scholarly journals Arabidopsis sculpt distinct root-associated microbiomes through the synthesis of secondary metabolites and defense signaling molecules

2020 ◽  
Author(s):  
Enoch Narh Kudjordjie ◽  
Rumakanta Sapkota ◽  
Mogens Nicolaisen
Keyword(s):  
Signaling Pathways ◽  
Plant Root ◽  
Amplicon Sequencing ◽  
Signaling Molecules ◽  
Natural Soil ◽  
Community Structures ◽  
Arabidopsis Mutants ◽  
Defense Signaling ◽  
Microbial Community Structures ◽  
Microbiome Assembly

Abstract Background Plant mutants with alterations in specific biosynthetic or signaling pathways exhibit distinct biochemical or physiological traits and are, thus, suitable models for studying links between the plant and its associated microbiota. Here, we examined microbial community structures of a range of Arabidopsis thaliana mutants disrupted in metabolic pathways for the production of glucosinolates, flavonoids, or a number of defense signaling molecules. Arabidopsis mutants and their background wild types (controls) were grown in natural soil and maintained in a greenhouse for 4 weeks before collection of roots for microbiome analysis. We characterized bacterial and fungal communities using 16S rRNA and fungal ITS amplicon sequencing, respectively. Results Our results showed that the Arabidopsis mutants had distinct microbial profiles compared to control plants. The relative abundances of the bacterial classes Actinobacteria, Thermoleophilia and Verrucomicrobiae, and the fungal classes Eurotiomycetes and Sordariomycetes were the most affected when comparing mutants and their wild types. At the genus level, the bacterial taxa Azospirillum, Fluviicola, and Flavobacterium were significantly enriched in most glucosinolate, flavonoid and signaling mutants while the fungal taxa Sporobolomyces and Emericellopsis were enriched in several glucosinolate and defense signaling mutants. Conclusion By using different Arabidopsis mutants and their background controls, we showed that plant secondary metabolism and defense signaling molecules affect bacterial and fungal community structures. We conclude that disruption of pathways for secondary metabolite production or disruption of defense signaling pathways affected the innate mechanisms that modulate plant root-associated microbiome assembly.

scholarly journals High-throughput amplicon sequencing reveals the spatiotemporal effects, abiotic and biotic shaping factors for the microbial communities in tropical mangrove sediments in Sanya, China

2020 ◽  
Author(s):  
Wu Qu ◽  
Boliang Gao ◽  
Jie Wu ◽  
Min Jin ◽  
Jianxin Wang ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Fungal Community ◽  
Amplicon Sequencing ◽  
Biotic Factors ◽  
Community Structures ◽  
Mangrove Sediments ◽  
Element Cycling ◽  
Microbial Community Structures

Abstract Background Microbial roles in element cycling and nutrient providing are crucial for mangrove ecosystems and serve as important regulators for climate change in Earth ecosystem. However, some key information about the spatiotemporal influences and abiotic and biotic shaping factors for the microbial communities in mangrove sediments remains lacking. Methods In this work, 22 sediment samples were collected from multiple spatiotemporal dimensions, including three locations, two depths, and four seasons, and the bacterial, archaeal, and fungal community structures in these samples were studied using amplicon sequencing. Results The microbial community structures were varied in the samples from different depths and locations based on the results of LDA effect size analysis, principal coordinate analysis, the analysis of similarities, and permutational multivariate ANOVA. However, these microbial community structures were stable among the seasonal samples. Linear fitting models and Mantel test showed that among the 13 environmental factors measured in this study, the sediment particle size (PS) was the key abiotic shaping factor for the bacterial, archaeal, or fungal community structure. Besides PS, salinity and humidity were also significant impact factors according to the canonical correlation analysis (p ≤ 0.05). Co-occurrence networks demonstrated that the bacteria assigned into phyla Ignavibacteriae, Proteobacteria, Bacteroidetes, Chloroflexi, and Acidobacteria were the key biotic factors for shaping the bacterial community in mangrove sediments. Conclusions This work showed the variability on spatial dimensions and the stability on temporal dimension for the bacterial, archaeal, or fungal microbial community structure, indicating that the tropical mangrove sediments are versatile but stable environments. PS served as the key abiotic factor could indirectly participate in material circulation in mangroves by influencing microbial community structures, along with salinity and humidity. The bacteria as key biotic factors were found with the abilities of photosynthesis, polysaccharide degradation, or nitrogen fixation, which were potential indicators for monitoring mangrove health, as well as crucial participants in the storage of mangrove blue carbons and mitigation of climate warming. This study expanded the knowledge of mangroves for the spatiotemporal variation, distribution, and regulation of the microbial community structures, thus further elucidating the microbial roles in mangrove management and climate regulation.

scholarly journals Arabidopsis assemble distinct root-associated microbiomes through the synthesis of an array of defense metabolites

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0259171
Author(s):  
Enoch Narh Kudjordjie ◽  
Rumakanta Sapkota ◽  
Mogens Nicolaisen
Keyword(s):  
Metabolic Pathways ◽  
Plant Production ◽  
Natural Soil ◽  
Signalling Molecules ◽  
Community Profiling ◽  
Microbial Community Structures ◽  
Parental Lines ◽  
Resource Data ◽  
The Individual ◽  
Microbiome Assembly

