Biology subjects

Bending, G. D.

Publications and source records attributed to Bending, G. D..

9 recordsLinked to original sources

bioRxiv2026

Advancing long-read metagenomic binning via single-copy-gene guided contrastive learning

Long-read sequencing advances metagenomics by producing highly contiguous assemblies and more complete metagenome-assembled genomes (MAGs). However, current long-read metagenomic binners fail to incorporate the rich information of long-read assemblies into representation learning and exhibit limited performance on complex datasets. Here, we show that a higher proportion of long-read assembled contigs contain single-copy genes (SCGs) and more SCGs per contig. Therefore, we developed SCGBinner, which leverages SCG-guided contrastive learning to exploit the advantage of long-read data for learning high-quality contig embeddings. SCGBinner consistently outperforms other binning methods across five simulated and seven real-world long-read datasets, especially on real-world high-diversity samples. For a deep agricultural soil metagenome, SCGBinner recovered 71% more high-quality MAGs and 38% more near-complete MAGs than the second-best method. Notably, SCGBinner uniquely recovered 449 novel high-quality species, which shed light on the predicted ecological roles of 65 uncharacterised families and 93 novel genera. Overall, SCGBinner could harness the potential of long-read sequencing to provide unprecedented insights into the microbial dark matter of complex microbial communities.

bioinformatics↗

bioRxiv2025

Rapid Assembly and Functional Differentiation of the Soil Surface Microbiome in Temperate Agricultural soil

The surface of dryland soils is typically covered by biological soil crusts (BSC) dominated by cyanobacteria, lichens or moss which contribute key ecosystem functions. However, while photosynthetic biota have been observed on the surface of temperate agricultural soils, understanding of the development, biodiversity and functional significance of these communities is extremely limited. We investigated the temporal development of the soil surface community following tillage and during subsequent growth of a wheat crop. Amplicon analysis showed that establishment of the soil surface microbiome was rapid over the winter period, with distinct communities of phototrophs, bacteria and protists detected 60 days after tillage. There was rapid succession with yellow-green algae (Xanthophyceae) dominating early stages of development, followed by Cyanobacteria and Charophytes and finally moss. Temporal dynamics of fungal and protist communities was influenced by eDNA deposition from plant pathogens inhabiting the crop canopy and wild animal parasites. For all groups, assembly processes in the surface soil became increasingly dominated by dispersal limitation over time while assembly of bulk soil communities became predominantly influenced by drift. Metagenome analysis showed that the soil surface had developed a distinct functional profile relative to bulk soil after 9 months, enriched in photosynthetic processes which were largely from eukaryotic algae rather than cyanobacteria. Additionally the 3-Hydroxypropionate bicycle and reductive TCA carbon fixation pathways were enriched in surface soil. The abundance of genes involved in heterotrophic carbon, nitrogen, phosphorus and sulphur cycling processes were also enriched in surface soil. This included reads of carbohydrate active enzymes, nitrification, denitrification and sulphate reduction genes, largely attributed to the enrichment of Actinobacteria, Bacteroidetes and Proteobacteria in the soil surface. Overall, we show overlap in dominant phototrophic taxa between temperate agricultural and BSC in arid soils, but with notable differences, including abundance of Xanthphycae and Charophytes. Furthermore, the functional signatures of the soil surface communities indicate that they may play an important role in the delivery of ecosystem functions in temperate agricultural systems.

microbiology↗

bioRxiv2024

Dynamics of Reactive Oxygen Species and Nitrogen Cycling in Soils as a Mechanism for Volatile Reactive Nitrogen Oxide Production

Heterotrophic bacteria and fungi are responsible for the decomposition of organic matter in soil. During this process, reactive oxygen species (ROS) can be produced directly and indirectly as extracellular byproducts of respiration. It is well known that nitrogen (N) cycle processes lead to the formation of volatile reactive nitrogen oxides (NOy), a group of climate-active gases that contribute to atmospheric chemistry and negatively impact human health. Primary microbial sources of NOy include ammonia- oxidising bacteria and denitrifying bacteria and fungi. Despite soil being a significant source of global NOy emissions, studies to date have primarily focused on N emissions from agricultural soils and there remains a large scope for investigating mechanisms of soil NOy production in a wider context in order to better constrain terrestrial and climate process models. Here, we propose a potential microbial mechanism involving ROS that could influence the production of NOy from soil. We utilised metagenomics and metatranscriptomics alongside continuous gas flux measurements and analysis of soil properties to evaluate the connection between microbial ROS and soil-sourced NOy. Our findings suggest that more NOy, particularly nitric oxide (NO), is produced in the presence of increased abundance of ammonia-oxidising and denitrifying taxa. NO can be lost to the environment or reacts with superoxide, an ROS produced via the enzymatic activity of soil organic matter (SOM) decomposers. This reaction produces peroxynitrite (ONOO-), which we have demonstrated to enhance nitrogen dioxide (NO2) emissions from soil. We have shown that the extent of NOy production through this pathway may be dependent on SOM composition, and the associated variability in carbon and nitrogen content.

