The Wheat Microbiome Under Four Management Strategies, and Potential for Endophytes in Disease Protection

Manipulating plant-associated microbes to reduce disease or improve crop yields requires a thorough understanding of interactions within the phytobiome. Plants were sampled from a wheat/maize/soybean crop rotation site that implements four different crop management strategies. We analyzed the fungal and bacterial communities of leaves, stems, and roots of wheat throughout the growing season using 16S and fungal internal transcribed spacer 2 rRNA gene amplicon sequencing. The most prevalent operational taxonomic units (OTUs) were shared across all samples, although levels of the low-abundance OTUs varied. Endophytes were isolated from plants, and tested for antagonistic activity toward the wheat pathogen Fusarium graminearum. Antagonistic strains were assessed for plant protective activity in seedling assays. Our results suggest that microbial communities were strongly affected by plant organ and plant age, and may be influenced by management strategy.

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Termites Are Associated with External Species-Specific Bacterial Communities

Applied and Environmental Microbiology ◽

10.1128/aem.02042-20 ◽

2020 ◽

Vol 87 (2) ◽

Author(s):

Patrik Soukup ◽

Tomáš Větrovský ◽

Petr Stiblik ◽

Kateřina Votýpková ◽

Amrita Chakraborty ◽

...

Keyword(s):

Bacterial Communities ◽

Amplicon Sequencing ◽

Rrna Gene ◽

Negative Effects ◽

Termite Species ◽

Positive Effects ◽

Operational Taxonomic Units ◽

Wide Range ◽

Species Specific ◽

And Control

ABSTRACT All termites have established a wide range of associations with symbiotic microbes in their guts. Some termite species are also associated with microbes that grow in their nests, but the prevalence of these associations remains largely unknown. Here, we studied the bacterial communities associated with the termites and galleries of three wood-feeding termite species by using 16S rRNA gene amplicon sequencing. We found that the compositions of bacterial communities among termite bodies, termite galleries, and control wood fragments devoid of termite activities differ in a species-specific manner. Termite galleries were enriched in bacterial operational taxonomic units (OTUs) belonging to Rhizobiales and Actinobacteria, which were often shared by several termite species. The abundance of several bacterial OTUs, such as Bacillus, Clostridium, Corynebacterium, and Staphylococcus, was reduced in termite galleries. Our results demonstrate that both termite guts and termite galleries harbor unique bacterial communities. IMPORTANCE As is the case for all ecosystem engineers, termites impact their habitat by their activities, potentially affecting bacterial communities. Here, we studied three wood-feeding termite species and found that they influence the composition of the bacterial communities in their surrounding environment. Termite activities have positive effects on Rhizobiales and Actinobacteria abundance and negative effects on the abundance of several ubiquitous genera, such as Bacillus, Clostridium, Corynebacterium, and Staphylococcus. Our results demonstrate that termite galleries harbor unique bacterial communities.

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Handling of spurious sequences affects the outcome of high-throughput 16S rRNA gene amplicon profiling

ISME Communications ◽

10.1038/s43705-021-00033-z ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Sandra Reitmeier ◽

Thomas C. A. Hitch ◽

Nicole Treichel ◽

Nikolaos Fikas ◽

Bela Hausmann ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Amplicon Sequencing ◽

