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Probiotic Lacticaseibacillus casei 2S-1 Attenuates Escherichia coli-Induced Enteritis via Gut Microbiota Modulation and Host Gene Regulation.

Maintaining gut microbial homeostasis is crucial for host health, whereas infection with Escherichia coli (E. coli) is a major contributor to intestinal inflammation and microbial dysbiosis. Recent research has focused on probiotic strategies for managing enteric inflammatory disorders. Previous studies have shown that beneficial microorganisms show protection through modulating host immune responses, enhancing intestinal epithelial barrier integrity, and inhibiting pathogenic bacteria. To evaluate the prophylactic effectiveness of a recently isolated strain, Lacticaseibacillus casei 2S-1, in a murine model of E. coli-induced enteritis, this study focuses on interactions within the microbiota-intestinal-immune axis, together with host transcriptional responses and pathway enrichment associated with oxidative stress and mitochondrial function. In vitro analysis of probiotic features, including growth dynamics, acidogenic capacity, and tolerance to acidic and bile salt environments, as well as genetic safety profiling, followed the methodical isolation and taxonomic identification of L. casei 2S-1. A preventive intervention protocol was established, and a murine model of enteritis was induced by exposure to E. coli. Histopathological analyses were performed to observe in vivo safety and protective efficacy. Changes in gut microbial structure were characterized by 16S rRNA gene sequencing, while host responses were identified by intestinal immunohistochemistry and transcriptome profiling. L. casei 2S-1 showed probiotic properties. In vitro analyses showed that the strain exhibited tolerance to acidic and bile salt conditions, and its untreated culture supernatant showed antimicrobial activity against pathogenic bacteria. Its safety profile was supported by genomic analysis, which verified the lack of virulence-associated genes and antibiotic resistance factors. In vivo, L. casei 2S-1 pretreatment reduced mortality and intestinal inflammation, modulated gut microbial composition, and preserved intestinal barrier-associated protein expression in infected mice. This study provides experimental evidence supporting the prophylactic effects of L. casei 2S-1 and its associations with gut microbiota modulation and host transcriptional responses, providing a foundation for further investigation of probiotic-based preventive strategies against intestinal infections.

Animals

Leaf Rust in Rye: From Pathogen Biology to Host Defense and Resistance Breeding.

Leaf rust (LR), caused by Puccinia recondita f. sp. secalis (Prs), is considered one of the most dangerous rye (Secale cereale L.) diseases, causing yield losses exceeding 35%. This review summarizes all currently available data about this disease: pathogen characteristics (including its life cycle, natural variation, and disease symptoms), resistance resources, and the background of the plant immune response at the genome, transcriptome, and metabolome levels. The research conducted so far has allowed for the identification of dozens of genes that play a significant role in the rye immune response to Prs infection. Among them, genes encoding NBS-LRR proteins (including SECCE1Rv1G0014220, the most likely Pr3 candidate), glycosyltransferase, β-1,3-glucanase, 1-deoxy-D-xylulose 5-phosphate synthase, β-1,3-glucanase, UDP-glycosyltransferase, pathogenesis-related protein 1, ammonium transporter, and cytochrome P450 enzymes are candidates for seedling and all-stage resistance, whereas ScLr_ABC25 currently represents the most promising candidate associated with adult-plant resistance. Among the metabolites differentially accumulated in response to Prs, those related to phenylpropanoids, diterpenoids, and thiamine branches seem to play the most important role in the immune response. Finally, we suggest how the knowledge acquired so far about the rye-Prs interaction can be used in modern breeding programs aimed at obtaining cultivars with enhanced resistance to LR, such as through the use of functional gene markers and/or metabolic biomarker-assisted selection and, in the more distant future, by developing and applying new genomic techniques for precise editing of resistance and susceptibility genes, engineering synthetic immune receptors and decoys, and pan-genomic exploration for identification of rare or lineage-specific resistance alleles. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Plant Diseases

Single-cell RNA sequencing defines developmental progression and reproductive transitions of Pneumocystis carinii.

