Rhizosphere community selection reveals bacteria associated with reduced root disease

Abstract Background: Microbes benefit plants by increasing nutrient availability, producing plant growth hormones, and protecting against pathogens. However, it is largely unknown how plants change root microbial communities.Results: In this study, we used a multi-cycle selection system and infection by the soilborne fungal pathogen Rhizoctonia solani AG8 (hereafter AG8) to examine how plants impact the rhizosphere bacterial community and recruit beneficial microorganisms to suppress soilborne fungal pathogens and promote plant growth. Successive plantings dramatically enhanced disease suppression on susceptible wheat cultivars to AG8 in the greenhouse. Accordingly, analysis of the rhizosphere soil microbial community using deep sequencing of 16S rRNA genes revealed distinct bacterial community profiles assembled over successive wheat plantings. Moreover, the cluster of bacterial communities formed from the AG8-infected rhizosphere was distinct from those without AG8 infection. Interestingly, the bacterial communities from the rhizosphere with the lowest wheat root disease gradually separated from those with the worst wheat root disease over planting cycles. Successive monocultures and application of AG8 increased the abundance of some bacterial genera which have potential antagonistic activities, such as Chitinophaga, Pseudomonas, Chryseobacterium, and Flavobacterium, and a group of plant growth-promoting (PGP) and nitrogen-fixing microbes, including Pedobacter, Variovorax, and Rhizobium. Furthermore, 47 bacteria isolates belong to 35 species were isolated. Among them, eleven and five exhibited antagonistic activities to AG8 and Rhizoctonia oryzae in vitro, respectively. Notably, Janthinobacterium displayed broad antagonism against the soilborne pathogens Pythium ultimum, AG8, and R. oryzae in vitro, and disease suppressive activity to AG8 in soil.Conclusions: Our results demonstrated that successive wheat plantings and pathogen infection can shape the rhizosphere microbial communities and specifically accumulate a group of beneficial microbes. Our findings suggest that soil community selection may offer the potential for addressing agronomic concerns associated with plant diseases and crop productivity.

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Rhizosphere Community Selection Reveals Bacteria Associated With Reduced Root Disease

10.21203/rs.3.rs-64051/v1 ◽

2020 ◽

Author(s):

Chuntao Yin ◽

Juan M. Casa Vargas ◽

Daniel C. Schlatter ◽

Christina H. Hagerty ◽

Scot H. Hulbert ◽

...

Keyword(s):

Bacterial Community ◽

Plant Growth ◽

Microbial Communities ◽

Bacterial Communities ◽

Wheat Root ◽

Root Disease ◽

Plant Diseases ◽

16S Rrna Genes ◽

Rrna Genes

Abstract Background: Microbes benefit plants by increasing nutrient availability, producing plant growth hormones, and protecting against pathogens. However, it is largely unknown how plants change root microbial communities. Results: In this study, we used a multi-cycle selection system and infection by the soilborne fungal pathogen Rhizoctonia solani AG8 (hereafter AG8) to examine how plants impact the rhizosphere bacterial community and recruit beneficial microorganisms to suppress soilborne fungal pathogens and promote plant growth. Successive plantings dramatically enhanced disease suppression on susceptible wheat cultivars to AG8 in the greenhouse. Accordingly, analysis of the rhizosphere soil microbial community using deep sequencing of 16S rRNA genes revealed distinct bacterial community profiles assembled over successive wheat plantings. Moreover, the cluster of bacterial communities formed from the AG8-infected rhizosphere was distinct from those without AG8 infection. Interestingly, the bacterial communities from the rhizosphere with the lowest wheat root disease gradually separated from those with the worst wheat root disease over planting cycles. Successive monocultures and application of AG8 increased the abundance of some bacterial genera which have potential antagonistic activities, such as Chitinophaga, Pseudomonas, Chryseobacterium, and Flavobacterium, and a group of plant growth-promoting (PGP) and nitrogen-fixing microbes, including Pedobacter, Variovorax, and Rhizobium. Furthermore, 47 bacteria isolates belong to 35 species were isolated. Among them, eleven and five exhibited antagonistic activities to AG8 and Rhizoctonia oryzae in vitro, respectively. Notably, Janthinobacterium displayed broad antagonism against the soilborne pathogens Pythium ultimum, AG8, and R. oryzae in vitro, and disease suppressive activity to AG8 in soil. Conclusions: Our results demonstrated that successive wheat plantings and pathogen infection can shape the rhizosphere microbial communities and specifically accumulate a group of beneficial microbes. Our findings suggest that soil community selection may offer the potential for addressing agronomic concerns associated with plant diseases and crop productivity.