Rrna Gene ◽

Diversity Analysis ◽

Careful Attention ◽

Operational Taxonomic Units ◽

Basic Concepts ◽

Gnotobiotic Mice ◽

Mock Communities

Abstract16S rRNA gene amplicon sequencing is a popular approach for studying microbiomes. However, some basic concepts have still not been investigated comprehensively. We studied the occurrence of spurious sequences using defined microbial communities based on data either from the literature or generated in three sequencing facilities and analyzed via both operational taxonomic units (OTUs) and amplicon sequence variants (ASVs) approaches. OTU clustering and singleton removal, a commonly used approach, delivered approximately 50% (mock communities) to 80% (gnotobiotic mice) spurious taxa. The fraction of spurious taxa was generally lower based on ASV analysis, but varied depending on the gene region targeted and the barcoding system used. A relative abundance of 0.25% was found as an effective threshold below which the analysis of spurious taxa can be prevented to a large extent in both OTU- and ASV-based analysis approaches. Using this cutoff improved the reproducibility of analysis, i.e., variation in richness estimates was reduced by 38% compared with singleton filtering using six human fecal samples across seven sequencing runs. Beta-diversity analysis of human fecal communities was markedly affected by both the filtering strategy and the type of phylogenetic distances used for comparison, highlighting the importance of carefully analyzing data before drawing conclusions on microbiome changes. In summary, handling of artifact sequences during bioinformatic processing of 16S rRNA gene amplicon data requires careful attention to avoid the generation of misleading findings. We propose the concept of effective richness to facilitate the comparison of alpha-diversity across studies.

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Gut microbiota composition is associated with narcolepsy type 1

Neurology Neuroimmunology & Neuroinflammation ◽

10.1212/nxi.0000000000000896 ◽

2020 ◽

Vol 7 (6) ◽

pp. e896

Author(s):

Alexandre Lecomte ◽

Lucie Barateau ◽

Pedro Pereira ◽

Lars Paulin ◽

Petri Auvinen ◽

...

Keyword(s):

Community Structure ◽

Gut Microbiota ◽

Bacterial Communities ◽

Beta Diversity ◽

Alpha Diversity ◽

Amplicon Sequencing ◽

Rrna Gene ◽

Differential Abundance ◽

Alpha And Beta Diversity

ObjectiveTo test the hypothesis that narcolepsy type 1 (NT1) is related to the gut microbiota, we compared the microbiota bacterial communities of patients with NT1 and control subjects.MethodsThirty-five patients with NT1 (51.43% women, mean age 38.29 ± 19.98 years) and 41 controls (57.14% women, mean age 36.14 ± 12.68 years) were included. Stool samples were collected, and the fecal microbiota bacterial communities were compared between patients and controls using the well-standardized 16S rRNA gene amplicon sequencing approach. We studied alpha and beta diversity and differential abundance analysis between patients and controls, and between subgroups of patients with NT1.ResultsWe found no between-group differences for alpha diversity, but we discovered in NT1 a link with NT1 disease duration. We highlighted differences in the global bacterial community structure as assessed by beta diversity metrics even after adjustments for potential confounders as body mass index (BMI), often increased in NT1. Our results revealed differential abundance of several operational taxonomic units within Bacteroidetes, Bacteroides, and Flavonifractor between patients and controls, but not after adjusting for BMI.ConclusionWe provide evidence of gut microbial community structure alterations in NT1. However, further larger and longitudinal multiomics studies are required to replicate and elucidate the relationship between the gut microbiota, immunity dysregulation and NT1.

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Temporal variation in soil bacterial communities can be confounded with spatial variation

FEMS Microbiology Ecology ◽

10.1093/femsec/fiaa192 ◽

2020 ◽

Vol 96 (12) ◽

Author(s):

Syrie M Hermans ◽

Hannah L Buckley ◽

Fiona Curran-Cournane ◽

Matthew Taylor ◽

Gavin Lear

Keyword(s):

Temporal Variation ◽

Bacterial Communities ◽

Amplicon Sequencing ◽

Spatial Distance ◽

Rrna Gene ◽

Soil Bacterial Communities ◽

Causal Processes ◽

Fundamental Understanding ◽

Soil Bacterial ◽

Indigenous Forest

ABSTRACT Investigating temporal variation in soil bacterial communities advances our fundamental understanding of the causal processes driving biological variation, and how the composition of these important ecosystem members may change into the future. Despite this, temporal variation in soil bacteria remains understudied, and the effects of spatial heterogeneity in bacterial communities on the detection of temporal changes is largely unknown. Using 16S rRNA gene amplicon sequencing, we evaluated temporal patterns in soil bacterial communities from indigenous forest and human-impacted sites sampled repeatedly over a 5-year period. Temporal variation appeared to be greater when fewer spatial samples per site were analysed, as well as in human-impacted compared to indigenous sites (P < 0.01 for both). The biggest portion of variation in bacterial community richness and composition was explained by soil physicochemical variables (13–24%) rather than spatial distance or sampling time (<1%). These results highlight the importance of adequate spatiotemporal replication when sampling soil communities for environmental monitoring, and the importance of conducting temporal research across a wide variety of land uses. This will ensure we have a true understanding of how bacterial communities change over space and time; the work presented here provides important considerations for how such research should be designed.