UNLABELLED: Pneumocystis species are host-obligate fungal pathogens that cause severe pneumonia in immunocompromised individuals. Despite their clinical importance, their life cycle remains poorly understood, in part because Pneumocystis depends on the host environment for most nutrients and requires sexual reproduction for survival, which occurs exclusively in vivo. This study presents the first single-cell RNA sequencing (scRNA-seq) atlas of Pneumocystis carinii, generated from isolated organisms recovered from the bronchoalveolar lavage fluid of infected rats to map the life cycle of P. carinii. Transcriptomes from 87,716 cells were analyzed using the 10× Genomics platform, revealing 13 transcriptionally distinct clusters representing key developmental stages, including biosynthetically active trophic forms, mating-competent intermediates, and asci undergoing sporulation. These states were characterized by expression of MAPK signaling components, β-glucan-modifying enzymes, and spore-associated genes, respectively. The scRNA-seq data support previous evidence that these host-obligate fungi undergo sexual reproduction and provide new insights into the gene expression patterns associated with different life cycle phases. Biomarkers associated with ascus formation identified by scRNA-seq were validated by RT-qPCR, showing decreased expression levels in ascus-depleted populations treated with anidulafungin, a drug that halts ascus formation. More broadly, this approach provides a strategy for studying the full life cycles of fungal pathogens that cannot be continuously cultured. IMPORTANCE: Pneumocystis species (spp.) are clinically significant fungal pathogens that cannot be sustainably cultured in vitro due to their host-obligate nature. This longstanding limitation has impeded progress in understanding their life cycle and identifying therapeutic vulnerabilities. Here, we apply scRNA-seq to P. carinii isolated directly from infected rat lungs, generating the first transcriptional map of its developmental progression. Our results define discrete gene expression states associated with trophic growth, mating activation, and ascus formation and provide transcriptional evidence for a structured life cycle, clarifying key developmental transitions and identifying potential regulatory targets for therapeutic intervention. Importantly, this study demonstrates that scRNA-seq can resolve the developmental biology of host-restricted fungal pathogens that cannot be cultured in vitro. This approach offers a generalizable framework for investigating other unculturable or obligate microbial pathogens directly within their native host environments, where traditional experimental tools are limited.

Pneumocystis carinii

Comprehensive Viral Detection and Profiling of Plasma Cell-Free RNA in Patients With Suspected Hemophagocytic Lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a severe, rapidly progressive disease. While viral infection is considered a common etiology of pediatric HLH, specific causative viruses other than the Epstein-Barr virus (EBV) have been rarely identified. This study utilized metagenomic next-generation sequencing (NGS) to identify potential causative pathogens in plasma samples from 17 pediatric patients with suspected HLH. Additionally, one case each of confirmed EBV- and cytomegalovirus (CMV)-associated HLH was analyzed for methodological validation. Plasma cell-free RNA (cfRNA) profiling was performed using NGS data to assess the host transcriptome response. Significant viral reads of human herpesvirus-6B, human herpesvirus-7, and Hubei reo-like virus (HRLV) 14 were detected using metagenomic NGS in one patient each. Plasma cfRNA profiles from five patients with viral infection (including EBV and CMV) were compared to those of 14 patients without viral infection. By comparing the two patient groups, 1053 differentially expressed genes were identified. The gene ontology (GO) term of "adaptive immune response" (GO: 0002250) was significantly enriched among upregulated genes in the virus-positive group. Furthermore, an isolated cluster consisting specifically of mitochondrial RNAs, was identified in the upregulated genes of the virus-positive group. Using metagenomic NGS, several candidate viral pathogens were identified in patients with suspected infection-related HLH. The viral genome of HRLV 14, previously undetected in human clinical samples, was identified in one patient. The results from plasma cfRNA profiling suggest that mitochondrial RNAs may reflect the underlying pathogenesis of virus-associated HLH and have potential utility as disease biomarkers.

Humans

Stepping out of the dark: how metabolomics shed light on fungal biology.

Metabolomics, a critical tool for analyzing small-molecule metabolites, integrates with genomics, transcriptomics, and proteomics to provide a systems-level understanding of fungal biology. By mapping metabolic networks, it elucidates regulatory mechanisms driving physiological and ecological adaptations. In fungal pathogenesis, metabolomics reveals host-pathogen dynamics, identifying virulence factors like gliotoxin in Aspergillus fumigatus and metabolic shifts, such as glyoxylate cycle upregulation in Candida albicans. Ecologically, it highlights fungal responses to abiotic stressors, including osmolyte production like trehalose, enhancing survival in extreme environments. These insights highlight metabolomics' role in decoding fungal persistence and niche colonization. In drug discovery, it aids target identification by profiling biosynthetic pathways, supporting novel antifungal and nanostructured therapy development. Combined with multi-omics, metabolomics advances insights into fungal pathogenesis, ecological interactions, and therapeutic innovation, offering translational potential for addressing antifungal resistance and improving treatment outcomes for fungal infections. Its progress shed light on complex fungal molecular profiles, advancing discovery and innovation in fungal biology.

