{"title":"Eubacterium limosum modulates tumor microenvironments and produces antitumor metabolites active against colorectal cancer.","authors":"Yao Lu,Ruiting Lan,Qianhua Fan,Huijing Tang,Dalong Hu,Shuwei Zhang,Xiaoying Lin,Ruoshi Wang,Ruiqing Zhao,Hui Sun,Liyun Liu,Jianguo Xu","doi":"10.1093/ismejo/wraf130","DOIUrl":"https://doi.org/10.1093/ismejo/wraf130","url":null,"abstract":"None declared.Conflicts of interestGut microbiota play a key role in ameliorating colorectal cancer (CRC). Eubacterium limosum is a potential probiotic with anti-CRC functions. However, the mechanistic basis of the anti-CRC effect remains largely unknown. In vitro, we detected the effects of the E. limosum strain El1405 on cell proliferation, colony formation, cell cycle, and apoptosis of CRC cells, and found that El1405CS specifically suppressed cell proliferation by altering cell cycle distribution and inducing apoptosis. In the CT26 syngeneic mouse model, daily gavage with live El1405, inactivated El1405, culture supernatant of El1405, and El1405-derived indole derivatives, including indole-3-lactic acid (ILA), indole-3-acetic acid (IAA), L-arginine, and butyrate, inhibited tumor growth. Analysis of the 16S rRNA gene sequences revealed that El1405 altered the microbiota compositions within tumors, primarily reducing the abundance of Enterobacter, Pseudomonas, and Staphylococcus. Staphylococcus succinus isolated from the tumors of CT26 syngeneic mice promoted abdominal metastasis of tumors. Moreover, El1405 intervention significantly increased the levels of TNF-α, INF-γ, and CD8 in the tumor microenvironment, while decreasing the levels of CD4, IL-6, IL-10, and TGF-β. Metabolomic analysis indicated that El1405 induced antitumor effects through changing the serum metabolome of mice by producing indole derivatives such as ILA and IAA. Furthermore, 16S rRNA gene sequencing demonstrated that El1405 intervention changed the composition of intestinal flora, significantly increasing the abundance of Roseburia and Eubacterium while decreasing the abundance of Staphylococcus and Enterococcus. These findings suggest that E. limosum El1405 is a potential probiotic candidate for the prevention of CRC.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-26DOI: 10.1093/ismejo/wraf131
Olivia F Schakel,Ryan K Fritts,Anthony J Zmuda,Sima Setayeshgar,James B McKinlay
{"title":"Microbial cross-feeding stabilized by segregation of a dependent mutant from its independent ancestor.","authors":"Olivia F Schakel,Ryan K Fritts,Anthony J Zmuda,Sima Setayeshgar,James B McKinlay","doi":"10.1093/ismejo/wraf131","DOIUrl":"https://doi.org/10.1093/ismejo/wraf131","url":null,"abstract":"Microbial gene loss is hypothesized to be beneficial when gene function is costly, and the gene product can be replaced via cross-feeding from a neighbor. However, cross-fed metabolites are often only available at low concentrations, limiting the growth rates of gene-loss mutants that are dependent on those metabolites. Here we define conditions that support a loss of function mutant in a three-member bacterial community of (i) N2-utilizing Rhodopseudomonas palustris as an NH4+-excreting producer, (ii) N2-utilizing Vibrio natriegens as the ancestor, and (iii) a V. natriegens N2-utilizaton mutant that is dependent on the producer for NH4+. Using experimental and simulated cocultures, we found that the ancestor outcompeted the mutant due to low NH4+ availability under uniform conditions where both V. natriegens strains have equal access to nutrients. However, spatial structuring that increasingly segregated the mutant from the ancestor, while maintaining access to NH4+ from the producer, allowed the mutant to avoid extinction. Counter to predictions, mutant enrichment under spatially structured conditions did not require a growth rate advantage from gene loss and the mutant coexisted with its ancestor. Thus, cross-feeding can originate from loss-of-function mutations that are otherwise detrimental, provided that the mutant can segregate from a competitive ancestor.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"243 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-26DOI: 10.1093/ismejo/wraf132
Maria Valadez-Ingersoll, Hanny E Rivera, Jeric Da-Anoy, Matthew R Kanke, Kelly Gomez-Campo, M Isabel Martinez-Rugerio, Sebastian Metz, Michael Sweet, Julian Kwan, Ryan Hekman, Andrew Emili, Thomas D Gilmore, Sarah W Davies
