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PubMed2026

Functional convergence of rTCA-related carbon-fixation potential and biochemical residue accumulation in seagrass sediments.

Seagrass meadows are globally significant blue carbon ecosystems, yet the microbial and biochemical mechanisms driving sediment organic carbon (SOC) accumulation remain poorly understood. To address this, we employed an integrated approach combining metagenomic sequencing, biochemical assays, and structural equation modeling to investigate carbon cycling in the seagrass and adjacent unvegetated sediments of Swan Lake, China. A total of 115,179 carbon fixation genes and 119,615 decomposition genes were identified, revealing distinct microbial community structures among the habitats. Seagrass sediments harbored more diverse carbon-fixing (CFMs) and decomposing microorganisms (CDMs), with 83 medium-to high-quality metagenome-assembled genomes (MAGs) recovered. While neutral community model analysis indicated that stochastic processes predominantly governed community assembly, functional analyses highlighted specific drivers of sequestration. The reductive tricarboxylic acid (rTCA) cycle emerged as the dominant carbon fixation pathway, with key genes (e.g., aclA, korA) showing strong positive correlations with SOC. Conversely, decomposition pathways for starch and lignin were negatively associated with SOC. Furthermore, seagrass sediments exhibited elevated concentrations of total amino sugars (TAS) and lignin phenols (TLP), which linked significantly to carbon fixation rather than decomposition. PLS-SEM revealed statistically significant associations among seagrass traits, environmental variables, microbial carbon-fixation potential, biochemical residue pools, and SOC, supporting a mechanistic pathway in which enhanced microbial functional potential drives the accumulation of recalcitrant biochemical residues, thereby facilitating long-term carbon retention in sediments. These findings emphasize the pivotal role of microbial anabolism and the accumulation of biosynthetic residues in sediment carbon storage, suggesting a functional convergence in seagrass-driven carbon sinks.

Metagenomics↗
PubMed2025

Coarse-grained model of serial dilution dynamics in synthetic human gut microbiome.

Many microbial communities in nature are complex, with hundreds of coexisting strains and the resources they consume. We currently lack the ability to assemble and manipulate such communities in a predictable manner in the lab. Here, we take a first step in this direction by introducing and studying a simplified consumer resource model of such complex communities in serial dilution experiments. The main assumption of our model is that during the growth phase of the cycle, strains share resources and produce metabolic byproducts in proportion to their average abundances and strain-specific consumption/production fluxes. We fit the model to describe serial dilution experiments in hCom2, a defined synthetic human gut microbiome with a steady-state diversity of 63 species growing on a rich media, using consumption and production fluxes inferred from metabolomics experiments. The model predicts serial dilution dynamics reasonably well, with a correlation coefficient between predicted and observed strain abundances as high as 0.8. We applied our model to: (i) calculate steady-state abundances of leave-one-out communities and use these results to infer the interaction network between strains; (ii) explore direct and indirect interactions between strains and resources by increasing concentrations of individual resources and monitoring changes in strain abundances; (iii) construct a resource supplementation protocol to maximally equalize steady-state strain abundances.

Gastrointestinal Microbiome↗
PubMed2026

Metabolome-driven rhizosphere microbiome assembly determining the health of medicinal herb (Angelica sinensis) against root rot.