Metabolomics

Epigenetic and metabolic reprogramming of innate immune cells establishes immunological memory in the Schistosomiasis vector snail Biomphalaria glabrata.

Innate immune memory enables non-vertebrates to mount faster and more effective immune responses upon re-exposure to a previously encountered pathogen, yet its cellular and molecular bases remain poorly understood. The freshwater snail Biomphalaria glabrata, intermediate host of the human parasite Schistosoma mansoni, provides a powerful model to investigate this phenomenon. Here, we show that innate immune memory in B. glabrata is carried by hemocytes and relies on profound metabolic and epigenetic reprogramming initiated during primary infection. Using an integrative multi-omics approach combining transcriptomics, chromatin accessibility profiling, whole-genome bisulfite sequencing and targeted metabolomics, we reveal that the first parasite encounter induces a stable rewiring of hemocyte metabolism and chromatin landscape. This reprogramming primes hemocytes for a massive and rapid transcriptional response upon secondary challenge, characterized by an immune shift toward highly specific humoral effector pathways. Metabolic analyses demonstrate an early switch toward aerobic glycolysis, altered tricarboxylic acid cycle activity and amino acid metabolism, consistent with a Warburg-like metabolic state previously described in vertebrate trained immunity. Notably, metabolic and epigenetic remodeling occurs primarily during the primary infection and remains stable upon secondary exposure, suggesting that immune memory is encoded prior to pathogen re-encounter. Together, our results identify conserved metabolic and epigenetic mechanisms underlying innate immune memory in a non-vertebrate host and provide direct evidence that hemocyte-mediated innate immune memory in B. glabrata shares core features with trained immunity described in vertebrates.

Animals

Microbial DNA analysis of paired blood-bronchoalveolar lavage fluid in post-HSCT patients with pneumonia implying application conditions of blood as a surrogate in pathogen detection.

BACKGROUND: Blood testing aids pneumonia diagnosis, but its effectiveness varies. Given the invasiveness of bronchoalveolar lavage fluid (BALF) sampling versus blood testing's simplicity, this study investigates when blood can reliably substitute for BALF in detecting microbial presence, especially for pathogens. RESULTS: Metagenomic sequencing was performed on paired BALF-blood samples from 21 post-HSCT immunocompromised (ICP) and 21 immunocompetent (ICT) patients. The ICP cohort was expanded to 62 for biomarker validation. Host responses were profiled via metatranscriptomics (30 BALF samples). Microbial alpha and beta diversity differed significantly between blood and BALF in ICP, but not ICT, patients. ICP patients' BALF contained a greater diversity and abundance of microbes. A higher proportion of microbial DNA sequences in ICP patients' blood was also present in their BALF, suggesting a potentially more permeable alveolar-capillary barrier. Related genes (e.g., NABA CORE MATRISOME, extracellular matrix organization, cell-cell adhesion) were downregulated. Upregulated pathways like VEGFA-VEGFR2 signaling and Rho GTPases suggested increased vascular permeability. In ICP patients, 419 microbial sequences in blood indicated their presence in the lower respiratory tract with > 70% certainty. CONCLUSION: Host immune status significantly influences blood-BALF microbial diversity differences. Shared blood-BALF microbial DNA sequences show potential for aiding pneumonia pathogen diagnosis, offering a novel biomarker identification approach.

Humans

Typhoid Toxin of Salmonella enterica Induces ISG15 Responses Mediating Host Cell Survival and Counteracting Intracellular Infection.

The typhoid toxin is a secreted virulence factor of typhoidal serovars of the bacterial pathogen Salmonella enterica implicated in typhoid fever and chronic infections. The toxin causes a DNA damage response in human cells, characterised by cell-cycle arrest and cellular distension, resulting in cellular senescence and increased bacterial burden. To better understand host responses to typhoid toxin, we performed a transcriptomic analysis of intoxicated host cells and found that the toxin induced expression of genes relating to the type-I interferon response, including the ubiquitin-like protein ISG15. ISG15 was upregulated in a STING-dependent manner, reduced bacterial burden, and was found to be critical to host cell survival in response to the typhoid toxin and interferon. This highlights ISG15 as an important component of the host cell defence to the typhoid toxin.