microbiology↗

bioRxiv2024

Comparative genomic analysis of a metagenome-assembled genome reveals distinctive symbiotic traits in a Mucoromycotina fine root endophyte arbuscular mycorrhizal fungus

BackgroundRecent evidence shows that arbuscular mycorrhizal (AM) symbiosis is established by two distinct fungal groups, with the distinctive fine root endophyte morphotype formed by fungi from the sub-phylum Mucoromycotina rather than the sub-phylum Glomeromycotina. While Mucoromycotina AM fungi are globally distributed, there is currently no understanding of the genomic basis for their symbiosis or how this symbiosis compares to that of other mycorrhizal symbionts. ResultsWe used culture-independent metagenome sequencing to assemble and characterise the metagenome-assembled genome (MAG) of a putative fine root endophyte, which we show belonged to the family Planticonsortiaceae within the order Densosporales. The MAG shares key traits with Glomeromycotina fungi, which indicate obligate biotrophy, including the absence of fatty acid and thiamine biosynthesis pathways, limited enzymatic abilities to degrade plant cell walls, and a high abundance of calcium transporters. In contrast to Glomeromycotina fungi, it exhibits a higher capacity for degradation of microbial cell walls, a complete cellulose degradation pathway, low abundances of copper, nitrate and ammonium transporters, and a complete pathway for vitamin B6 biosynthesis. ConclusionThese differences highlight the potential for contrasting interactions between Mucoromycotina and Glomeromycotina AM fungi with their host plant and the environment which could support niche differentiation and complementary ecological functions.

microbiology↗

bioRxiv2022

Ecological and evolutionary patterns of virus-host interactions throughout a grassland soil depth profile

BackgroundSoil microbes play pivotal roles in global carbon cycling, however the fundamental interactions between microbes and their infecting viruses remain unclear. This is exacerbated with soil depth, where the patterns of viral dispersal, ecology, and evolution are markedly underexplored. To investigate viral communities across soil depth, we leveraged a publicly available metagenomic data set sampled from grassland soil in northern California. Results10,196 non-redundant vOTUs were recovered from soil sampled from 20 cm to 120 cm below the surface. Viral prevalence was high throughout the soil depth profile, with viruses infecting dominant soil phyla, including Actinomycetota. Contrary to leading hypotheses, lysogeny did not dominate in the soil viral communities. Viral diversity was investigated at both the population-level (i.e., macro diversity) and strain-level (i.e., micro diversity) to reveal diverse ecological and evolutionary patterns of virus-host interactions in surface and subsurface soil. ConclusionsBy investigating viral micro diversity in soil for the first time, we have uncovered patterns of antagonistic co-evolution across both surface and subsurface soils. Furthermore, we have provided evidence of soil viruses augmenting the remineralisation of soil carbon. While we continue to yield a more comprehensive understanding of soil viral ecology, our work appeals to future researchers to continue to investigate subsurface viral communities.

ecology↗

bioRxiv2022

Landscape scale ecology of Tetracladium spp. fungal root endophytes

BackgroundThe genus Tetracladium has been traditionally regarded as an Ingoldian fungus or aquatic hyphomycete - a group of phylogenetically diverse, polyphyletic fungi which grow on decaying leaves and plant litter in streams. Recent sequencing evidence has shown that Tetracladium spp. may also exist as root endophytes in terrestrial environments, and furthermore may have beneficial effects on the health and growth of their host. However, the diversity of Tetracladium spp. communities in terrestrial systems and the factors which shape their distribution are largely unknown. ResultsUsing a fungal community internal transcribed spacer amplicon dataset from 37 UK Brassica napus fields we found that soils contained diverse Tetracladium spp., most of which represent previously uncharacterised clades. The two most abundant OTUs, related to previously described aquatic T. furcatum and T. maxilliforme, were enriched in roots relative to bulk and rhizosphere soil. For both taxa, relative abundance in roots, but not rhizosphere or bulk soil was correlated with B. napus yield. The relative abundance of T. furcatum and T. maxilliforme OTUs across compartments showed very similar responses with respect to agricultural management practices and soil characteristics. The factors shaping the relative abundance of T. furcatum and T. maxilliforme OTUs in roots was assessed using linear regression and structural equation modelling. Relative abundance of Tetracladium maxilliforme and Tetracladium furcatum in roots increased with pH, concentrations of phosphorus, and increased rotation frequency of OSR. While it decreased with increased soil water content, concentrations of extractable phosphorus, chromium, and iron. ConclusionsThe genus Tetracladium as a root colonising endophyte is a diverse and wildly distributed part of the oilseed rape microbiome that positively correlates to crop yield. The main drivers of its community composition are crop management practices and soil nutrients.

microbiology↗

bioRxiv2022

Crop management shapes the diversity and activity of DNA and RNA viruses in the rhizosphere