BACKGROUND: The rhizosphere-associated microbiota plays a crucial role in plant responses to disease stress. Plant secondary metabolites are recognized as crucial mediators in the assembly of rhizosphere microbial communities, particularly by enhancing the colonization of beneficial microorganisms. Despite this recognized importance, a deeper understanding of how such metabolome-driven microbiome assembly specifically determines plant resistance against soil-borne diseases is still lacking. RESULTS: Here, we focused on the widely planted medicinal plant Angelica sinensis and demonstrated that root rot-diseased rhizosphere soils (DRS) exhibited a higher relative abundance of Fusarium and a lower relative abundance of Streptomyces compared to healthy rhizosphere soils (HRS). Shotgun metagenomic sequencing revealed that metabolism-associated genes, particularly those related to steroid degradation, are significantly enriched in HRS samples. Subsequent genome and functional gene analysis of Streptomyces revealed that the steroid degradation-related genes are associated with rhizosphere colonization in hosts. Rhizosphere Streptomyces S15 directly antagonized Fusarium and enhanced the root resistance of A. sinensis. Comparative metabolomics showed that A. sinensis plants from HRS secreted more lipid and lipid-like molecules than those from DRS, especially sterol lipids and long-chain fatty acids, which promoted the growth of Streptomyces S15 isolates. Transcriptome analysis validated that the lipid hormones are essential for sporulation, biofilm formation, and streptomycin biosynthesis of S15 strain. Finally, exogenous application of synbiotics (lipid prebiotics and S15) to A. sinensis resulted in the enrichment of S15-homologous Streptomyces amplicon sequence variant (ASV), further establishing beneficial bacterial communities in Fusarium-stressed rhizospheres. CONCLUSIONS: Our study proposes that A. sinensis recruits steroid-metabolizing Streptomyces species by exuding key lipid compounds (i.e., methyl jasmonate and brassinolide) to combat Fusarium root rot. This study provides novel insights into using functional synbiotics as a promising strategy for manipulating plant-microbiome interactions to promote sustainable agriculture. Video Abstract.

Rhizosphere↗
PubMed2026

Heavy-metal stress shapes habitat-specific microbial survival strategies in estuarine environments.

Estuarine ecosystems face increasing heavy metal pollution from rapid urbanization and industrialization, yet the microbial adaptive strategies to multiple metal stressors across different habitats remain poorly understood. This study investigated the diversity and composition of bacterial and fungal communities across free-living (FL), particle-attached (PA), and sediment (SE) fractions from three estuaries with varying heavy metal contamination, and further investigated functional adaptations of bacterial communities. High-throughput amplicon sequencing revealed habitat-specific communities, with SE hosting the highest alpha diversity and enrichment of metal-resistant genera such as Woeseia and Sva1033. Environmental filtering, particularly by Zn, was the dominant driver shaping bacterial assemblages across all habitats, whereas fungal communities displayed greater stochastic assembly patterns. Analysis of 44 high-quality bacterial metagenome-assembled genomes (MAGs) revealed diverse metal resistance genes (cusA, znuB, and zntA), along with enriched metabolic pathways for carbon, nitrogen, and sulfur cycling. Notably, both active efflux/oxidative stress defense and indirect immobilization mechanisms were observed across all habitats, but their relative importance differed: FL and PA communities exhibited a greater reliance on active metal efflux (czcAB) and oxidative stress defense (trxAB) to maintain intracellular homeostasis, whereas SE communities displayed a stronger genomic potential for sulfate reduction (dsrAB) that may contribute to metal immobilization through sulfide precipitation. This metabolic partitioning highlights the complementary roles of different habitats in mediating metal toxicity and biogeochemical cycling, providing new insights into microbial resilience in polluted estuaries and underscoring the urgency of addressing heavy-metal contamination in these critical ecosystems.

Estuaries↗
PubMed2026

Dynamics of soil fungal communities restored with biochar from a quarry site.

Quarrying activities have intensified due to population expansion, leading to landscape degradation and ecological destruction. Quarry restoration is usually mandatory in Hong Kong, China. Although biochar is used for sustainable soil amendment, its effectiveness in restoring quarry soil with poor properties has rarely been investigated. A 24-month field study was conducted to evaluate the ecological feasibility of restoring a quarry site by using native species (that is, Castanopsis fissa and Cyclobalanopsis edithiae) and biochar amendment. The results revealed that after 24 months, the application of biochar increased the organic carbon, phosphorus and potassium of the vegetated soil by at least 120 %, 31 % and 12 %, respectively, due to higher cation exchange capacity and better plant growth. The relative abundance of Ascomycota and Basidiomycota increased by 24 % and 47 % with biochar application when C. fissa was planted, which was likely associated with the improved nutrient cycling and soil fertility. Even though adding biochar to bare soil was found to increase the complexity of fungal co-occurrence networks, biochar application only increased fungal diversity in vegetated quarry soil but usually reduced its fungal richness. Moreover, fungal co-occurrence networks in vegetated soil became less complex, suggesting that biochar potentially helped plants to assemble specific, beneficial fungal communities. This effect is most pronounced in the soil planted with C. edithiae, where the structure of fungal communities after 24 months was significantly different from that at other restoration times. This study identifies key fungal phyla enhanced by biochar in quarry soil and provides an effective strategy for facilitating the restoration and management of degraded lands, especially quarry sites.

