Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants\uffe2\uff80\uff99 large volume of influence. Here, we present the development of 3D live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor made dual-illumination light-sheet system acquired scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3in size with as good as 5 \uffce\uffbcm resolution at a rate of up to one scan every 30 minutes. The system tracked the movement ofBacillus subtilispopulations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed towards the root cap, the point \uffe2\uff80\uff9cfirst contact\uffe2\uff80\uff9d, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions.Winemakers have long used copper as a conventional fungicide treatment on grapevine and only recently, the use of biocontrol agents depicted a promising alternative. Most of the studies that investigate the impact of fungicide treatments, focus on specific pathogenic microbes. In the present work instead, a field experiment conducted in South Africa shows the seasonal microbial change occurring on grapevine leaves, periodically treated with two different fungicide treatments: copper sulphate and Lactobacillus plantarum MW-1. In this work, NGS data were combined with strain-specific and community qPCRs to reveal the shift of the microbial communities throughout the growing season and highlight the impact of fungicides on the microbiota. Only the family of Lactobacillaceae systematically changed between treatments, while the bacterial community remained relatively stable over time. MW-1 was exclusively detected on biocontrol-sprayed leaves. Conversely, the fungal community was largely shaped by sampling time, underlining the succession of different dominant taxa over the months. Between treatments, only a few fungal taxa appeared to change significantly and the fungal load was also comparable. Monitoring the dynamics of the microbial community under different fungicide treatments may advise the best timing to apply treatments to the plants, toward the realization of more sustainable agricultural practices.
", "keywords": ["0301 basic medicine", "2. Zero hunger", "0303 health sciences", "Copper Sulfate", "Agriculture", "Article", "Fungicides", " Industrial", "3. Good health", "Plant Leaves", "South Africa", "03 medical and health sciences", "Vitis", "Seasons", "Lactobacillus plantarum", "Mycobiome"]}, "links": [{"href": "https://www.nature.com/articles/s41598-019-56741-z.pdf"}, {"href": "https://doi.org/10.1038/s41598-019-56741-z"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Scientific%20Reports", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1038/s41598-019-56741-z", "name": "item", "description": "10.1038/s41598-019-56741-z", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1038/s41598-019-56741-z"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-01-20T00:00:00Z"}}, {"id": "10.1038/s41598-023-49194-y", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:18:27Z", "type": "Journal Article", "created": "2023-12-13", "title": "Unraveling the genome of Bacillus velezensis MEP218, a strain producing fengycin homologs with broad antibacterial activity: comprehensive comparative genome analysis", "description": "AbstractBacillus sp. MEP218, a soil bacterium with high potential as a source of bioactive molecules, produces mostly C16\uffe2\uff80\uff93C17 fengycin and other cyclic lipopeptides (CLP) when growing under previously optimized culture conditions. This work addressed the elucidation of the genome sequence of MEP218 and its taxonomic classification. The genome comprises 3,944,892\uffc2\uffa0bp, with a total of 3474 coding sequences and a G\uffe2\uff80\uff89+\uffe2\uff80\uff89C content of 46.59%. Our phylogenetic analysis to determine the taxonomic position demonstrated that the assignment of the MEP218 strain to Bacillus velezensis species provides insights into its evolutionary context and potential functional attributes. The in silico genome analysis revealed eleven gene clusters involved in the synthesis of secondary metabolites, including non-ribosomal CLP (fengycins and surfactin), polyketides, terpenes, and bacteriocins. Furthermore, genes encoding phytase, involved in the release of phytic phosphate for plant and animal nutrition, or other enzymes such as cellulase, xylanase, and alpha 1\uffe2\uff80\uff934 glucanase were detected. In vitro antagonistic assays against Salmonella typhimurium, Acinetobacter baumanii, Escherichia coli, among others, demonstrated a broad spectrum of C16\uffe2\uff80\uff93C17 fengycin produced by MEP218. MEP218 genome sequence analysis expanded our understanding of the diversity and genetic relationships within the Bacillus genus and updated the Bacillus databases with its unique trait to produce antibacterial fengycins and its potential as a resource of biotechnologically useful enzymes.Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants\uffe2\uff80\uff99 large volume of influence. Here, we present the development of 3D live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor made dual-illumination light-sheet system acquired scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3in size with as good as 5 \uffce\uffbcm resolution at a rate of up to one scan every 30 minutes. The system tracked the movement ofBacillus subtilispopulations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed towards the root cap, the point \uffe2\uff80\uff9cfirst contact\uffe2\uff80\uff9d, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions.