BackgroundThe rhizosphere is a hotspot for microbial activity and contributes to ecosystem services including plant health and biogeochemical cycling. The activity of microbial viruses, and their influence on plant-microbe interactions in the rhizosphere, remains undetermined. Given the impact of viruses on the ecology and evolution of their host communities, determining how soil viruses influence microbiome dynamics is crucial to build a holistic understanding of rhizosphere functions. ResultsHere, we aimed to investigate the influence of crop management on the composition and activity of bulk soil, rhizosphere soil, and root viral communities. We combined viromics, metagenomics, and metatranscriptomics on soil samples collected from a 3-year crop rotation field trial of oilseed rape (Brassica napus L.). By recovering 1,059 dsDNA viral populations and 16,541 ssRNA bacteriophage populations, we expanded the number of underexplored Leviviricetes genomes by > 5 times. Through detection of viral activity in metatranscriptomes, we uncovered evidence of "Kill-the-Winner" dynamics, implicating soil bacteriophages in driving bacterial community succession. Moreover, we found the activity of viruses increased with proximity to crop roots and identified that soil viruses may influence plant-microbe interactions through the reprogramming of bacterial host metabolism. We have provided the first evidence of crop rotation-driven impacts on soil microbial communities extending to viruses. To this aim, we present the novel principal of "viral priming", which describes how the consecutive growth of the same crop species primes viral activity in the rhizosphere through local adaptation. ConclusionsOverall, we reveal unprecedented spatial and temporal diversity in viral community composition and activity across root, rhizosphere soil and bulk soil compartments. Our work demonstrates that the roles of soil viruses need greater consideration to exploit the rhizosphere microbiome for food security, food safety, and environmental sustainability.

ecology↗

bioRxiv2021

Tree phyllospheres are a habitat for diverse populations of CO-oxidising bacteria

BackgroundCarbon monoxide (CO) is a naturally occurring and ubiquitous trace gas in the atmosphere. As a product of combustion processes, it can reach concentrations in the mg/m3 range in urban areas, contributing to air pollution. Aerobic CO-degrading microorganisms have been identified previously and are thought to remove ~370 Tg of CO in soils and oceans per year. Based on the presence of genes encoding subunits of the enzyme carbon monoxide dehydrogenase in metagenomes, a large fraction of soil bacteria may have the potential for CO degradation. The activity and diversity of CO-degrading microorganisms in above ground habitats such as the phyllosphere has not been addressed, however, and their potential role in global CO cycling remains unknown. ResultsMonitoring of CO-degradation in leaf washes of two common British trees, Ilex aquifolium and Crataegus monogyna, demonstrated CO uptake in all samples investigated. Leaf washes of I. aquifolium had significantly higher CO oxidation rates than those of C. monogyna. A diverse range of bacterial taxa were identified as candidate CO-oxidising taxa based on high-throughput sequencing and multivariate statistical analysis of 16S rRNA amplicon data, as well as functional diversity analysis based on coxL, the gene encoding the large subunit of CO-dehydrogenase. Candidate CO-oxidising taxa included a range of Rhizobiales and Burkholderiales, of which the Burkholderiales OTUs were abundant colonisers of the phyllosphere at the time of sampling, as indicated by 16S rRNA gene sequencing. In addition, an estimated 12.4% of leaf OTUs in samples of this study contained coxL homologues, based on their predicted genomes. We also mined data of publicly available phyllosphere metagenomes for genes encoding subunits of CO-dehydrogenase which indicated that, on average, 25% of phyllosphere bacteria contained CO-dehydrogenase gene homologues. A CO-oxidising Phyllobacteriaceae strain was isolated from phyllosphere samples which contains genes encoding both CODH as well as a RuBisCO. ConclusionsThe phyllosphere, a vast microbial habitat, supports diverse and potentially abundant CO-oxidising bacteria. These findings identify tree phyllosphere bacteria as a potential sink for atmospheric CO and highlight the need for a more detailed assessment of phyllosphere microbial communities in the global cycle of CO.

microbiology↗

bioRxiv2018

Incomplete reprogramming of cell-specific epigenetic marks during asexual reproduction leads to heritable phenotypic variation in plants

Plants differ from animals in their capability to easily regenerate fertile adult individuals from terminally differentiated cells [1]. This unique developmental plasticity is commonly observed in nature where many species can reproduce asexually through the ectopic initiation of organogenic or embryogenic developmental programs [2, 3]. However, it is not currently known if this developmental reprogramming is coupled to a global epigenomic resetting, or what impact it has on the phenotype of the clonal progeny. Here we show that plants asexually propagated via induction of a zygotic developmental program do not fully reset cell-specific epigenetic imprints. These imprints are instead inherited even over multiple rounds of sexual reproduction, becoming fixed in hybrids and resulting in heritable molecular and physiological phenotypes that depend on the founder cell used. Our results demonstrate how novel phenotypic variation in plants can be unlocked through the incomplete reprogramming of cell-specific epigenetic marks during asexual propagation.

plant biology↗