Charcoal↗
PubMed2026

Two worlds beneath: Distinct microbial strategies of the rock-attached and planktonic subsurface biosphere.

BACKGROUND: Microorganisms in groundwater ecosystems exist either as planktonic cells or as attached communities on aquifer rock surfaces. Attached cells outnumber planktonic ones by at least three orders of magnitude, suggesting a critical role in aquifer ecosystem function. However, particularly in consolidated carbonate aquifers, where research has predominantly focused on planktonic microbes, the metabolic potential and ecological roles of attached communities remain poorly understood. RESULTS: To investigate the differences between attached and planktonic communities, we sampled the attached microbiome from passive samplers filled with crushed carbonate rock exposed to oxic and anoxic groundwater in the Hainich Critical Zone Exploratory and compared it to a previously published, extensive dataset of planktonic communities from the same aquifer ecosystem. Microbial lifestyle (attached vs. planktonic) explained more variance in community composition than redox conditions, prompting us to further investigate its role in shaping functional and activity profiles. Metagenomic analysis revealed a striking taxonomic and functional segregation: the 605 metagenome-assembled genomes (MAGs) from attached communities were dominated by Proteobacteria (358 MAGs) and were enriched in genes for biofilm formation, chemolithoautotrophy, and redox cycling (e.g., iron and sulfur metabolism). In contrast, the 891 MAGs from planktonic communities were dominated by Cand. Patescibacteria (464 MAGs) and Nitrospirota (60 MAGs) and showed lower functional versatility. Only a few genera were shared, and even closely related MAGs (> 90% average nucleotide identity) differed in assembly size and metabolic traits, demonstrating lifestyle-specific functional adaptation. Analysis of active replication indicated that the active fraction of the attached community was primarily represented by the most abundant MAGs. Planktonic communities featured a higher fraction of active MAGs compared to attached communities, but overall with lower relative abundances. CONCLUSIONS: The high abundance, metabolic specialization, and carbon fixation potential of attached microbes suggest that they are key drivers of subsurface biogeochemical processes. Carbonate aquifers may act as much larger inorganic carbon sinks than previously estimated based on CO2 fixation rates of the planktonic communities alone. Our findings underscore the need to incorporate attached microbial communities into models of subsurface ecosystem function. Video Abstract.

Plankton↗
PubMed2026

Characteristics and assembly mechanisms of tobacco-associated bacteria in typical tobacco-planting regions across China.

INTRODUCTION: Plant-associated microbiota critically modulates host growth and environmental adaptation, yet assembly mechanisms, niche differentiation, and ecological strategies of bacterial communities inhabiting tobacco microhabitats remain poorly elucidated across geographical gradients. METHODS: Here, we systematically characterized bacterial microbiome assembly across five tobacco-associated niches (bulk soil, rhizosphere soil, root, stem, and leaf) from seven typical tobacco-planting regions using 16S rRNA amplicon sequencing, genome annotation, and niche breadth analysis. The independent and interactive effects of geographical location and host compartment on community structure, and further compared genomic traits, functional profiles, and life-history strategies between specialist and generalist bacterial populations were quantified. RESULTS: The results revealed a deterministic soil-plant continuum stratification of bacterial communities and diversity, with progressively simplified communities and decreasing alpha diversity from bulk soil to above-ground tissues, accompanied by progressive dominance of Proteobacteria. Geographical factors predominantly structured soil microbial communities via divergent edaphic properties, while host filtering acted as a universal dominant driver shaping endophytic microbiome assembly. Niche differentiation analysis demonstrated that niche-specialized bacterial ASVs overwhelmingly dominated all microhabitats and geographical sites, whereas generalist taxa only constituted auxiliary populations. Although specialist and generalist microbes exhibited highly conserved core genomic architectures and overall functional repertoires, they displayed distinct niche-specific functional divergence in metabolic pathways, stress resistance, and secondary metabolism across host compartments. Life-history strategy analysis further revealed that Y-strategist represented the core adaptive bacterial population, especially enriched in above-ground tobacco tissues. DISCUSSION: Our study establishes a hierarchical dual-filtering assembly model for tobacco microbiota, clarifies the ecological differentiation and functional adaptation of specialist and generalist bacteria, and provides fundamental insights into the assembly rules and adaptive mechanisms of crop-associated microbiomes for future microbial resource utilization and agricultural microbiome regulation.