", "keywords": ["0301 basic medicine", "570", "Microscopy", "Silicon", "0303 health sciences", "Temperature", "root-microbe interactions", "Equipment Design", "Biological Sciences", "Environment", "15. Life on land", "Plant Roots", "630", "Fluorescence", "Soil", "03 medical and health sciences", "Seedlings", "Calibration", "Rhizosphere", "Image Processing", " Computer-Assisted", "environmental imaging", "rhizosphere", "Soil Microbiology", "Bacillus subtilis", "Lactuca"]}, "links": [{"href": "https://eprints.whiterose.ac.uk/178939/18/e2109176118.full.pdf"}, {"href": "https://pnas.org/doi/pdf/10.1073/pnas.2109176118"}, {"href": "https://doi.org/10.1073/pnas.2109176118"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Proceedings%20of%20the%20National%20Academy%20of%20Sciences", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1073/pnas.2109176118", "name": "item", "description": "10.1073/pnas.2109176118", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1073/pnas.2109176118"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-02-13T00:00:00Z"}}, {"id": "10.1101/2023.06.28.546105", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:19:12Z", "type": "Journal Article", "created": "2023-06-29", "title": "Construction and Characterisation of a Structured, Tuneable, and Transparent 3D Culture Platform for Soil Bacteria", "description": "2.AbstractWe have developed a tuneable workflow for the study of soil microbes in an imitative 3D soil environment that is compatible with routine and advanced optical imaging, is chemically customisable, and is reliably refractive index matched based on the metabolic profile of the study organism. We demonstrate our transparent soil pipeline with two representative soil organisms,Bacillus subtilisandStreptomyces coelicolor, and visualise their colonisation behaviours using fluorescence microscopy and mesoscopy. This spatially structured, 3D approach to microbial culture has the potential to further study the behaviour of other difficult-to-culture bacteria in conditions matching their native environment and could be expanded to study microbial interactions, such as interaction, competition, and warfare.
3.Graphical AbstractA step-by-step method for creating a tailored 3D culture medium for study of soil microbes.
The complete workflow can be split into three parts: Growth and observation, metabolic profiling to provide a stable refractive index matching solution, and production of the 3D soil environment. The 3D culture scaffold was created by cryomilling Nafion\uffe2\uff84\uffa2 resin pellets and size filtration. Chemical processing altered the surface chemistry of Nafion\uffe2\uff84\uffa2 particles and facilitated nutrient binding by titration of a defined liquid culture medium. Metabolic profiling determined non-metabolisable sugars and provided an inert refractive index matching substrate, which was added to the final nutrient titration. Inoculation and growth of the test strain allowed for downstream assessment of colonisation behaviours and community dynamicsin situby, for example, optical microscopy.The increasingly widespread use of beneficial microbial inocula in agriculture gives rise to two primary needs: i) the assessment of the environmental risk, i.e. their impact on local soil microbiome and soil properties; ii) being able to track them and monitor their persistence and fate to both optimize their formulation and application method. In previous years, PCR-based methods have detected bacterial or fungal bioinoculant at the species or strain level. However, the selective detection, quantification, and monitoring of target microbial species in a complex ecosystem such as soil require that the tests possess high specificity and sensitivity.
Methods and resultsThe work proposes a quantitative real-time PCR detection method using TaqMan chemistry, showing high specificity and sensitivity for the Paenibacillus polymyxa K16 strain. The primer and probe sets were designed using the polymyxin gene cluster targeting pmxC and pmxE sequences. Validation tests showed that these assays allowed a discriminant and specific detection of P. polymyxa K16 in soil.