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Age, gut location and diet impact the gut microbiome of a tropical herbivorous surgeonfish

FEMS Microbiology Ecology ◽

10.1093/femsec/fiz179 ◽

2019 ◽

Author(s):

Lara Parata ◽

Shaun Nielsen ◽

Xing Xing ◽

Torsten Thomas ◽

Suhelen Egan ◽

...

Keyword(s):

Coral Reef ◽

Gastrointestinal Tract ◽

Bacterial Community ◽

Gut Microbiota ◽

Bacterial Communities ◽

Food Source ◽

Amplicon Sequencing ◽

Rrna Gene ◽

Bacterial Symbionts ◽

Adult Fish

Abstract Herbivorous fishes play important ecological roles in coral reefs by consuming algae that can otherwise outcompete corals, but we know little about the gut microbiota that facilitates this process. This study focussed on the gut microbiota of an ecologically important coral reef fish, the convict surgeonfish Acanthurus triostegus. We sought to understand how the microbiome of this species varies along its gastrointestinal tract and how it varies between juvenile and adult fish. Further, we examined if the bacteria associated with the diet consumed by juveniles contributes to the gut microbiota. 16S rRNA gene amplicon sequencing showed that bacterial communities associated with the midgut and hindgut regions were distinct between adults and juveniles, however, no significant differences were seen for gut wall samples. The microbiota associated with the epilithic algal food source was similar to that of the juvenile midgut and gut wall but differed from the microbiome of the hindgut. A core bacterial community including members of taxa Epulopiscium and Brevinemataceae was observed across all gastrointestinal and diet samples, suggesting that these bacterial symbionts can be acquired by juvenile convict surgeonfish horizontally via their diet and then are retained into adulthood.

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Effect of Geography and Captivity on Scat Bacterial Communities in the Imperiled Channel Island Fox

10.21203/rs.3.rs-384378/v1 ◽

2021 ◽

Author(s):

Nicole E Adams ◽

Madeleine A Becker ◽

Suzanne Edmands

Keyword(s):

Bacterial Diversity ◽

Bacterial Communities ◽

Captive Breeding ◽

Interdisciplinary Approach ◽

Amplicon Sequencing ◽

Rrna Gene ◽

Sample Collection ◽

Channel Island ◽

Island Fox ◽

Urocyon Littoralis

Abstract Background With developing understanding that host-associated microbiota play significant roles in individual health and fitness, taking an interdisciplinary approach combining microbiome research with conservation science is increasingly favored. Here we establish the scat microbiome of the imperiled Channel Island fox (Urocyon littoralis) and look at the effects of geography and captivity on the variation in bacterial communities. Results Using high throughput 16S rRNA gene amplicon sequencing, we discovered distinct bacterial communities in each island fox subspecies. Weight, timing of the sample collection, and sex contributed to the geographic patterns. We uncovered significant taxonomic differences and an overall decrease in bacterial diversity in captive versus wild foxes. Conclusions Understanding the drivers of microbial variation in this system provides a valuable lens through which to evaluate the health and conservation of these genetically depauperate foxes. The island-specific bacterial community baselines established in this study can make monitoring island fox health easier and understanding the implications of inter-island translocation clearer. The decrease in bacterial diversity within captive foxes could lead to losses in the functional services normally provided by commensal microbes and suggests that zoos and captive breeding programs would benefit from maintaining microbial diversity.