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Rhizosphere community selection reveals bacteria associated with reduced root disease

Microbiome ◽

10.1186/s40168-020-00997-5 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Chuntao Yin ◽

Juan M. Casa Vargas ◽

Daniel C. Schlatter ◽

Christina H. Hagerty ◽

Scot H. Hulbert ◽

...

Keyword(s):

Bacterial Community ◽

Plant Growth ◽

Microbial Communities ◽

Bacterial Communities ◽

Wheat Root ◽

Root Disease ◽

Plant Diseases ◽

16S Rrna Genes ◽

Rrna Genes

Abstract Background Microbes benefit plants by increasing nutrient availability, producing plant growth hormones, and protecting against pathogens. However, it is largely unknown how plants change root microbial communities. Results In this study, we used a multi-cycle selection system and infection by the soilborne fungal pathogen Rhizoctonia solani AG8 (hereafter AG8) to examine how plants impact the rhizosphere bacterial community and recruit beneficial microorganisms to suppress soilborne fungal pathogens and promote plant growth. Successive plantings dramatically enhanced disease suppression on susceptible wheat cultivars to AG8 in the greenhouse. Accordingly, analysis of the rhizosphere soil microbial community using deep sequencing of 16S rRNA genes revealed distinct bacterial community profiles assembled over successive wheat plantings. Moreover, the cluster of bacterial communities formed from the AG8-infected rhizosphere was distinct from those without AG8 infection. Interestingly, the bacterial communities from the rhizosphere with the lowest wheat root disease gradually separated from those with the worst wheat root disease over planting cycles. Successive monocultures and application of AG8 increased the abundance of some bacterial genera which have potential antagonistic activities, such as Chitinophaga, Pseudomonas, Chryseobacterium, and Flavobacterium, and a group of plant growth-promoting (PGP) and nitrogen-fixing microbes, including Pedobacter, Variovorax, and Rhizobium. Furthermore, 47 bacteria isolates belong to 35 species were isolated. Among them, eleven and five exhibited antagonistic activities to AG8 and Rhizoctonia oryzae in vitro, respectively. Notably, Janthinobacterium displayed broad antagonism against the soilborne pathogens Pythium ultimum, AG8, and R. oryzae in vitro, and disease suppressive activity to AG8 in soil. Conclusions Our results demonstrated that successive wheat plantings and pathogen infection can shape the rhizosphere microbial communities and specifically accumulate a group of beneficial microbes. Our findings suggest that soil community selection may offer the potential for addressing agronomic concerns associated with plant diseases and crop productivity.

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Rhizosphere community selection reveals bacteria associated with reduced root disease

10.21203/rs.3.rs-64051/v2 ◽

2020 ◽

Author(s):

Timothy Paulitz ◽

Chuntao Yin ◽

Juan M. Casa Vargas ◽

Daniel C. Schlatter ◽

Christina H. Hagerty ◽

...

Keyword(s):