ConclusionThe TaqMan-assay developed could thus ensure the necessary level of discrimination required by commercial and regulatory purposes to detect and monitor the bioinoculant in soil.The rhizosphere hosts complex and abundant microbiomes whose structure and composition are now well described by metagenomic studies. However, the dynamic mechanisms that enable micro-organisms to establish along a growing plant root are poorly characterized. Here, we studied how a motile bacterium utilizes the microhabitats created by soil pore space to establish in the proximity of plant roots. We have established a model system consisting of Bacillus subtilis and lettuce seedlings co-inoculated in transparent soil microcosms. We carried out live imaging experiments and developed image analysis pipelines to quantify the abundance of the bacterium as a function of time and position in the pore space. Results showed that the establishment of the bacterium in the rhizosphere follows a precise sequence of events where small islands of mobile bacteria were first seen forming near the root tip within the first 12\uffe2\uff80\uff9324\uffe2\uff80\uff89h of inoculation. Biofilm was then seen forming on the root epidermis at distances of about 700\uffe2\uff80\uff931000\uffe2\uff80\uff89\uffc2\uffb5m from the tip. Bacteria accumulated predominantly in confined pore spaces within 200\uffe2\uff80\uff89\uffc2\uffb5m from the root or the surface of a particle. Using probabilistic models, we could map the complete sequence of events and propose a conceptual model of bacterial establishment in the pore space. This study therefore advances our understanding of the respective role of growth and mobility in the efficient colonization of bacteria in the rhizosphere.Bacteria of Lactobacillus sp. are very useful to humans. However, the biology and genomic diversity of their (bacterio)phage enemies remains understudied. Knowledge on Lactobacillus phage diversity should broaden to develop efficient phage control strategies. To this end, organic waste samples were screened for phages against two wine-related Lactobacillus plantarum strains. Isolates were shotgun sequenced and compared against the phage database and each other by phylogenetics and comparative genomics. The new isolates had only three distant relatives from the database, but displayed a high overall degree of genomic similarity amongst them. The latter allowed for the use of one isolate as a representative to conduct transmission electron microscopy and structural protein sequencing, and to study phage adsorption and growth kinetics. The microscopy and proteomics tests confirmed the observed diversity of the new isolates and supported their classification to the family Siphoviridae and the proposal of the new phage genus \uffe2\uff80\uff9cSilenusvirus\uffe2\uff80\uff9d.
", "keywords": ["0301 basic medicine", "0303 health sciences", "FRAMESHIFT", "Denmark", "BACTERIOPHAGES", "PROTEIN", "Wine", "Genome", " Viral", "Viral Plaque Assay", "SEQUENCE", "CLASSIFICATION", "Article", "12. Responsible consumption", "Microscopy", " Electron", "Waste Disposal Facilities", "03 medical and health sciences", "Bacteriolysis", "Species Specificity", "DNA", " Viral", "Bacteriophages", "Adsorption", "Phylogeny", "Lactobacillus plantarum"]}, "links": [{"href": "https://www.biorxiv.org/content/10.1101/728261v1.full.pdf"}, {"href": "https://doi.org/10.1101/728261"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Scientific%20Reports", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1101/728261", "name": "item", "description": "10.1101/728261", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1101/728261"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-08-07T00:00:00Z"}}, {"id": "10.1371/journal.pone.0200979", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:20:15Z", "type": "Journal Article", "created": "2019-04-11", "title": "Quantitative and qualitative evaluation of the impact of the G2 enhancer, bead sizes and lysing tubes on the bacterial community composition during DNA extraction from recalcitrant soil core samples based on community sequencing and qPCR", "description": "AbstractSoil DNA extraction encounters numerous challenges that can affect both yield and purity of the recovered DNA. Clay particles lead to reduced DNA extraction efficiency, and PCR inhibitors from the soil matrix can negatively affect downstream analyses when applying DNA sequencing. Further, these effects impede molecular analysis of bacterial community compositions in lower biomass samples, as often observed in deeper soil layers. Many studies avoid these complications by using indirect DNA extraction with prior separation of the cells from the matrix, but such methods introduce other biases that influence the resulting microbial community composition.
To address these issues, a direct DNA extraction method was applied in combination with the use of a commercial product, the G2 DNA/RNA Enhancer\uffc2\uffae, marketed as being capable of improving the amount of DNA recovered after the lysis step. The results showed that application of G2 increased DNA yields from the studied clayey soils from layers between 1.00 and 2.20 m below ground level.
Importantly, the use of G2 did not introduce bias, as it did not result in any significant differences in the biodiversity of the bacterial community measured in terms of alpha and beta diversity and taxonomical composition.