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Press xenobiotic disturbance favors deterministic assembly with a shift in function and structure of bacterial communities in sludge bioreactors

10.1101/2020.10.15.341966 ◽

2020 ◽

Author(s):

Ezequiel Santillan ◽

Hari Seshan ◽

Stefan Wuertz

Keyword(s):

Community Structure ◽

Bacterial Communities ◽

Temporal Dynamics ◽

Treatment Plant ◽

Amplicon Sequencing ◽

Rrna Gene ◽

Batch Reactors ◽

Function Structure ◽

Community Function ◽

And Function

AbstractDisturbance is thought to affect community assembly mechanisms, which in turn shape community structure and the overall function of the ecosystem. Here, we tested the effect of a continuous (press) xenobiotic disturbance on the function, structure, and assembly of bacterial communities within a wastewater treatment system. Two sets of four-liter sequencing batch reactors were operated in triplicate with and without the addition of 3-chloroaniline for a period of 132 days, following 58 days of acclimation after inoculation with sludge from a full-scale treatment plant. Temporal dynamics of bacterial community structure were derived from 16S rRNA gene amplicon sequencing. Community function, structure and assembly differed between press disturbed and undisturbed reactors. Temporal partitioning of assembly mechanisms via phylogenetic and non-phylogenetic null modelling analysis revealed that deterministic assembly prevailed for disturbed bioreactors, while the role of stochastic assembly was stronger for undisturbed reactors. Our findings are relevant because research spanning various disturbance types, environments and spatiotemporal scales is needed for a comprehensive understanding of the effects of press disturbances on assembly mechanisms, structure, and function of microbial communities.Graphical abstract

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Homogenization of Rhizosphere Bacterial Communities by Pea (Pisum sativum L.) Cultivated under Different Conservation Agricultural Practices in the Eastern Himalayas

10.1101/662775 ◽

2019 ◽

Author(s):

Diptaraj Chaudhari ◽

Krishnappa Rangappa ◽

Anup Das ◽

Jayanta Layek ◽

Savita Basavaraju ◽

...

Keyword(s):

Bacterial Communities ◽

Management Practices ◽

Soil Health ◽

Agricultural Practices ◽

Amplicon Sequencing ◽

Soil Samples ◽

Residue Management ◽

Bulk Soil ◽

Rrna Gene ◽

North East

AbstractConservation agriculture offers a suitable system to harmonize agriculture with the environment, especially in fragile ecosystems of North-East India. Soil microbes play pivotal roles in ecosystem functioning and act as indispensable indicators of overall fitness of crop plant and soil health. Here we demonstrated that altercations in residue management and tillage practices lead to the development of differential bacterial communities forcing the pea plants to recruit special groups of bacteria leading to highly homogenous rhizosphere communities. Pea rhizosphere and bulk soil samples were collected, and bacterial community structure was estimated by 16S rRNA gene amplicon sequencing and predictive functional analysis was performed using Tax4Fun. The effect on pea plants was evident in the bacterial communities as the overall diversity of rhizosphere samples was significantly higher to that of bulk soil samples. Bacillus, Staphylococcus, Planomicrobium, Enterobacter, Arthrobacter, Nitrobacter, Geobacter, and Sphingomonas were noticed as the most abundant genera in the rhizosphere and bulk soil samples. The abundance of Firmicutes and Proteobacteria altered significantly in the rhizosphere and bulk samples, which was further validated by qPCR. Selection of specific taxa by pea plant was indicated by the higher values of mean proportion of Rhizobium, Pseudomonas, Pantoea, Nitrobacter, Enterobacter and Sphingomonas in rhizosphere samples, and Massilia, Paenibacillus and Planomicrobium in bulk soil samples. Tillage and residue management treatments did not significantly alter the bacterial diversity, while their influence was observed on the abundance of few genera. Recorded results revealed that pea plant selects specific taxa into its rhizosphere plausibly to meet its requirements for nutrient uptake and stress amelioration under the different tillage and residue management practices.

