference, and structural mapping. Our time-calibrated phylogeny indicates that the PS2 lineage originated [~]862 Mya, with diversification of the four paralogs occurring prior to vertebrate radiation. Ancestral state reconstruction reveals that fibronectin and vitronectin binding are ancestral traits, whereas fibrinogen binding and {beta}3 pairing arose independently in the IIb and V lineage. Evolutionary rate analysis shows domain-specific divergence, with the {beta}-propeller acting as a hotspot of evolutionary change, likely driven by combined pressures from ligand binding and {beta}-subunit interaction. These pressures vary across paralogs: IIb exhibits accelerated evolution in ligand-binding regions, while V displays elevated rates in {beta}-subunit interaction domains. Mapping sequence variation onto structural interfaces identifies lineage-specific substitutions underlying functional divergence, including distinct molecular solutions for fibrinogen binding in IIb and V. These findings collectively demonstrate that PS2 -integrins evolved from a generalist ancestor through neofunctionalization and lineage-specific specialization. This work provides an evolutionary framework for identifying subtype-specific functional sites and highlights the potential of evolution-informed strategies to guide the development of more selective integrin-targeting therapeutics.

bioinformatics↗

bioRxiv2026

Gut microbiota-derived indole-3-propionic acid preserves dorsal hippocampal catecholamines to prevent post-stroke cognitive impairment

BackgroundGut dysbiosis has been increasingly implicated in post-stroke cognitive impairment (PSCI), yet the causal contribution and therapeutic potential of gut microbiota-derived metabolites remain unclear. This study aimed to identify key microbiota-derived metabolites involved in PSCI and to elucidate their underlying mechanisms. ResultsWe found that both PSCI patients and middle cerebral artery occlusion (MCAO) mice exhibited distinct gut microbial alterations, characterized by a marked reduction in tryptophan-metabolizing bacteria and indole-3-propionic acid (IPA), a gut microbiota-derived tryptophan metabolite. Exogenous IPA administration alleviated PSCI-like phenotypes in MCAO mice. Mechanistically, IPA preserved tyrosine hydroxylase-positive (Th) fibers and catecholamine levels in the dorsal hippocampus. Further analyses showed that IPA binds to the adaptor protein Ywhab, promotes ERK activation, and enhances neuronal survival, thereby counteracting neuronal apoptosis-associated inflammation and subsequent Th fiber degeneration. ConclusionThese findings identify IPA as a gut microbiota-derived neuromodulator that mitigates PSCI by preserving dorsal hippocampal catecholaminergic transmission. IPA may therefore serve as a promising predictive biomarker and therapeutic candidate for PSCI.

neuroscience↗

bioRxiv2026

Potential of HLA-E-targeting diabodies to induce lysis of HIV-1-infected cells by CD8+ T cells

A long-lived reservoir of cells harboring intact HIV-1 provirus persists throughout decades of antiretroviral therapy and can give rise to rapid viral rebound after treatment interruption. Some cure strategies employ cytotoxic T lymphocytes (CTL) to target this reservoir; however, the applicability and efficacy of immunotherapeutic strategies involving MHC class I-restricted CTL is limited by the polymorphic nature of MHC class I molecules and their downregulation by HIV-1 Nef. The non-polymorphic non-classical class I molecule HLA-E is stably expressed on HIV-1-infected CD4+ T cells and presents a potential universal target. We generated a single-chain diabody RLP-13 that redirects CTLs to target cells presenting a well-characterized peptide derived from Mycobacterium tuberculosis in the context of HLA-E. We verified the affinity and specificity of RLP-13. Through co-culture experiments, we confirmed that RLP-13 mediates polyfunctional, HLA-agnostic CTL responses. Using an HIV-1 reporter construct encoding the target peptide, we demonstrated robust and specific elimination of the HIV-1-expressing cell population. This proof-of-concept study shows that HLA-E antigens are promising immunotherapeutic targets that can bypass the limitations of classical MHC class I antigens - allelic variation and downregulation - and that such bispecific antibodies recognizing HIV-1-derived HLA-E binding epitopes could induce elimination of productively infected cells. SummarySengupta, Bachmann et al. utilize a novel HLA-E-restricted CD3-engaging single-chain diabody to induce antigen-specific polyfunctional CTL-responses that are HLA-type-independent. They further show that such biologics have potential to eliminate HIV-1-infected cells by targeting HLA-E-binding epitopes encoded in the HIV-1 provirus.

microbiology↗

bioRxiv2026

Holomycin from Yersinia ruckeri mediates fish infection at low temperature

Why microbes invest energy in producing structurally complex natural products at extremely low concentrations within hosts remains an important topic of interest in microbial ecology. This is because such compounds with potential "biomolecular activities" can reflect molecule-target interactions, thereby providing conceptual and mechanistic insights that inform the rational design of essential clinical agents. Here, we uncover the in situ ecological function of the dithiolopyrrolone antibiotic holomycin produced by the fish pathogen Yersinia ruckeri. We show that holomycins biosynthesis is strictly gated by low temperature and that trace amounts of holomycin accumulate in vivo during infection in rainbow trout. In addition, the holomycin-deficient mutant leads to markedly reduced virulence. Integrated multiomics, phenotypic analyses, and in vivo bioassay test reveal that holomycin is not a direct lethal factor but instead remodels host-associated microbiota and enhances Y. ruckeri biofilm formation. These coordinated effects promote pathogen colonization and infection progression. Our findings establish holomycin as a host-associated effector and illustrate how its existence and ecological function are mechanistically intertwined in the evolution of pathogenic bacterial chemical arsenals.

microbiology↗