Finally, this study considered a set of customised lysing tubes for evaluating possible influences on the DNA yield. Tubes customization included different bead sizes and amounts, along with lysing tubes coming from two suppliers. Results showed that the lysing tubes with mixed beads allowed greater DNA recovery compared to the use of either 0.1 or 1.4 mm beads, irrespective of the tube supplier.
These outcomes may help to improve commercial products in DNA/RNA extraction kits, besides raising awareness about the optimal choice of additives, offering opportunities for acquiring a better understanding of topics such as vertical microbial characterisation and environmental DNA recovery in low biomass samples.
", "keywords": ["DNA", " Bacterial", "0301 basic medicine", "Science", "Microbial Consortia", "DIVERSITY", "SOFTWARE", "Real-Time Polymerase Chain Reaction", "BACILLUS-SUBTILIS", "BIOMASS", "03 medical and health sciences", "BIOAUGMENTATION", "DNA", " Bacterial/chemistry", "MICROBIAL COMMUNITIES", "Soil Microbiology", "2. Zero hunger", "0303 health sciences", "16S RIBOSOMAL-RNA", "Q", "R", "PROFILES", "ACIDS", "TRANSFORMATION", "6. Clean water", "Microbial Consortia/genetics", "Enhancer Elements", " Genetic", "13. Climate action", "Medicine", "Research Article"]}, "links": [{"href": "https://www.biorxiv.org/content/10.1101/365395v1.full.pdf"}, {"href": "https://doi.org/10.1371/journal.pone.0200979"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/PLOS%20ONE", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1371/journal.pone.0200979", "name": "item", "description": "10.1371/journal.pone.0200979", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1371/journal.pone.0200979"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2018-07-09T00:00:00Z"}}, {"id": "10.1534/g3.119.400716", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:20:22Z", "type": "Journal Article", "created": "2020-01-10", "title": "Whole Genome Sequencing and Comparative Genomics of Two Nematicidal Bacillus Strains Reveals a Wide Range of Possible Virulence Factors", "description": "AbstractBacillus firmus nematicidal bacterial strains are used to control plant parasitic nematode infestation of crops in agricultural production. Proteases are presumed to be the primary nematode virulence factors in nematicidal B. firmus degrading the nematode cuticle and other organs. We determined and compared the whole genome sequences of two nematicidal strains. Comparative genomics with a particular focus on possible virulence determinants revealed a wider range of possible virulence factors in a B. firmus isolate from a commercial bionematicide and a wild type Bacillus sp. isolate with nematicidal activity. The resulting 4.6 Mb B. firmus I-1582 and 5.3 Mb Bacillus sp. ZZV12-4809 genome assemblies contain respectively 18 and 19 homologs to nematode-virulent proteases, two nematode-virulent chitinase homologs in ZZV12-4809 and 28 and 36 secondary metabolite biosynthetic clusters, projected to encode antibiotics, small peptides, toxins and siderophores. The results of this study point to the genetic capability of B. firmus and related species for nematode virulence through a range of direct and indirect mechanisms.Lactobacilli are among the most common microorganisms found in kefir; a traditional fermented milk beverage produced locally in many locations around the world. Kefir has been associated with a wide range of purported health benefits; such as antimicrobial activity; cholesterol metabolism; immunomodulation; anti-oxidative effects; anti-diabetic effects; anti-allergenic effects; and tumor suppression. This review critically examines and assesses these claimed benefits and mechanisms with regard to particular Lactobacillus species and/or strains that have been derived from kefir; as well as detailing further potential avenues for experimentation.