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Endophytic bacterial communities and spatiotemporal variations in cotton roots in Xinjiang, China

Canadian Journal of Microbiology ◽

10.1139/cjm-2020-0249 ◽

2020 ◽

Author(s):

Yingwu Shi ◽

Hongmei Yang ◽

Min Chu ◽

Xinxiang Niu ◽

Xiangdong Huo ◽

...

Keyword(s):

Community Structure ◽

Endophytic Bacteria ◽

Amplicon Sequencing ◽

Rrna Gene ◽

Bacterial Populations ◽

Operational Taxonomic Units ◽

Cotton Sample ◽

Endophytic Bacterial Community ◽

V3 Region ◽

Illumina Amplicon Sequencing

Endophytic bacteria may be important for plant health and other ecologically relevant functions of cotton. However, the endophytic bacterial community structure and diversity in cotton is still poorly characterized. We investigated the community structure of endophytic bacteria in cotton roots growing in Xinjiang, China, using the Illumina amplicon sequencing. A total of 60.84 M effective sequences of 16S rRNA gene V3 region were obtained from cotton samples. These sequences revealed huge amount of operational taxonomic units (OTUs) in cotton, that is, 81-338 OTUs in a cotton sample, at 3% cutoff level and sequencing depth of 50000 sequences. We identified 23 classes from the resulting 2,723,384 sequences. Gammaproteobacteria were the dominant class in all cottons, followed by Alphaproteobacteria, Actinobacteria and Bacilli. A marked difference in the diversity of endophytic bacteria in cotton for different growth periods was evident. The greatest number of OTUs was detected during seedling (654 OTUs) and budding (381 OTUs). Endophytic bacteria diversity was reduced during flowering (350 OTUs) and boll-opening (351 OTUs). 217 OTUs were common to all four periods. There were more tags of Pantoea in Shihezi than other locations. While there were more tags of Erwinia in Hami than other locations. The dynamics of endophytic bacteria communities were influenced by plant growth stage. These results show the complexity of the bacterial populations present in inner tissues of cotton.

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Host Species Determines the Composition of the Prokaryotic Microbiota in Phlebotomus Sandflies

Pathogens ◽

10.3390/pathogens9060428 ◽

2020 ◽

Vol 9 (6) ◽

pp. 428

Author(s):

Christos Papadopoulos ◽

Panagiotis A. Karas ◽

Sotirios Vasileiadis ◽

Panagiota Ligda ◽

Anastasios Saratsis ◽

...

Keyword(s):

Gut Microbiota ◽

Host Species ◽

Archaeal Community ◽

Amplicon Sequencing ◽

Structural Effect ◽

Rrna Gene ◽

Host Genotype ◽

Operational Taxonomic Units ◽

Phlebotomine Sandflies ◽

Leishmania Spp

Phlebotomine sandflies are vectors of the humans’ and mammals’ parasite Leishmania spp. Although the role of gut microbiome in the biological cycle of insects is acknowledged, we still know little about the factors modulating the composition of the gut microbiota of sandflies. We tested whether host species impose a strong structural effect on the gut microbiota of Phlebotomus spp. Sandflies were collected from the island of Leros, Greece, and classified to P. papatasi, P. neglectus, P. tobbi, and P. similis, all being negative to Leishmania spp. The prokaryotic gut microbiota was determined via 16S rRNA gene amplicon sequencing. Phlebotomus species supported distinct microbial communities (p < 0.001). P. papatasi microbiota was the most distinct over-dominated by three Spiroplasma, Wolbachia and Paenibacillus operational taxonomic units (OTUs), while another Wolbachia OTU prevailed in P. neglectus. Conversely, the microbiota of P. tobbi and P. similis was composed of several less dominant OTUs. Archaea showed low presence with the dominant OTUs belonging to methanogenic Euryarcheota, ammonia-oxidizing Thaumarcheota, and Nanoarchaeota. We provide first insights into the composition of the bacterial and archaeal community of Phlebotomus sandflies and showed that, in the absence of Leishmania, host genotype is the major modulator of Phlebotomus sandfly gut microbiota.

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