biogeography↗
PubMed2025

Diploid genome assembly of human fibroblast cell lines enables clone specific variant calling, improved read mapping and accurate phasing.

Human cell lines are fundamental tools in biomedical research and are widely used in disease modeling, drug development, and many other domains. Here, we present chromosome-level, phased diploid genome assemblies of two popular human cell lines: the BJ foreskin fibroblast line and the IMR-90 fetal lung fibroblast line. Our high-quality assemblies, generated using long-read and Hi-C sequencing data, reveal substantial structural variation, including more than 50,000 insertions, deletions, duplications, and inversions compared to the recent T2T-CHM13v2.0 reference. Our assemblies provide detailed maps of genetic variation, enabling more accurate variant calling and the ability to phase reads when using newly generated or historical sequencing data on these cell lines or their derivatives. All assemblies and associated data have been made available as a resource for the research community. We envision that diploid genome assembly will become a cornerstone approach for personalized medicine in the near future.

Journal Article↗
PubMed2026

Perseus: Lineage-Aware Refinement of Kraken2 Taxonomic Classification for Long Read Metagenomes.

MOTIVATION: Long-read metagenomic sequencing improves assembly contiguity and enables genome-resolved analysis of complex microbial communities, but accurate taxonomic classification of long reads and assembled contigs remains challenging. Highly scalable k-mer-based classifiers such as Kraken2 frequently over-assign fine-rank taxonomic labels when applied to long-read data, producing high false positive classification rates driven by sparse or localized k-mer matches, particularly in microbiomes with extensive taxonomic novelty. RESULTS: We present Perseus, a lineage-aware confidence estimation framework for taxonomic classification that models the spatial distribution and hierarchical consistency of k-mer evidence along sequences. This formulation reframes taxonomic classification as a hierarchical confidence estimation problem rather than a single-rank prediction task. Perseus refines k-mer-level taxonomic signals from Kraken2 using a multi-headed convolutional neural network that estimates calibrated confidence scores for taxonomic correctness at each canonical rank. Using these estimates, Perseus confirms assignments, backs off to higher taxonomic ranks, or abstains when evidence is insufficient, prioritizing correctness and lineage consistency over overly specific assignments. Across simulations of taxonomic novelty and real-world metagenomic datasets, Perseus consistently and substantially reduces the false assignment rate while improving precision and lineage-consistent accuracy. These improvements are most pronounced for long reads and assembled contigs, where spatial context enables reliable discrimination between consistent taxonomic signal and spurious matches. AVAILABILITY AND IMPLEMENTATION: Perseus integrates with existing Kraken2 workflows and is available at https://github.com/matnguyen/perseus.

Journal Article↗
PubMed2025

Synergic impact mechanisms of cover crop residue on Cd and As availability and native organic carbon mineralization in Cd and As co-contaminated paddy soil.