", "keywords": ["kefiranofaciens", "0301 basic medicine", "2. Zero hunger", "0303 health sciences", "Probiotics", "Review", "Kefiri", "Probiotic", "6. Clean water", "plantarum", "3. Good health", "kefiri", "Lactobacillus", "03 medical and health sciences", "Kefir", "Species Specificity", "Kefiranofaciens", "Humans", "Plantarum", "probiotic"]}, "links": [{"href": "https://www.mdpi.com/2072-6643/11/6/1252/pdf"}, {"href": "https://doi.org/10.3390/nu11061252"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Nutrients", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/nu11061252", "name": "item", "description": "10.3390/nu11061252", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/nu11061252"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-06-01T00:00:00Z"}}, {"id": "10.3390/v11070611", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:22:04Z", "type": "Journal Article", "created": "2019-06-12", "title": "Expanding the Diversity of Myoviridae Phages Infecting Lactobacillus plantarum\u2014A Novel Lineage of Lactobacillus Phages Comprising Five New Members", "description": "Lactobacillus plantarum is a bacterium with promising applications to the food industry and agriculture and probiotic properties. So far, bacteriophages of this bacterium have been moderately addressed. We examined the diversity of five new L. plantarum phages via whole genome shotgun sequencing and in silico protein predictions. Moreover, we looked into their phylogeny and their potential genomic similarities to other complete phage genome records through extensive nucleotide and protein comparisons. These analyses revealed a high degree of similarity among the five phages, which extended to the vast majority of predicted virion-associated proteins. Based on these, we selected one of the phages as a representative and performed transmission electron microscopy and structural protein sequencing tests. Overall, the results suggested that the five phages belong to the family Myoviridae, they have a long genome of 137.973-141.344 bp, a G/C content of 36,3-36,6% that is quite distinct from their host’s, and, surprisingly, seven to 15 tRNAs. Only an average 41/174 of their predicted genes were assigned a function. The comparative analyses unraveled considerable genetic diversity for the five L. plantarum phages of this study. Hence, the new genus “Semelevirus” was proposed, which comprises exclusively the five phages. This novel lineage of Lactobacillus phages provides further insight into the genetic heterogeneity of phages infecting Lactobacillus sp.. The five new Lactobacillus phages have a potential value for the development of more robust starters through, for example, the selection of mutants insensitive to phage infections. The five phages could also form part of phage cocktails, which producers would apply in different stages of L. plantarum fermentations in order to create a range of organoleptic outputs.
", "keywords": ["0301 basic medicine", "Annotation", "comparative genomics", "Genome", " Viral", "Lactobacillus plantarum", "Microbiology", "Article", "Isolation", "diversity", "03 medical and health sciences", "Microscopy", " Electron", " Transmission", "DNA Packaging", "phage", "Bacteriophages", "Phylogeny", "Viral Structural Proteins", "2. Zero hunger", "Diversity", "Base Composition", "0303 health sciences", "Comparative genomics", "new genus", "Genomics", "Sequence Analysis", " DNA", "QR1-502", "virology", "Phylogenetics", "phylogenetics", "Lactobacillus", "annotation", "Myoviridae", "Phage", "New genus", "isolation", "Lactobacillus plantarum"]}, "links": [{"href": "http://www.mdpi.com/1999-4915/11/7/611/pdf"}, {"href": "https://www.mdpi.com/1999-4915/11/7/611/pdf"}, {"href": "https://doi.org/10.3390/v11070611"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Viruses", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/v11070611", "name": "item", "description": "10.3390/v11070611", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/v11070611"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-06-11T00:00:00Z"}}, {"id": "10.5281/zenodo.14626839", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:23:39Z", "type": "Dataset", "title": "Data set of soil microbial components in response to extreme spring events at variable temperatures", "description": "The soil microbial response to prolonged soil drought (20% field capacity FC), wetness (above FC) and moderate drought (common at 50% FC) was simulated in pots at two spring temperatures - 2\u00b0C and +2.5\u00b0C colder and warmer, respectively, compared to the average in the central-eastern Po Valley, Italy (decade 2014-2024).