Bacterial Community ◽

Plant Growth ◽

Microbial Communities ◽

Bacterial Communities ◽

Wheat Root ◽

Root Disease ◽

Plant Diseases ◽

16S Rrna Genes ◽

Rrna Genes

Abstract Background: Microbes benefit plants by increasing nutrient availability, producing plant growth hormones, and protecting against pathogens. However, it is largely unknown how plants change root microbial communities. Results: In this study, we used a multi-cycle selection system and infection by the soilborne fungal pathogen Rhizoctonia solani AG8 (hereafter AG8) to examine how plants impact the rhizosphere bacterial community and recruit beneficial microorganisms to suppress soilborne fungal pathogens and promote plant growth. Successive plantings dramatically enhanced disease suppression on susceptible wheat cultivars to AG8 in the greenhouse. Accordingly, analysis of the rhizosphere soil microbial community using deep sequencing of 16S rRNA genes revealed distinct bacterial community profiles assembled over successive wheat plantings. Moreover, the cluster of bacterial communities formed from the AG8-infected rhizosphere was distinct from those without AG8 infection. Interestingly, the bacterial communities from the rhizosphere with the lowest wheat root disease gradually separated from those with the worst wheat root disease over planting cycles. Successive monocultures and application of AG8 increased the abundance of some bacterial genera which have potential antagonistic activities, such as Chitinophaga, Pseudomonas, Chryseobacterium, and Flavobacterium, and a group of plant growth-promoting (PGP) and nitrogen-fixing microbes, including Pedobacter, Variovorax, and Rhizobium. Furthermore, 47 bacteria isolates belong to 35 species were isolated. Among them, eleven and five exhibited antagonistic activities to AG8 and Rhizoctonia oryzae in vitro, respectively. Notably, Janthinobacterium displayed broad antagonism against the soilborne pathogens Pythium ultimum, AG8, and R. oryzae in vitro, and disease suppressive activity to AG8 in soil. Conclusions: Our results demonstrated that successive wheat plantings and pathogen infection can shape the rhizosphere microbial communities and specifically accumulate a group of beneficial microbes. Our findings suggest that soil community selection may offer the potential for addressing agronomic concerns associated with plant diseases and crop productivity.

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Coupling Root Diameter With Rooting Depth to Reveal the Heterogeneous Assembly of Root-Associated Bacterial Communities in Soybean

Frontiers in Microbiology ◽

10.3389/fmicb.2021.783563 ◽

2021 ◽

Vol 12 ◽

Author(s):

Wen Luo ◽

Xiaoyu Zai ◽

Jieyu Sun ◽

Da Li ◽

Yuanli Li ◽

...

Keyword(s):

Bacterial Community ◽

Microbial Communities ◽

Bacterial Communities ◽

Plant Root ◽

Alpha Diversity ◽

Amplicon Sequencing ◽

Root Diameter ◽

16S Rrna Genes ◽

Rrna Genes ◽

Rooting Depth

Root diameter and rooting depth lead to morphological and architectural heterogeneity of plant roots; however, little is known about their effects on root-associated microbial communities. Bacterial community assembly was explored across 156 samples from three rhizocompartments (the rhizosphere, rhizoplane, and endosphere) for different diameters (0.0–0.5 mm, 0.5–1.0 mm, 1.0–2.0 mm, and>2.0 mm) and depths (0–5 cm, 5–10 cm, 10–15 cm, and 15–20 cm) of soybean [Glycine max (L.) Merrill] root systems. The microbial communities of all samples were analyzed using amplicon sequencing of bacterial 16S rRNA genes. The results showed that root diameter significantly affected the rhizosphere and endosphere bacterial communities, while rooting depth significantly influenced the rhizosphere and rhizoplane bacterial communities. The bacterial alpha diversity decreased with increasing root diameter in all three rhizocompartments, and the diversity increased with increasing rooting depth only in the rhizoplane. Clearly, the hierarchical enrichment process of the bacterial community showed a change from the rhizosphere to the rhizoplane to the endosphere, and the bacterial enrichment was higher in thinner or deeper roots (except for the roots at a depth of 15–20 cm). Network analysis indicated that thinner or deeper roots led to higher bacterial network complexity. The core and keystone taxa associated with the specific root diameter class and rooting depth class harbored specific adaptation or selection strategies. Root diameter and rooting depth together affected the root-associated bacterial assembly and network complexity in the root system. Linking root traits to microbiota may enhance our understanding of plant root-microbe interactions and their role in developing environmentally resilient root ecosystems.

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Diversity and Dynamics of Seaweed Associated Microbial Communities Inhabiting the Lagoon of Venice

Microorganisms ◽

10.3390/microorganisms8111657 ◽

2020 ◽

Vol 8 (11) ◽

pp. 1657

Author(s):

Abdul-Salam Juhmani ◽

Alessandro Vezzi ◽

Mohammad Wahsha ◽

Alessandro Buosi ◽

Fabio De Pascale ◽

...