The synergic impacts of cover crop residue on heavy metal and metalloid availability and soil organic carbon (SOC) mineralization in contaminated paddy soil and the underlying microbial mechanism remain unclear. This study investigated the availability of cadmium (Cd) and arsenic (As) and mineralization of native SOC in paddy soil treated with 0, 0.4 %, 0.8 % and 1.2 % of δ13C-labeled cover crop residue (Astragalus sinicus L.) via 90-day incubation experiments, the related functional genes and functional microbial communities were analyzed using metagenomic binning assembly. Cover crop residue with addition rate from 0.4 % to 1.2 % significantly decreased available Cd by 56 %-85 % but increased available As by 39 %-66 % compared to the control treatment. Cover crop residue resulted in a positive priming effect on native SOC mineralization but benefited SOC sequestration. Cover crop residue increased the abundance of genes encoding iron reductase (mtrABC, pilA, omcB), sulfate reductase (sir, fpr), As(V) reductase (ArsC), organic carbon hydrolases, methanogenesis, and methylotrophy. Genomes associated with Chloroflexota and Bacteroidota encoded all these key pathways, and their abundance increased with cover crop residue application. Cover crop residue decreased soil Eh, dissolved crystalline iron oxides, enriched specific microorganisms, including Chloroflexota and Bacteroidota, and then synergistically promoted the decrease in Cd availability and the increase in As availability and native SOC mineralization in the examined paddy soil. These findings provided practical and feasible guidance for achieving both safe production and carbon sequestration in contaminated paddy fields, highlighting the requirement to cautious utilization of cover crop residue in As-contaminated paddy fileds.

Soil Pollutants↗
PubMed2026

Widespread horizontal transfer and strong selection enhance microbial adaptation in Antarctic soils.

Terrestrial Antarctica harbors compositionally diverse and functionally distinct microbial life. Yet the eco-evolutionary processes underlying adaptation to Antarctica's polyextreme conditions remain largely unknown. Here, we address how horizontal gene transfer (HGT) and de novo mutations influence microbial adaptation in 16 Antarctic soils using combined short- and long-read datasets. Phylogenetic reconciliation and mobile genetic element analysis of 676 metagenome-assembled genomes show frequent HGT across communities. While transferred genes span diverse functional categories, those involved in energy metabolism are exchanged at higher frequency. Genes for aerotrophy, i.e. the consumption of atmospheric trace gases to provide energy, carbon, and hydration, are among the most frequently disseminated. Approximately a quarter of carbon monoxide dehydrogenases and [NiFe]-hydrogenases are predicted to be horizontally acquired and are often associated with mobile genetic elements. Analysis of polymorphisms suggests widespread purifying selection, particularly for aerotrophy genes, providing further evidence that aerotrophy is critical for microbial survival in Antarctica. Genetic variation in hydrogenases is tightly associated with predicted protein structures, with intense selection acting on critical sites preserving stability and function. Together, these findings show that previously unrecognized eco-evolutionary dynamics shape the composition and function of Antarctic microbial communities, and confirm aerotrophy is a strongly selected and horizontally disseminated trait.

Antarctic Regions↗
PubMed2026

Persistent antimicrobial resistance during soil remediation driven by residual heavy metal co-selection.

Remediation of heavy metal-contaminated soil is a global priority, particularly as reclaimed land increasingly intersects with urban development and human exposure. However, the ecological consequences of soil remediation, especially its impact on antimicrobial resistance (AMR) as a global health threat, have remained poorly understood. Here, we combined single-cell Raman-D₂O probing with genome-resolved metagenomics to monitor the dynamics of phenotypic and genotypic resistance to metals and antibiotics during a 120-day remediation of soils with three contamination levels from a lead-zinc smelting site. Although chemical remediation substantially reduced bioavailable metals (by 42%-65%), AMR was not diminished. Instead, both phenotypic activity and gene abundance of metal- and antibiotic-resistant microorganisms increased, resulting in a two- to three-fold increase in AMR-associated health risks. Among 76 metagenome assembled genomes (MAGs) from phenotypic resistance communities, all Cd resistance-associated MAGs harbored multidrug resistance genes, half of which were colocalized with metal resistance determinants, and their prevalence continued to rise with remediation. These findings reveal that although remediation alleviates acute metal toxicity, residual low-concentration bioavailable metals sustain evolutionary selection for resistance, highlighting a disconnect between chemical recovery and biological safety. Moreover, the improved soil nutrient and physiochemical properties of remediated soils further promoted the proliferation of antibiotic-resistant bacteria. This study offers new ecological insights into the unintended consequences of anthropogenic interventions, underscoring the need to integrate biological safety into soil health and safety assessments.

Soil Microbiology↗
PubMed2026

Microbial membrane transporters reveal trace metal niche adaptation in distinct water masses of the Southern Ocean.