\u00a0 Two soils (a ploughed soil and an adjacent renatured soil) were subjected to two 60-day cycles (cold and warm spring) at three levels of soil water content. The climate simulation started after the wheat seedlings had reached the two-leaf stage in all pots. Soil samples were taken from the wheat rhizome at the end of each experiment. The response of microbial biomass was evaluated in terms of double-stranded DNA (dsDNA), total bacteria quantified as 16S gene copy number using Real Time PCR and total fungi quantified as 18S gene copy number using Digital PCR. Three major bacterial groups, Pseudomonas, Actinomycetes and Bacillus, were quantified by real-time PCR using specific primers of the 16S region (F968/Ps-r; F243/518r; BacF/518). Twenty-two enzyme activities were also quantified in soil samples. The data set contains a total of twenty-eight variables.", "keywords": ["climate change", "microbial biomass", "soil bacteria", "Pseudomonas", "actinomycetes", "estreme events", "soil fungi", "microrganisms", "Bacillus", "metabolic activity", "soil"], "contacts": [{"organization": "Manici, Luisa M.", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.14626839"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.14626839", "name": "item", "description": "10.5281/zenodo.14626839", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.14626839"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2026-01-10T00:00:00Z"}}, {"id": "2999294732", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:27:22Z", "type": "Journal Article", "created": "2020-01-10", "title": "Whole Genome Sequencing and Comparative Genomics of Two Nematicidal Bacillus Strains Reveals a Wide Range of Possible Virulence Factors", "description": "AbstractBacillus firmus nematicidal bacterial strains are used to control plant parasitic nematode infestation of crops in agricultural production. Proteases are presumed to be the primary nematode virulence factors in nematicidal B. firmus degrading the nematode cuticle and other organs. We determined and compared the whole genome sequences of two nematicidal strains. Comparative genomics with a particular focus on possible virulence determinants revealed a wider range of possible virulence factors in a B. firmus isolate from a commercial bionematicide and a wild type Bacillus sp. isolate with nematicidal activity. The resulting 4.6 Mb B. firmus I-1582 and 5.3 Mb Bacillus sp. ZZV12-4809 genome assemblies contain respectively 18 and 19 homologs to nematode-virulent proteases, two nematode-virulent chitinase homologs in ZZV12-4809 and 28 and 36 secondary metabolite biosynthetic clusters, projected to encode antibiotics, small peptides, toxins and siderophores. The results of this study point to the genetic capability of B. firmus and related species for nematode virulence through a range of direct and indirect mechanisms.Bacillus sp. MEP218, a soil bacterium with high potential as a source of bioactive molecules, produces mostly C16\uffe2\uff80\uff93C17 fengycin and other cyclic lipopeptides (CLP) when growing under previously optimized culture conditions. This work addressed the elucidation of the genome sequence of MEP218 and its taxonomic classification. The genome comprises 3,944,892\uffc2\uffa0bp, with a total of 3474 coding sequences and a G\uffe2\uff80\uff89+\uffe2\uff80\uff89C content of 46.59%. Our phylogenetic analysis to determine the taxonomic position demonstrated that the assignment of the MEP218 strain to Bacillus velezensis species provides insights into its evolutionary context and potential functional attributes. The in silico genome analysis revealed eleven gene clusters involved in the synthesis of secondary metabolites, including non-ribosomal CLP (fengycins and surfactin), polyketides, terpenes, and bacteriocins. Furthermore, genes encoding phytase, involved in the release of phytic phosphate for plant and animal nutrition, or other enzymes such as cellulase, xylanase, and alpha 1\uffe2\uff80\uff934 glucanase were detected. In vitro antagonistic assays against Salmonella typhimurium, Acinetobacter baumanii, Escherichia coli, among others, demonstrated a broad spectrum of C16\uffe2\uff80\uff93C17 fengycin produced by MEP218. MEP218 genome sequence analysis expanded our understanding of the diversity and genetic relationships within the Bacillus genus and updated the Bacillus databases with its unique trait to produce antibacterial fengycins and its potential as a resource of biotechnologically useful enzymes.Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants\uffe2\uff80\uff99 large volume of influence. Here, we present the development of 3D live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor made dual-illumination light-sheet system acquired scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3in size with as good as 5 \uffce\uffbcm resolution at a rate of up to one scan every 30 minutes. The system tracked the movement ofBacillus subtilispopulations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed towards the root cap, the point \uffe2\uff80\uff9cfirst contact\uffe2\uff80\uff9d, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions.The increasingly widespread use of beneficial microbial inocula in agriculture gives rise to two primary needs: i) the assessment of the environmental risk, i.e. their impact on local soil microbiome and soil properties; ii) being able to track them and monitor their persistence and fate to both optimize their formulation and application method. In previous years, PCR-based methods have detected bacterial or fungal bioinoculant at the species or strain level. However, the selective detection, quantification, and monitoring of target microbial species in a complex ecosystem such as soil require that the tests possess high specificity and sensitivity.
Methods and resultsThe work proposes a quantitative real-time PCR detection method using TaqMan chemistry, showing high specificity and sensitivity for the Paenibacillus polymyxa K16 strain. The primer and probe sets were designed using the polymyxin gene cluster targeting pmxC and pmxE sequences. Validation tests showed that these assays allowed a discriminant and specific detection of P. polymyxa K16 in soil.