{"title":"Cell type-specific immune regulation under symbiosis in a facultatively symbiotic coral","authors":"Maria Valadez-Ingersoll, Hanny E Rivera, Jeric Da-Anoy, Matthew R Kanke, Kelly Gomez-Campo, M Isabel Martinez-Rugerio, Sebastian Metz, Michael Sweet, Julian Kwan, Ryan Hekman, Andrew Emili, Thomas D Gilmore, Sarah W Davies","doi":"10.1093/ismejo/wraf132","DOIUrl":"https://doi.org/10.1093/ismejo/wraf132","url":null,"abstract":"Many cnidarians host single-celled algae within gastrodermal cells, yielding a mutually beneficial exchange of nutrients between host and symbiont, and dysbiosis can lead to host mortality. Previous research has uncovered symbiosis tradeoffs, including suppression of immune pathways in hosts, and correlations between symbiotic state and pathogen susceptibility. Here, we used a multiomic approach to characterize symbiotic states of the facultatively symbiotic coral Oculina arbuscula by generating genotype-controlled fragments of symbiotic and aposymbiotic tissue. 16S rRNA gene sequencing showed no difference in bacterial communities between symbiotic states. Whole-organism proteomics revealed differential abundance of proteins related to immunity, confirming immune suppression during symbiosis. Single-cell RNAseq identified diverse cell clusters within seven cell types across symbiotic states. Specifically, the gastrodermal cell clusters containing algal-hosting cells from symbiotic tissue had higher expression of nitrogen cycling and lipid metabolism genes than aposymbiotic gastrodermal cells. Furthermore, differential enrichment of immune system gene pathways and lower expression of genes involved in immune regulation were observed in these gastrodermal cells from symbiotic tissue. However, there were no differences in gene expression in the immune cell cluster between symbiotic states. We conclude that there is growing evidence for compartmentalization of immune system regulation in specific gastrodermal cells in symbiosis. This compartmentalization may limit symbiosis tradeoffs by dampening immunity in algal-hosting cells while simultaneously maintaining general organismal immunity.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-26DOI: 10.1093/ismejo/wraf129
Jianshu Zhao,Genevieve Brandt,Jessica L Gronniger,Zhao Wang,Jiaqian Li,Dana E Hunt,Luis M Rodriguez-R,Janet K Hatt,Konstantinos T Konstantinidis
{"title":"Quantifying the contribution of the rare biosphere to natural disturbances.","authors":"Jianshu Zhao,Genevieve Brandt,Jessica L Gronniger,Zhao Wang,Jiaqian Li,Dana E Hunt,Luis M Rodriguez-R,Janet K Hatt,Konstantinos T Konstantinidis","doi":"10.1093/ismejo/wraf129","DOIUrl":"https://doi.org/10.1093/ismejo/wraf129","url":null,"abstract":"Understanding how populations respond to disturbances represents a major goal for microbial ecology. While several hypotheses have been advanced to explain microbial community compositional changes in response to disturbance, appropriate data to test these hypotheses is scarce, due to the challenges in delineating rare vs. abundant taxa and generalists vs. specialists, a prerequisite for testing the theories. Here, we operationally define these two key concepts by employing the patterns of coverage of a (target) genome by a metagenome to identify rare populations, and by borrowing the proportional similarity index (PS index) from macroecology to identify generalists. We applied these concepts to time-series (field) metagenomes from the Piver's Island Coastal Observatory (PICO) to establish that coastal microbial communities are resilient to major perturbations such as tropical cyclones and (uncommon) cold or warm temperature events, in part due to the response of rare populations. Therefore, these results provide support for the insurance hypothesis [i.e., the rare biosphere has the buffering capacity to mitigate the effects of disturbance]. Additionally, generalists appear to contribute proportionally more than specialists to community adaptation to perturbations like warming, supporting the disturbance-specialization hypothesis [i.e., disturbance favors generalists]. Several of these findings were also observed in replicated laboratory mesocosms that aimed to simulate disturbances such as a rain-driven washout of microbial cells and a labile organic matter release from a phytoplankton bloom. Taken together, our results advance understanding of the mechanisms governing microbial population dynamics under changing environmental conditions and have implications for ecosystem modeling.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-14DOI: 10.1093/ismejo/wraf125
Cely T González, Christian Martin, Maddey Crane, Karen Gutierrez, Jacob Thomas, Lacy Remisoski, Maxwell Okros, Yousi Fu, Douglas V Guzior, Dustin Finkhouse, Christopher Bridges, Jenna Mielke, Gabriel Querido, Lienwil Padillo, Reda Girgis, Marc McClelland, Douglas Conrad, Xiaopeng Li, Robert A Quinn