BACKGROUND: Trace metals are co-factors for enzymes that are essential for microbial metabolism and the cycling of major elements. Membrane transporters allow microbes to sense and react to trace elements in the environment and to balance their uptake and export for the regulation of intracellular metal homeostasis. The acquisition and efflux of trace metals could lead to reciprocal feedbacks between microbes and the surrounding environment. Whether these processes vary among trace metals and across habitats is presently not known. We used membrane transporters into and out of the cell as indicators for the uptake and efflux of trace metals and provide a detailed picture of the distribution of the respective genes in distinct provinces in surface waters and in subsurface water masses across a transect in the Southern Indian Ocean. RESULTS: We observed marked spatial and vertical patterns in normalized gene abundances of transporters of iron (Fe), manganese (Mn), nickel (Ni) and copper (Cu). Changes in gene abundances were specific to the type of transporter and trace metal, and pronounced differences between surface and specific water masses emerged. We found an enrichment in genes related to efflux and homeostasis of Fe, Ni and Cu in two water masses of the deep ocean that are North Atlantic Deep Water (NADW) and Lower Circumpolar Deep Water (LCDW). This pattern was observed on the community level and for metagenome-assembled genomes (MAGs) affiliated with Alteromonadaceae and Burkholderiaceae that were abundant in these two water masses. CONCLUSIONS: The enrichment in trace metal efflux and resistance genes points to microbially mediated processes, exerted by homeostasis, with potential influence on the trace metal speciation and distribution in specific water masses in the deep ocean. The gene repertoire and distinct distribution pattern of the taxa identified as potential key players could reflect an adaptation to these old water masses with trace metals acting as selective driver. Video Abstract.

Membrane Transport Proteins↗
PubMed2026

VirBinn improves viral genome binning from metagenomic Hi-C through graph diffusion.

MOTIVATION: Metagenomic Hi-C provides in situ proximity signals that can improve genome binning and enable virus-host-association analysis. However, viral genome recovery remains difficult because virus-virus Hi-C contact matrices are extremely sparse. Viral genomes are small, often low-abundance, and frequently assemble into short contigs, leaving many true within-genome links unobserved and causing viral bins to fragment. RESULTS: We present VirBinn, a graph-diffusion framework for viral binning from metagenomic Hi-C. VirBinn enhances virus-virus connectivity through two complementary mechanisms: random-walk-with-restart enhancement on the sparse virus-virus contact graph and host-guided diffusion that propagates viral seeds through the host network to infer indirect virus-virus associations. The enhanced views are integrated and clustered using Leiden community detection to produce viral metagenome-assembled genomes (vMAGs). On dataset-specific simulation benchmarks with ground truth, VirBinn consistently recovers more high-quality vMAGs than Hi-C-based and shotgun-based baselines and substantially increases the number of near-complete genomes. On four real metagenomic Hi-C datasets spanning human gut, pig gut, sheep gut (long-read assembly), and wastewater, VirBinn yields more high-completeness vMAGs under CheckV and produces bins with strong within-cluster contact support. Finally, host linkage analysis using reconstructed host MAGs reveals habitat-specific host-association patterns and plausible host taxonomic profiles. AVAILABILITY AND IMPLEMENTATION: VirBinn is available at https://github.com/dyxstat/VirBinn. The scripts to reproduce the results and figures in this article are available at https://github.com/dyxstat/Reproduce_VirBinn.

Genome, Viral↗
PubMed2025

Depth-dependent multi-kingdom microbial interactions and biogeochemical cycling genes in eutrophic shallow lake sediments.