Keyword(s):

Microbial Communities ◽

Bacterial Communities ◽

Host Response ◽

Environmental Parameters ◽

16S Rrna Genes ◽

Rrna Genes ◽

Nutrient Concentrations ◽

Lagoon Of Venice ◽

Anthropogenic Stressors ◽

Rich Diversity

Seaweeds are a group of essential photosynthetic organisms that harbor a rich diversity of associated microbial communities with substantial functions related to host health and defense. Environmental and anthropogenic stressors may disrupt the microbial communities and their metabolic activity, leading to host physiological alterations that negatively affect seaweeds’ performance and survival. Here, the bacterial communities associated with one of the most common seaweed, Ulva laetevirens Areshough, were sampled over a year at three sites of the lagoon of Venice affected by different environmental and anthropogenic stressors. Bacterial communities were characterized through Illumina sequencing of the V4 hypervariable region of 16S rRNA genes. The study demonstrated that the seaweed associated bacterial communities at sites impacted by environmental stressors were host-specific and differed significantly from the less affected site. Furthermore, these communities were significantly distinct from those of the surrounding seawater. The bacterial communities’ composition was significantly correlated with environmental parameters (nutrient concentrations, dissolved oxygen saturation, and pH) across sites. This study showed that several more abundant bacteria on U. laetevirens at stressed sites belonged to taxa related to the host response to the stressors. Overall, environmental parameters and anthropogenic stressors were shown to substantially affect seaweed associated bacterial communities, which reflect the host response to environmental variations.

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Tagging Frogs with Passive Integrated Transponders Causes Disruption of the Cutaneous Bacterial Community and Proliferation of Opportunistic Fungi

Applied and Environmental Microbiology ◽

10.1128/aem.01175-14 ◽

2014 ◽

Vol 80 (15) ◽

pp. 4779-4784 ◽

Cited By ~ 11

Author(s):

Rachael E. Antwis ◽

Gerardo Garcia ◽

Andrea L. Fidgett ◽

Richard F. Preziosi

Keyword(s):

Bacterial Community ◽

Microbial Communities ◽

Bacterial Communities ◽

Pathogenic Fungus ◽

Fold Increase ◽

Bacterial Strains ◽

Opportunistic Fungi ◽

Content Type ◽

Pit Tagging

ABSTRACTSymbiotic bacterial communities play a key role in protecting amphibians from infectious diseases including chytridiomycosis, caused by the pathogenic fungusBatrachochytrium dendrobatidis. Events that lead to the disruption of the bacterial community may have implications for the susceptibility of amphibians to such diseases. Amphibians are often marked both in the wild and in captivity for a variety of reasons, and although existing literature indicates that marking techniques have few negative effects, the response of cutaneous microbial communities has not yet been investigated. Here we determine the effects of passive integrated transponder (PIT) tagging on culturable cutaneous microbial communities of captive Morelet's tree frogs (Agalychnis moreletii) and assess the isolated bacterial strains for anti-B. dendrobatidisactivityin vitro. We find that PIT tagging causes a major disruption to the bacterial community associated with the skin of frogs (∼12-fold increase in abundance), as well as a concurrent proliferation in resident fungi (up to ∼200-fold increase). Handling also caused a disruption the bacterial community, although to a lesser extent than PIT tagging. However, the effects of both tagging and handling were temporary, and after 2 weeks, the bacterial communities were similar to their original compositions. We also identify two bacterial strains that inhibitB. dendrobatidis, one of which increased in abundance on PIT-tagged frogs at 1 day postmarking, while the other was unaffected. These results show that PIT tagging has previously unobserved consequences for cutaneous microbial communities of frogs and may be particularly relevant for studies that intend to use PIT tagging to identify individuals involved in trials to develop probiotic treatments.