{"title":"Microenvironmental Effects of a Non-Antibiotic Therapy for a Chronic Polymicrobial Infection Alter Microbial Physiology, Competition, and Virulence","authors":"Cely T González, Christian Martin, Maddey Crane, Karen Gutierrez, Jacob Thomas, Lacy Remisoski, Maxwell Okros, Yousi Fu, Douglas V Guzior, Dustin Finkhouse, Christopher Bridges, Jenna Mielke, Gabriel Querido, Lienwil Padillo, Reda Girgis, Marc McClelland, Douglas Conrad, Xiaopeng Li, Robert A Quinn","doi":"10.1093/ismejo/wraf125","DOIUrl":"https://doi.org/10.1093/ismejo/wraf125","url":null,"abstract":"People with cystic fibrosis (pwCF) have reduced mucociliary clearance in their airways, leading to the build-up of thick, sticky mucus susceptible to opportunistic infection. A new treatment, comprised of three small molecule drugs called Elexacaftor/Tezacaftor/Ivacaftor (ETI), has improved mucociliary clearance and lung function in pwCF, but how this therapy alters lung infections is poorly understood. This study experimentally modeled the biochemical changes in airway mucus caused by ETI to determine its effect on the CF lung microbiome structure and function. We prepared Artificial Sputum Medium (ASM) with reduced primary carbon sources (amino acids, deoxyribonucleic acid DNA, and mucin) to mimic the effects of ETI on mucus biochemistry due to improved mucociliary clearance and reduced pulmonary inflammation. The control and modified ASM were inoculated with pure CF pathogens or mixed-species communities and then grown in oxic and anoxic conditions, followed by multi-omics data analysis. Although oxygen strongly altered the community structure, the nutrient depletions in ASM had little effect. Instead, the reduced carbon sources altered the physiology of the collective community and its individual pathogens. This included modified growth kinetics in addition to altered nitrogen and nucleotide metabolism. Under reduced amino acid concentrations, a known effect of ETI on the sputum metabolome, the production of both Pseudomonas aeruginosa’s quinolones and rhamnolipids was significantly reduced. This indirect effect of ETI translates to reduced killing of competing pathogens and reduced toxicity to epithelial cells isolated from the airways of explanted human lung tissues. These findings indicate that ETI may provide further benefit to pwCF by reducing the competition and virulence of its principal pathogen and highlight how microenvironmental effects can have powerful impacts on polymicrobial infections.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144289802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-13DOI: 10.1093/ismejo/wraf111
Jamiema Sara Philip, Sehhaj Grewal, Jacob Scadden, Caroline Puente-Lelievre, Nicholas J Matzke, Luke McNally, Matthew A B Baker
{"title":"Mapping the loss of flagellar motility across the tree of life","authors":"Jamiema Sara Philip, Sehhaj Grewal, Jacob Scadden, Caroline Puente-Lelievre, Nicholas J Matzke, Luke McNally, Matthew A B Baker","doi":"10.1093/ismejo/wraf111","DOIUrl":"https://doi.org/10.1093/ismejo/wraf111","url":null,"abstract":"Bacterial swimming is mostly powered by the bacterial flagellar motor and the number of proteins involved in the flagellar motor can vary. Quantifying the proteins present in flagellar motors from a range of species delivers insight into how motility has changed throughout history and provides a platform for estimating from its genome whether a species is likely to be motile. We conducted sequence and structural homology searches for 54 flagellar pathway proteins across 11 365 bacterial genomes and developed a classifier with up to 95% accuracy that could predict whether a strain was motile or not. We then mapped the evolution of flagellar motility across the GTDB bacterial tree of life. We confirmed that the last common bacterial ancestor had flagellar motility and that the rate of loss of this motility was four-fold higher than the rate of gain. We showed that the presence of filament protein homologues was highly phylogenetically correlated with motility and that all species classified as motile contained at least one filament homologue. We calculated the rate of gain and loss for each flagellar protein and that the filament protein FliC was highly correlated with motility across the tree of life. We then measured the correlation of each flagellar motor protein with FliC and showed that the filament, rotor, and rod and hook proteins were all highly correlated with FliC, and thus with motility. We calculated the differential rates of gain and loss for each flagellar protein and quantified which genomes encoded for partial sets of flagellar proteins, indicating potential pathways by which motility could be lost. Overall, we show that filament, rod and hook and rotor proteins are conserved when flagellar motility is preserved and that the presence or absence of a FliC homologue is a good, simple predictor of whether or not a species has flagellar motility.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144278285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-13DOI: 10.1093/ismejo/wraf122