Humans

Convergent methodologies in prosthetic joint infection research: integrating transdisciplinary approaches to understand and prevent biofilm-driven failure of orthopaedic prostheses.

Prosthetic joint infections (PJIs) remain among the most devastating complications of arthroplasty, imposing substantial clinical, economic and patient burdens. Although culture-based diagnostics underpin current clinical practice, PJIs are biofilm-driven infections shaped by taxonomic diversity, spatial organization, host responses and surface interactions, meaning conventional approaches provide only a partial and often decontextualized view of the infection process. We examine how convergent methodologies can transform PJI research by integrating approaches that have traditionally been studied in isolation, including sequencing, transcriptomics, metabolomics, advanced imaging and culture-based characterization. We discuss how whole-genome sequencing, shotgun metagenomics, transcriptomic and metabolomic approaches resolve pathogen identity, functional activity and adaptive persistence and how cross-scale imaging and spatial biology techniques reveal where microbes colonize, interact and survive across implant surfaces. We highlight emerging opportunities to unify these datasets into coherent frameworks that capture both the molecular and physical dimensions of PJIs. Integrating these complementary approaches will enable a multi-layered understanding of PJIs that link composition, function and spatial organization. Ultimately, this provides a foundation for predictive diagnostics, precision antimicrobial strategies and improved implant design and supports a shift towards more effective, mechanism-informed management of implant-associated infection.

Prosthesis-Related Infections

Biocontrol effect of a solid-state fermentation-derived extract mixture of Trichoderma asperellum on sunflower Sclerotinia rot and associated host defense responses.

Sclerotinia disease is a destructive fungal disease of sunflowers, soybeans, and other economically important crops, causing substantial yield loss and quality deterioration. Long-term reliance on dose-dependent broad-spectrum fungicides is constrained by resistance risks and potential environmental burdens, creating tension with the sustainability goal of "reducing pesticide use while improving efficacy." Here, we explore a Trichoderma spp.-based microbial disease management strategy. Whole-genome sequencing of Trichoderma asperellum TCS007 isolated from Antarctic marine sediments, coupled with genome mining, predicted diverse biosynthetic gene clusters putatively associated with siderophores, polyketides, nonribosomal peptides, and terpenoids; the corresponding metabolites are not chemically confirmed and require further validation. Using a solid-state fermentation workflow, we prepared a fermentation-derived extract mixture (TCS007-SSF-Ex). In vitro assays showed dose-dependent inhibition of Sclerotinia sclerotiorum by TCS007-SSF-Ex (EC50 = 1.252 mg/L), and microscopy revealed cellular damage-consistent changes, including organelle disruption and plasmolysis. Pathogen transcriptomic and metabolism-related analyses indicated broad perturbations in organelle biogenesis and metabolic processes, with significant alterations in pathways associated with succinate, D-glucose, and phenylacetate; these results are consistent with growth inhibition and reduced pathogenicity, but specific molecular targets and causal links remain to be validated. In vivo, under certain application conditions, triple applications increased APX activity (+492.5%) and β-1,3-glucanase activity (+419.6%). Collectively, this work supports a "pathogen suppression-host defense induction" framework and facilitates subsequent identification of active components and mechanistic validation.IMPORTANCESclerotinia diseases cause recurrent and economically important losses in oilseed crops, while long-term fungicide use is constrained by resistance risks and environmental burdens. Trichoderma-based biocontrol is a promising complementary strategy, yet evidence supporting metabolite-containing Trichoderma-derived preparations as immune elicitors remains less consolidated than that for living inoculants, and scalable production routes are still needed. Here, we examine an Antarctic marine sediment-derived strain, Trichoderma asperellum TCS007, and a solid-state fermentation (SSF)-derived extract mixture (TCS007-SSF-Ex) produced via solid-state fermentation. We combine in vitro antifungal assays, pathogen ultrastructural observations, and correlative omics analyses with in vivo measurements of sunflower defense enzymes (APX and β-1,3-glucanase) to evaluate a "pathogen suppression-host defense induction" framework. Our findings support the potential of SSF-derived Trichoderma metabolite mixtures for greener management of Sclerotinia disease and provide a foundation for future chemical identification of active components and mechanistic validation.