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The Effect of a Sublethal Temperature Elevation on the Structure of Bacterial Communities Associated with the CoralPorites compressa

Journal of Marine Biology ◽

10.1155/2011/969173 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 6

Author(s):

Jennifer L. Salerno ◽

Dan R. Reineman ◽

Ruth D. Gates ◽

Michael S. Rappé

Keyword(s):

Community Structure ◽

Bacterial Community ◽

Bacterial Communities ◽

Bacterial Community Structure ◽

16S Rrna Genes ◽

Rrna Genes ◽

Polymorphism Analysis ◽

Significant Shift ◽

Coral Host ◽

Experimental Conditions

Evidence points to a link between environmental stressors, coral-associated bacteria, and coral disease; however, few studies have examined the details of this relationship under tightly controlled experimental conditions. To address this gap, an array of closed-system, precision-controlled experimental aquaria were used to investigate the effects of an abrupt 1°C above summer ambient temperature increase on the bacterial community structure and photophysiology ofPorites compressacorals. While the temperature treatment rapidly impacted the photophysiology of the coral host, it did not elicit a statistically significant shift in bacterial community structure from control, untreated corals as determined by terminal restriction fragment length polymorphism analysis of 16S rRNA genes. Two of three coral colonies harbored more closely related bacterial communities at the time of collection and, despite statistically significant shifts in bacterial community structure for both control and treatment corals during the 10-day acclimation period, maintained this relationship over the course of the experiment. The experimental design used in this study proved to be a robust, reproducible system for investigating coral microbiology in an aquarium setting.

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ENDOPHYTES: STRUCTURAL AND FUNCTIONAL DIVERSITY AND BIOTECHNOLOGICAL APPLICATIONS IN CONTROL OF PLANT PATHOGENS

Ecological genetics ◽

10.17816/ecogen6217-26 ◽

2008 ◽

Vol 6 (2) ◽

pp. 17-26 ◽

Cited By ~ 3

Author(s):

Gabriele Berg ◽

Henry M?ller ◽

Christin Zachow ◽

Katja Opelt ◽

Katja Scherwinski ◽

...

Keyword(s):

Bacterial Communities ◽

Endophytic Bacteria ◽

Host Plants ◽

Plant Pathogens ◽

16S Rrna Genes ◽

Rrna Genes ◽

Serratia Plymuthica ◽

In Situ Conditions ◽

Antagonistic Potential

Endophytes are an interesting group of plant-associated bacteria that live inside plants and show neutral or beneficial interaction with their host plants. The structure of bacterial communities in endophytic microenvironments of important crops (different cultivars of potato, lettuce, and sugar beet) and native plants (different bryophyte species) was analyzed by a multiphasic approach at different field sites in Europe. Interestingly, results of the cultivation-independent approaches using Single-Strand Conformation Polymorphism (SSCP) and/or Terminal Restriction Fragments Length Polymorphism (T-RFLP) of 16S rRNA genes amplified by universal as well as group-specific and functional primers revealed a high diversity and specificity of endophytic bacterial communities. The antagonistic potential of endophytic bacteria, which was determined by screening for in vitro antagonism against different pathogens (bacteria, fungi, protists, and nematodes) ranged from 5 to 43 %. An impressive, phylogenetically diverse spectrum of antagonistic strains was found. The indigenous antagonistic potential of endophytic bacteria was influenced by the plant genotype and developmental stage, the internal microenvironment, and the soil type. A screening strategy for biocontrol strains resulted in the selection of promising candidates. These strains were evaluated in greenhouse and field trials regarding their efficiency to control pathogens under in situ conditions. One product (RhizoStar®) on the basis of serratia plymuthica HRO-C48 to control Verticillium wilt on different host plants was developed. For other promising candidates likePseudomonas trivialis 3Re2-7 (B3) and serratia plymuthica 3Re4-18 (B4) a biological control strategy against the soil-borne pathogen Rhizoctonia solani will be established. These studies were funded by the Deutsche Forschungs-gemeinschaft, the Ministry of Consumer Protection, Food and Agriculture (Germany) and by private industries (KWS SAAT AG, Strawberry farm Rovershagen, and Nor-ddeutsche Pflanzenzucht Hans-Georg Lembke KG, Ho-henlieth, Germany) by grants to G.B.

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Axial Dynamics, Stability, and Interspecies Similarity of Bacterial Community Structure in the Highly Compartmentalized Gut of Soil-Feeding Termites (Cubitermes spp.)