Estelle Pignon, Gábor Holló, Théodora Steiner, Simon van Vliet, Yolanda Schaerli
{"title":"Uptake and leakage rates differentially shape community arrangement and composition of microbial consortia","authors":"Estelle Pignon, Gábor Holló, Théodora Steiner, Simon van Vliet, Yolanda Schaerli","doi":"10.1093/ismejo/wraf122","DOIUrl":"https://doi.org/10.1093/ismejo/wraf122","url":null,"abstract":"Bacteria often grow as communities in intricate spatial arrangements on surfaces and interact with each other through the local exchange of diffusible molecules. Yet, our understanding of how these metabolite exchanges shape the properties of the communities remains limited. Here, we study synthetic communities of Escherichia coli amino acid auxotrophs interacting through the obligate exchange of amino acids. We genetically engineer these strains to alter their amino acid leakage and uptake abilities. We then characterise the spatial arrangement and composition of the communities when grown on a surface and compare these to qualitative predictions of a previously developed analytical model for cells growing in two dimensions. Our experiments provide empirical validation of the model’s central hypothesis: higher uptake rates reduce sector widths and promote mixing, while increased leakage rate of an amino acid increases the frequency of the strain benefiting from this amino acid. We thus extend the relevance of this simplified model to more complex, three-dimensional systems, while also identifying its limitations. Our findings provide critical insights into microbial community dynamics and establish a predictive framework for designing and engineering microbial consortia.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144278284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-09DOI: 10.1093/ismejo/wraf117
Francesco Ricci, Pok Man Leung, Tess Hutchinson, Thanh Nguyen-Dinh, Alexander H Frank, Ashleigh V S Hood, Vinícius W Salazar, Vera Eate, Wei Wen Wong, Perran L M Cook, Chris Greening, Harry McClelland
{"title":"Chemosynthesis enhances net primary production and nutrient cycling in a hypersaline microbial mat","authors":"Francesco Ricci, Pok Man Leung, Tess Hutchinson, Thanh Nguyen-Dinh, Alexander H Frank, Ashleigh V S Hood, Vinícius W Salazar, Vera Eate, Wei Wen Wong, Perran L M Cook, Chris Greening, Harry McClelland","doi":"10.1093/ismejo/wraf117","DOIUrl":"https://doi.org/10.1093/ismejo/wraf117","url":null,"abstract":"Photosynthetic microbial mats are macroscopic microbial ecosystems consisting of a wide array of functional groups and microenvironments arranged along variable redox gradients. Light energy ultimately drives primary production and a cascade of daisy-chained metabolisms. Heterotrophic members of these communities remineralise organic material, decreasing net primary production, and returning nutrients to the aqueous phase. However, reduced inorganic and one-carbon substrates such as trace gases and those released as metabolic byproducts in deeper anoxic regions of the mat, could theoretically also fuel carbon fixation, mitigating carbon loss from heterotrophy and enhancing net primary production. Here, we investigated the intricate metabolic synergies that sustain community nutrient webs in a biomineralising microbial mat from a hypersaline lake. We recovered 331 genomes spanning 40 bacterial and archaeal phyla that influence the biogeochemistry of these ecosystems. Phototrophy is a major metabolic potential found in 17% of the genomes, but over 50% encode enzymes to harness energy from inorganic substrates and 12% co-encode chemosynthetic carbon fixation pathways that use sulfide and hydrogen as electron donors. We experimentally demonstrated that the microbial community oxidises ferrous iron, ammonia, sulfide, and reduced trace gas substrates aerobically and anaerobically. Furthermore, carbon isotope assays revealed that diverse chemosynthetic pathways contribute significantly to carbon fixation and organic matter production alongside photosynthesis. Chemosynthesis in microbial mats results from a complex suite of spatially organised metabolic interactions and continuous nutrient cycling, which decouples carbon fixation from the diurnal cycle, and enhances the net primary production of these highly efficient ecosystems.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144237709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-07DOI: 10.1093/ismejo/wraf119