Microorganisms are pivotal to lake ecosystem biogeochemical cycles, yet existing research often focuses on single microbial kingdoms or surface sediments, neglecting multi-kingdom interactions and depth-resolved dynamics. To address these gaps, we used metagenomic sequencing to characterize microbial communities and their functional associations across overlying water and 0-45 cm sediments in four shallow lakes of the middle Yangtze River basin, China. Despite increasing bacterial and fungal diversity with depth, the 0-9 cm surface sediments exhibited the strongest multi-kingdom network connectivity and the greatest microbial stability. Functional genes exhibited clear depth-dependent patterns: nitrogen cycling genes, including those involved in dissimilatory nitrate reduction to ammonium, were most enriched in the upper 0-9 cm of sediment; methane cycling genes were positively correlated with depth; phosphorus cycling genes and some sulfur cycling genes, such as assimilatory sulphate reduction, declined with depth. Sediment microbial assembly was dominated by deterministic processes, in which the vertical distribution of functional genes was primarily dictated by heavy metals and conventional environmental indicators. These findings highlight depth-specific multi-kingdom microbial interactions and their associations with biogeochemical cycling, advancing lacustrine microbial ecology understanding and providing references for lake conservation under environmental change.

Lakes↗
PubMed2025

A method for authenticating the fidelity of Cryptococcus neoformans knockout collections.

Gene knockout (KO) strain collections are important tools for discovery in microbiology. Cryptococcus neoformans, a human fungal pathogen, has an available genome-wide gene deletion collection that is widely used by the research community. We uncovered mix-ups in the assembly of the commercially available C. neoformans deletion collection of ~4,700 unique strains acquired by our laboratory. Evidence supporting a mix-up includes RNAseq analysis that identified transcripts for the gene listed as the KO. The mystery was soon solved as this same KO strain lacked RNA transcripts for a different KO strain gene found in the same plate position in an earlier partial KO collection, suggesting a plate swap between two KO collections. Therefore, we developed a quick PCR assay to distinguish the two KO collections based on the size differences between their nourseothricin (NAT)-resistance cassettes, confirmed by genome sequencing. Here, we report that nine of the first 15 plates of the 42-plate our KN99ɑ KO collection had been replaced with the corresponding plates from an earlier partial KO collection. We provide additional evidence that the remaining plates are correct, and the simple authentication method presented here serves as a quick check to identify similar mix-ups in the KO collections.IMPORTANCEGene KO strain collections are important tools for discovery in microbiology. The human fungal pathogen Cryptococcus neoformans has an available genome-wide deletion collection that is widely used by the research community. Here, we report that our KN99ɑ collection is comprised of mixed plates from two independent KO libraries and present a simple authentication method that other investigators can use to distinguish the identities of these KO collections. Above all, this article serves as a reminder to users of the 2015 KO library collection to screen the plates before undertaking large phenotyping experiments.

Cryptococcus neoformans↗
PubMed2026

Synthetic community derived from the root core microbes of a desert shrub Caragana korshinskii enhances wheat drought tolerance.

BACKGROUND: Drought, intensified by climate change, poses a mounting threat to global food security by severely constraining crop productivity. While microbial inoculants offer promise for drought tolerance, their poor adaptability remains insufficient for extremely water-deficient environments. Desert plants host unique drought-adapted microbiomes that remain largely unexplored for agricultural applications. RESULTS: Here, we investigated the microbial community of the desert shrub Caragana korshinskii and identified a core set of drought-responsive strains. A synthetic microbial community (SynCom) derived from these strains significantly improved wheat growth under drought stress. Metagenomic analyses revealed that microbial functions related to biofilm formation, quorum sensing, and carbon metabolism were enriched, with Pseudomonas identified as a key functional taxon. Guided by inter-strain interactions in biofilm assembly, we streamlined the consortium into a five-member synthetic community, where quorum-sensing signals promoted community-wide biofilm formation. Community biofilm production improved strain colonization and conferred greater drought tolerance compared to monocultures. In plants, mechanistic investigations indicated that the simplified SynCom inoculation universally upregulated MAPK and jasmonic acid signaling pathways. Furthermore, carbohydrate metabolic pathways such as starch and sucrose metabolism were specifically activated, suggesting a multi-level mechanism underlying SynCom-mediated drought tolerance. CONCLUSIONS: These findings demonstrate that SynCom constructed on the endophytic flora of desert plants can significantly enhance crop drought tolerance. Our work highlights the pivotal role of community biofilm synthesis in facilitating root colonization and activating a multidimensional drought tolerance network in plants. This study not only gives an ecological perspective on desert microbiome adaptations but also offers a strategic framework for developing effective microbial inoculants for arid-region agriculture. Video Abstract.

Caragana↗