Plant associated microbiomes are known to confer fitness advantages to the host. Understanding how plant factors including biochemical traits influence host associated microbiome assembly could facilitate the development of microbiome-mediated solutions for sustainable plant production. Here, we examined microbial community structures of a set of well-characterized Arabidopsis thaliana mutants disrupted in metabolic pathways for the production of glucosinolates, flavonoids, or a number of defense signalling molecules. A. thaliana lines were grown in a natural soil and maintained under greenhouse conditions for 4 weeks before collection of roots for bacterial and fungal community profiling. We found distinct relative abundances and diversities of bacterial and fungal communities assembled in the individual A. thaliana mutants compared to their parental lines. Bacterial and fungal genera were mostly enriched than depleted in secondary metabolite and defense signaling mutants, except for flavonoid mutations on fungi communities. Bacterial genera Azospirillum and Flavobacterium were significantly enriched in most of the glucosinolate, flavonoid and signalling mutants while the fungal taxa Sporobolomyces and Emericellopsis were enriched in several glucosinolates and signalling mutants. Whilst the present study revealed marked differences in microbiomes of Arabidopsis mutants and their parental lines, it is suggestive that unknown enzymatic and pleiotropic activities of the mutated genes could contribute to the identified host-associated microbiomes. Notwithstanding, this study revealed interesting gene-microbiota links, and thus represents valuable resource data for selecting candidate A. thaliana mutants for analyzing the links between host genetics and the associated microbiome.

scholarly journals Coordination of microbe–host homeostasis by crosstalk with plant innate immunity

Nature Plants ◽  
2021 ◽  
Author(s):  
Ka-Wai Ma ◽  
Yulong Niu ◽  
Yong Jia ◽  
Jana Ordon ◽  
Charles Copeland ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Amplicon Sequencing ◽  
Host Susceptibility ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Root Growth Inhibition ◽  
Natural Soil ◽  
Molecular Pattern ◽  
Immune Related Genes ◽  
Molecular Patterns

AbstractPlants grown in natural soil are colonized by phylogenetically structured communities of microbes known as the microbiota. Individual microbes can activate microbe-associated molecular pattern (MAMP)-triggered immunity (MTI), which limits pathogen proliferation but curtails plant growth, a phenomenon known as the growth–defence trade-off. Here, we report that, in monoassociations, 41% (62 out of 151) of taxonomically diverse root bacterial commensals suppress Arabidopsis thaliana root growth inhibition (RGI) triggered by immune-stimulating MAMPs or damage-associated molecular patterns. Amplicon sequencing of bacterial 16S rRNA genes reveals that immune activation alters the profile of synthetic communities (SynComs) comprising RGI-non-suppressive strains, whereas the presence of RGI-suppressive strains attenuates this effect. Root colonization by SynComs with different complexities and RGI-suppressive activities alters the expression of 174 core host genes, with functions related to root development and nutrient transport. Furthermore, RGI-suppressive SynComs specifically downregulate a subset of immune-related genes. Precolonization of plants with RGI-suppressive SynComs, or mutation of one commensal-downregulated transcription factor, MYB15, renders the plants more susceptible to opportunistic Pseudomonas pathogens. Our results suggest that RGI-non-suppressive and RGI-suppressive root commensals modulate host susceptibility to pathogens by either eliciting or dampening MTI responses, respectively. This interplay buffers the plant immune system against pathogen perturbation and defence-associated growth inhibition, ultimately leading to commensal–host homeostasis.

scholarly journals Microbial Population Changes during Bioremediation of an Experimental Oil Spill

1999 ◽  
Vol 65 (8) ◽  
pp. 3566-3574 ◽  
Author(s):  
Sarah J. MacNaughton ◽  
John R. Stephen ◽  
Albert D. Venosa ◽  
Gregory A. Davis ◽  
Yun-Juan Chang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Bacterial Community ◽  
Oil Spill ◽  
Phospholipid Fatty Acid ◽  
Community Structures ◽  
Gram Negative ◽  
Dgge Analysis ◽  
16S Rdna Pcr ◽  
Microbial Community Structures ◽  
Plfa Analysis

ABSTRACT Three crude oil bioremediation techniques were applied in a randomized block field experiment simulating a coastal oil spill. Four treatments (no oil control, oil alone, oil plus nutrients, and oil plus nutrients plus an indigenous inoculum) were applied. In situ microbial community structures were monitored by phospholipid fatty acid (PLFA) analysis and 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) to (i) identify the bacterial community members responsible for the decontamination of the site and (ii) define an end point for the removal of the hydrocarbon substrate. The results of PLFA analysis demonstrated a community shift in all plots from primarily eukaryotic biomass to gram-negative bacterial biomass with time. PLFA profiles from the oiled plots suggested increased gram-negative biomass and adaptation to metabolic stress compared to unoiled controls. DGGE analysis of untreated control plots revealed a simple, dynamic dominant population structure throughout the experiment. This banding pattern disappeared in all oiled plots, indicating that the structure and diversity of the dominant bacterial community changed substantially. No consistent differences were detected between nutrient-amended and indigenous inoculum-treated plots, but both differed from the oil-only plots. Prominent bands were excised for sequence analysis and indicated that oil treatment encouraged the growth of gram-negative microorganisms within the α-proteobacteria andFlexibacter-Cytophaga-Bacteroides phylum. α-Proteobacteria were never detected in unoiled controls. PLFA analysis indicated that by week 14 the microbial community structures of the oiled plots were becoming similar to those of the unoiled controls from the same time point, but DGGE analysis suggested that major differences in the bacterial communities remained.

Sign in / Sign up

Export Citation Format

Share Document