Alex S Grossman, Lei Lei, Jack M Botting, Jett Liu, Nusrat Nahar, Jun Liu, Jeffrey S McLean, Xuesong He, Batbileg Bor
{"title":"Saccharibacteria deploy two distinct type IV pili, driving episymbiosis, host competition, and twitching motility","authors":"Alex S Grossman, Lei Lei, Jack M Botting, Jett Liu, Nusrat Nahar, Jun Liu, Jeffrey S McLean, Xuesong He, Batbileg Bor","doi":"10.1093/ismejo/wraf119","DOIUrl":"https://doi.org/10.1093/ismejo/wraf119","url":null,"abstract":"All cultivated Patescibacteria, also known as the candidate phyla radiation, are obligate episymbionts residing on other microbes. Despite being ubiquitous in many diverse environments, including mammalian microbiomes, molecular mechanisms of host identification and binding amongst ultrasmall bacterial episymbionts remain largely unknown. Type 4 pili are well conserved in this group and could potentially facilitate these symbiotic interactions. To test this hypothesis, we genetically targeted pili genes in Saccharibacteria Nanosynbacter lyticus strain TM7x to assess their essentiality and roles in symbiosis. Our results revealed that Nanosynbacter lyticus assembles two distinct type 4 pili: a non-essential thin pilus that has the smallest diameter of any type 4 pili and contributes to host-binding and episymbiont growth; and an essential thick pilus involved in twitching motility. To understand the role of these pili in vivo we developed Saccharibacteria competition assays and species specific Fluorescence in situ hybridization probes. Competition between different Saccharibacteria within mock communities demonstrated consistent competitive outcomes that were not driven by priority effects but were dependent on the thin pilus. Collectively our findings demonstrate that Saccharibacteria encode unique extracellular pili that enable their underexplored episymbiotic lifestyle and competitive fitness within a community.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144237708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ISME JournalPub Date : 2025-06-02DOI: 10.1093/ismejo/wraf114
Yang Liu, Alexandra D Gates, Zhexian Liu, Quinn Duque, Sierra S Schmidt, Melissa Y Chen, Corri D Hamilton, George A O’Toole, Cara H Haney
{"title":"In vitro biofilm formation by a beneficial bacterium partially predicts in planta protection against rhizosphere pathogens","authors":"Yang Liu, Alexandra D Gates, Zhexian Liu, Quinn Duque, Sierra S Schmidt, Melissa Y Chen, Corri D Hamilton, George A O’Toole, Cara H Haney","doi":"10.1093/ismejo/wraf114","DOIUrl":"https://doi.org/10.1093/ismejo/wraf114","url":null,"abstract":"Plant roots form associations with beneficial and pathogenic soil microorganisms. Although members of the rhizosphere microbiome can protect against pathogens, the mechanisms are poorly understood. We hypothesized that the ability to form a biofilm on the root surface is necessary for the exclusion of pathogens; however, it is not known if the same biofilm formation components required in vitro are necessary in vivo. Pseudomonas brassicacearum WCS365 is a beneficial strain that is phylogenetically closely related to an opportunistic pathogen Pseudomonas sp. N2C3 and confers protection against N2C3 in the rhizosphere. We used this plant-mutualist-pathogen model to screen collections of P. brassicacearum WCS365 increased attachment mutants (iam) and surface attachment defective (sad) transposon insertion mutants that form increased or decreased biofilm on abiotic surfaces, respectively. We found that whereas the P. brassicacearum WCS365 mutants had altered biofilm formation in vitro, only a subset of these mutants lost protection against N2C3. Non-protective mutants those involved in large adhesion protein (LapA) biosynthesis, flagellar synthesis and function, and O-antigen biosynthesis. We found that the inability of P. brassicacearum WCS365 mutants to grow in planta, and the inability to suppress pathogen growth, both partially contributed to loss of plant protection. We did not find a correlation between the extent of biofilm formed in vitro and pathogen protection in planta indicating that biofilm formation on abiotic surfaces may not fully predict pathogen exclusion in planta. Collectively, our work provides insights into mechanisms of biofilm formation and host colonization that shape the outcomes of host-microbe-pathogen interactions.","PeriodicalId":516554,"journal":{"name":"The ISME Journal","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144193349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}