Ascomycota

Recent Advances in the Comprehension of Molecular and Genetic Mechanisms Underlying Yeast Biocontrol Efficacy Against Fungal Pathogens in Agriculture.

Recent advances in biotechnologies have enabled scientists to uncover biological processes across multiple research fields. Still, the molecular and genetic mechanisms underlying the biological control efficacy of yeast biocontrol agents (YBCAs) against fungal plant pathogens remain incompletely elucidated. This review focuses on recent insights into the regulatory bases and molecular interplay underlying successful disease control by YBCAs. It provides a detailed description of core antagonistic molecular mechanisms-nutrient and iron competition, mycoparasitism via cell wall degradation, antifungal compounds production, oxidative stress resistance, biofilm formation and colonization, and induction of the host defense responses-and integrates genomic, transcriptomic, proteomic, and metabolomic evidence to elucidate each mechanism. Further, how genetic engineering-based approaches that leverage omics data and functional genetics can help overcoming obstacles to translate YBCAs efficacy from laboratory conditions to the field are also discussed. Finally, the use of the CRISPR-Cas technology is recommended to better exploit how master transcription factors coordinate multiple mechanisms simultaneously; these factors are crucial for the synergistic antifungal effect, which is critical for developing highly effective YBCAs. Ultimately, the mechanism-based perspective provides a unified conceptual framework for understanding YBCAs efficacy and can guide the rational design of next-generation biocontrol agents for sustainable agriculture.

CRISPR-Cas technology

Diverse RNA viruses discovered in multiple seagrass species.

Seagrasses are marine angiosperms that form highly productive and diverse ecosystems. These ecosystems, however, are declining worldwide. Plant-associated microbes affect critical functions like nutrient uptake and pathogen resistance, which has led to an interest in the seagrass microbiome. However, despite their significant role in plant ecology, viruses have only recently garnered attention in seagrass species. In this study, we produced original data and mined publicly available transcriptomes to advance our understanding of RNA viral diversity in Zostera marina, Zostera muelleri, Zostera japonica, and Cymodocea nodosa. In Z. marina, we present evidence for additional Zostera marina amalgavirus 1 and 2 genotypes, and a complete genome for an alphaendornavirus previously evidenced by an RNA-dependent RNA polymerase gene fragment. In Z. muelleri, we present evidence for a second complete alphaendornavirus and near complete furovirus. Both are novel, and, to the best of our knowledge, this marks the first report of a furovirus infection naturally occurring outside of cereal grasses. In Z. japonica, we discovered genome fragments that belong to a novel strain of cucumber mosaic virus, a prolific pathogen that depends largely on aphid vectoring for host-to-host transmission. Lastly, in C. nodosa, we discovered two contigs that belong to a novel virus in the family Betaflexiviridae. These findings expand our knowledge of viral diversity in seagrasses and provide insight into seagrass viral ecology.

RNA Viruses

Venomous Lepidoptera: defensive toxin systems, venom composition, and clinical significance.

Venomous Lepidoptera constitute an underrecognized yet medically significant group of toxin-producing arthropods that employ contact-mediated defensive envenomation through specialized integumentary structures such as setae, spines, and scoli. Unlike actively stinging arthropods, these insects deliver venom passively upon contact, eliciting a diverse spectrum of clinical manifestations collectively termed lepidopterism. Clinical outcomes range from localized pain and dermatitis to severe systemic effects, including hemorrhagic syndromes, complement activation, and chronic inflammatory disorders. Recent advances in proteomic and transcriptomic technologies have transformed our understanding of lepidopteran venoms, revealing unexpectedly complex toxin repertoires comprising serine proteases, phospholipases, pore-forming proteins, disulfide-rich peptides, neuroactive RF-amide peptides, and immune-modulating components. These findings have provided new insights into the molecular basis of toxicity, host-pathogen interactions, and the evolutionary diversification of venom systems within Lepidoptera. This review synthesizes current knowledge on the morphology of venom-delivery structures, venom composition, mechanisms of action, and associated clinical manifestations, while highlighting medically important taxa, particularly species of the genus Lonomia. The successful development of antivenom against Lonomia envenomation underscores the translational relevance of lepidopteran toxin research and its potential for therapeutic innovation. By integrating molecular, clinical, and evolutionary perspectives, this review repositions venomous Lepidoptera as a legitimate and important component of arthropod toxinology. Furthermore, it identifies critical methodological limitations and key knowledge gaps, providing a framework for future investigations aimed at advancing our understanding of toxin biology, immunopathology, and the development of novel biomedical applications.