Applied and Environmental Microbiology ◽

10.1128/aem.69.10.6018-6024.2003 ◽

2003 ◽

Vol 69 (10) ◽

pp. 6018-6024 ◽

Cited By ~ 65

Author(s):

Dirk Schmitt-Wagner ◽

Michael W. Friedrich ◽

Bianca Wagner ◽

Andreas Brune

Keyword(s):

Community Structure ◽

Bacterial Community ◽

Bacterial Communities ◽

Bacterial Community Structure ◽

Rflp Analysis ◽

Companion Paper ◽

16S Rrna Genes ◽

Rrna Genes ◽

Molecular Fingerprints ◽

Physicochemical Conditions

ABSTRACT The highly compartmentalized gut of soil-feeding termites is characterized by pronounced axial dynamics in physicochemical conditions and microbial processes. In a companion paper (D. Schmitt-Wagner, M. W. Friedrich, B. Wagner, and A. Brune, Appl. Environ. Microbiol. 69:6007-6017, 2003), we demonstrated that the variety of physicochemical conditions in the different gut compartments of Cubitermes spp. is reflected in the diversity of the respective intestinal microbial communities. Here, we used molecular fingerprints of 16S rRNA genes of the bacterial community, obtained by terminal restriction fragment length polymorphism (T-RFLP) analysis, to describe the axial dynamics of the bacterial community structure in the different gut sections. Comparison of the T-RFLP profiles with the predicted terminal restriction fragments of the clones in clone libraries of the gut segments in Cubitermes orthognathus confirmed that all hindgut sections harbored distinct bacterial communities. Morisita indices of community similarity, calculated by comparing the different patterns, revealed large differences between the bacterial communities of soil, gut, and nest material and also among the individual gut sections. By contrast, comparison of the homologous gut segments of different Cubitermes species indicated that the three termite species investigated possessed a similar, gut-specific microbiota that remained comparatively stable even during several months of maintenance in the laboratory.

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Robust Hydrocarbon Degradation and Dynamics of Bacterial Communities during Nutrient-Enhanced Oil Spill Bioremediation

Applied and Environmental Microbiology ◽

10.1128/aem.68.11.5537-5548.2002 ◽

2002 ◽

Vol 68 (11) ◽

pp. 5537-5548 ◽

Cited By ~ 321

Author(s):

Wilfred F. M. Röling ◽

Michael G. Milner ◽

D. Martin Jones ◽

Kenneth Lee ◽

Fabien Daniel ◽

...

Keyword(s):

Bacterial Community ◽

16S Rrna ◽

Oil Spill ◽

Bacterial Communities ◽

Inorganic Nutrients ◽

16S Rrna Genes ◽

Rrna Genes ◽

Oil Degradation ◽

Beach Sediment ◽

Wide Range

ABSTRACT Degradation of oil on beaches is, in general, limited by the supply of inorganic nutrients. In order to obtain a more systematic understanding of the effects of nutrient addition on oil spill bioremediation, beach sediment microcosms contaminated with oil were treated with different levels of inorganic nutrients. Oil biodegradation was assessed respirometrically and on the basis of changes in oil composition. Bacterial communities were compared by numerical analysis of denaturing gradient gel electrophoresis (DGGE) profiles of PCR-amplified 16S rRNA genes and cloning and sequencing of PCR-amplified 16S rRNA genes. Nutrient amendment over a wide range of concentrations significantly improved oil degradation, confirming that N and P limited degradation over the concentration range tested. However, the extent and rate of oil degradation were similar for all microcosms, indicating that, in this experiment, it was the addition of inorganic nutrients rather than the precise amount that was most important operationally. Very different microbial communities were selected in all of the microcosms. Similarities between DGGE profiles of replicate samples from a single microcosm were high (95% ± 5%), but similarities between DGGE profiles from replicate microcosms receiving the same level of inorganic nutrients (68% ± 5%) were not significantly higher than those between microcosms subjected to different nutrient amendments (63% ± 7%). Therefore, it is apparent that the different communities selected cannot be attributed to the level of inorganic nutrients present in different microcosms. Bioremediation treatments dramatically reduced the diversity of the bacterial community. The decrease in diversity could be accounted for by a strong selection for bacteria belonging to the alkane-degrading Alcanivorax/Fundibacter group. On the basis of Shannon-Weaver indices, rapid recovery of the bacterial community diversity to preoiling levels of diversity occurred. However, although the overall diversity was similar, there were considerable qualitative differences in the community structure before and after the bioremediation treatments.

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