ConclusionThe TaqMan-assay developed could thus ensure the necessary level of discrimination required by commercial and regulatory purposes to detect and monitor the bioinoculant in soil.Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants\uffe2\uff80\uff99 large volume of influence. Here, we present the development of 3D live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor made dual-illumination light-sheet system acquired scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3in size with as good as 5 \uffce\uffbcm resolution at a rate of up to one scan every 30 minutes. The system tracked the movement ofBacillus subtilispopulations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed towards the root cap, the point \uffe2\uff80\uff9cfirst contact\uffe2\uff80\uff9d, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions.We have developed a tuneable workflow for the study of soil microbes in an imitative 3D soil environment that is compatible with routine and advanced optical imaging, is chemically customisable, and is reliably refractive index matched based on the metabolic profile of the study organism. We demonstrate our transparent soil pipeline with two representative soil organisms,Bacillus subtilisandStreptomyces coelicolor, and visualise their colonisation behaviours using fluorescence microscopy and mesoscopy. This spatially structured, 3D approach to microbial culture has the potential to further study the behaviour of other difficult-to-culture bacteria in conditions matching their native environment and could be expanded to study microbial interactions, such as interaction, competition, and warfare.
3.Graphical AbstractA step-by-step method for creating a tailored 3D culture medium for study of soil microbes.
The complete workflow can be split into three parts: Growth and observation, metabolic profiling to provide a stable refractive index matching solution, and production of the 3D soil environment. The 3D culture scaffold was created by cryomilling Nafion\uffe2\uff84\uffa2 resin pellets and size filtration. Chemical processing altered the surface chemistry of Nafion\uffe2\uff84\uffa2 particles and facilitated nutrient binding by titration of a defined liquid culture medium. Metabolic profiling determined non-metabolisable sugars and provided an inert refractive index matching substrate, which was added to the final nutrient titration. Inoculation and growth of the test strain allowed for downstream assessment of colonisation behaviours and community dynamicsin situby, for example, optical microscopy.The rhizosphere hosts complex and abundant microbiomes whose structure and composition are now well described by metagenomic studies. However, the dynamic mechanisms that enable micro-organisms to establish along a growing plant root are poorly characterized. Here, we studied how a motile bacterium utilizes the microhabitats created by soil pore space to establish in the proximity of plant roots. We have established a model system consisting of Bacillus subtilis and lettuce seedlings co-inoculated in transparent soil microcosms. We carried out live imaging experiments and developed image analysis pipelines to quantify the abundance of the bacterium as a function of time and position in the pore space. Results showed that the establishment of the bacterium in the rhizosphere follows a precise sequence of events where small islands of mobile bacteria were first seen forming near the root tip within the first 12\uffe2\uff80\uff9324\uffe2\uff80\uff89h of inoculation. Biofilm was then seen forming on the root epidermis at distances of about 700\uffe2\uff80\uff931000\uffe2\uff80\uff89\uffc2\uffb5m from the tip. Bacteria accumulated predominantly in confined pore spaces within 200\uffe2\uff80\uff89\uffc2\uffb5m from the root or the surface of a particle. Using probabilistic models, we could map the complete sequence of events and propose a conceptual model of bacterial establishment in the pore space. This study therefore advances our understanding of the respective role of growth and mobility in the efficient colonization of bacteria in the rhizosphere.Bacillus firmus nematicidal bacterial strains are used to control plant parasitic nematode infestation of crops in agricultural production. Proteases are presumed to be the primary nematode virulence factors in nematicidal B. firmus degrading the nematode cuticle and other organs. We determined and compared the whole genome sequences of two nematicidal strains. Comparative genomics with a particular focus on possible virulence determinants revealed a wider range of possible virulence factors in a B. firmus isolate from a commercial bionematicide and a wild type Bacillus sp. isolate with nematicidal activity. The resulting 4.6 Mb B. firmus I-1582 and 5.3 Mb Bacillus sp. ZZV12-4809 genome assemblies contain respectively 18 and 19 homologs to nematode-virulent proteases, two nematode-virulent chitinase homologs in ZZV12-4809 and 28 and 36 secondary metabolite biosynthetic clusters, projected to encode antibiotics, small peptides, toxins and siderophores. The results of this study point to the genetic capability of B. firmus and related species for nematode virulence through a range of direct and indirect mechanisms.