Animals

A Leucine-Rich Repeat Receptor-Like Protein Associated with a QTL for Septoria Stem Canker in Populus trichocarpa × Populus deltoides Hybrid Poplar.

The fungal plant pathogen Sphaerulina musiva (Ascomycota) causes Septoria stem canker, the most economically damaging disease of Populus plantations in North America, yet the genetic determinants of host resistance remain uncharacterized in hybrid poplar. Using an inoculation experiment with the 52-124 pseudo-backcross family of Populus trichocarpa × Populus deltoides (TD × D) hybrid poplar, a single significant QTL was identified on Chromosome 16 (LOD = 4.93) associated with both stem canker count and disease severity score. Transcriptomic analysis of two resistant and two susceptible genotypes across a 72-hour infection time course identified a single differentially expressed gene within the QTL candidate gene window: Podel.16G125900, a putative leucine-rich repeat receptor-like protein (LRR-RLP) with homology to receptor-like protein 33 in Arabidopsis thaliana. Podel.16G125900 is located 3001 bp (0.019 cM) upstream of the QTL peak and showed a strong infection-induced upregulation in susceptible genotype 852 (log2 fold-change = 20.47) and higher baseline expression in resistant genotypes relative to susceptible genotypes across all infection time points, consistent with a resistance mechanism in which expression level contributes to the degree of resistance conferred. Two P. trichocarpa homologs were not differentially expressed and differ substantially in sequence content, suggesting the resistance function is specific to the resistant P. deltoides lineage. These findings identify Podel.16G125900 as a strong candidate gene underlying quantitative resistance mechanisms modulating Septoria stem canker resistance in the 52-124 family of TD × D hybrid poplar and provide a target for future functional validation and marker-assisted resistance breeding.

Disease Resistance

Droplet-Based Single-Cell 3' mRNA Sequencing of Marburg Virus-Infected Samples.

Single-cell technologies are continually evolving with emerging methods that are gradually uncovering the central DNA-RNA-protein dogma. Single-cell RNA sequencing is one arm of a multi-omic approach that achieves an astounding level of granularity to reveal the complexity of virus-host interactions at the transcriptomic level. Cell tropism, virus replication, pathogenesis, and gene expression changes mediated by the virus and the host's immune response to infection are just some areas of study that are gaining better clarity due to the high-resolution analysis afforded by the technology.We describe a single-cell sequencing protocol for Marburg virus infection in vivo using nonhuman primate blood and the 10× Chromium Next GEM single-cell genomics methodology. Working with pathogens of high consequence is logistically complicated, requiring containment in biosafety level (BSL)-4 laboratories and harsh inactivation procedures before samples can safely be removed to lower biosafety conditions. We provide procedural insight into sample isolation and processing conducted in BSL-4 and describe the requirements for safe sample removal without jeopardizing quality for down-stream sequencing and analysis in BSL-2 conditions. Characterization of complicated biological processes mediated by high-containment pathogens, typically restricted to analogous model systems, e.g., minigenome, can be achieved using live virus.

Animals

Spore type-specific gene expression profiles underlying development and leaf infection processes of Colletotrichum graminicola.

Colletotrichum graminicola causes significant losses of the staple crop maize worldwide. The fungus produces two distinct asexual spore types, oval and falcate conidia, which show unique processes in development and plant interaction. Based on genome resequencing of our laboratory strain (CgM2/M1.001), we investigated the gene expression profiles of oval and falcate conidia during development and early leaf infection using RNA-seq. Our results reveal specific gene expression profiles between the two spore types, indicating fundamental differences in their developmental programs that reflect different modes of infection. We identified expression patterns discriminating both conidia types from mycelium and spore type-specific ones for genes encoding transcription factors, conserved fungal developmental genes, transporters, genes of secondary metabolite clusters, and pathogenicity-related functions, including effectors and carbohydrate-active enzymes (CAZymes). Our study shows that despite the identical genomic basis, oval and falcate conidia show unique transcriptomes across vegetative development and early plant interaction. Taking together, these results provide new insights into the molecular mechanisms determining the biology of C. graminicola and its interaction with the plant host.

Colletotrichum graminicola

Outbreaks of fluconazole-resistant Candida parapsilosis are driven by low-biofilm-producing isolates that emerge under host selection.

Candida parapsilosis is a major human fungal pathogen, with recent global outbreaks driven by fluconazole-resistant (FLCR-Cp) isolates that are difficult to eradicate and associated with poor clinical outcomes. However, the microbial traits enabling persistence of these outbreak lineages remain poorly defined. Here, we show that FLCR-Cp isolates responsible for prolonged, multi-country outbreaks consistently exhibit a striking low-biofilm-producing (LBP) phenotype. Contrary to the prevailing view that robust biofilm formation promotes persistence, LBP strains displayed enhanced stress tolerance, increased cell wall masking, and reduced immune recognition. These traits conferred resistance to neutrophil and macrophage killing and enhanced survival in immune cell-rich organs during systemic infection. Genome-wide transcriptomic profiling revealed extensive metabolic and regulatory rewiring in LBP strains. Whole-genome sequencing (WGS) of a global isolate collection further demonstrated that the LBP phenotype has emerged independently multiple times, supporting convergent evolution under host selection. Functional genomic analyses suggest that biofilm attenuation arises through multigenic changes, and disruption of key biofilm-associated transcriptional regulators enhanced fitness during immune interactions. Together, our findings overturn the assumption that robust biofilm formation drives outbreak persistence and instead identify biofilm attenuation as an adaptive tradeoff that promotes immune evasion and long-term survival. These results redefine our understanding of C. parapsilosis adaptation during healthcare-associated outbreaks and shift attention toward host-driven evolutionary processes than environmental persistence alone.

Biofilms

Host immunological response of Ross 308 broilers fed an anti-IL-10 antibody to Eimeria and Clostridium perfringens challenge.

Understanding host response mechanisms may lead to improved management of poultry diseases such as necrotic enteritis. Ross 308 broilers (20 birds/cage, 32 cages) received diets &#xb1; anti-interleukin-10 (IL-10) antibody, an intervention to improve immune activation, in three experimental replicates (R1, R2, R3). R1 and R2 received 1 &#xd7; 108 colony forming units (CFU) Salmonella Typhimurium on day (d) 1. On d 14, birds were assigned to unchallenged control or 15,000 sporulated Eimeria maxima oocyst gavage challenge, with a subset receiving E. maxima + Clostridium perfringens (1 &#xd7; 10&#x2078; CFU d 18-19) to induce necrotic enteritis. Intestinal tissue and digesta samples were collected from 6 birds/treatment at baseline (d 14), peak infection (d 21), and post-peak infection (d 25) to measure luminal IL-10 (ELISA), interferon gamma (IFN&#x3b3;) via immunohistochemistry, and IL-10, CD4, CD8, CD25, and KUL01 via RNAscope. Data were analyzed via two-way ANOVA (P &#x2264; 0.05). In R3, baseline duodenal IL-10 was 458 ng/mg protein greater in birds fed the control diet, while E. maxima + C. perfringens inoculation increased jejunal and ileal IL-10 content by 528 and 649 ng/mg protein at peak infection (P < 0.05). In R2, peak jejunal tissue % IL-10 area increased during E. maxima + C. perfringens challenge (P < 0.05). Baseline and peak jejunal R3 RNA was sequenced on an Illumina NovaSeq 6000, mapped to the chicken genome, and differential expression identified with DESeq2 (|log&#x2082; fold change| > 1; FDR &#x2264; 0.05). At peak, E. maxima challenge overrepresented genes involved in cell cycle, lipid metabolism, and B cell proliferation (P < 0.002), while E. maxima + C. perfringens overrepresented defense response and catabolic process terms (P < 0.0001). Sex altered the host immune response to challenge (P < 0.05), while E. maxima &#xb1; C. perfringens induced a similar host immune response regardless of dietary anti-IL-10. Overall, pathogenic challenge status was the primary driver of host immune response with the effect of anti-IL-10 antibody influenced by S. Typhimurium.

Clostridium perfringens