Publications in peer reviewed journals

3 Publications found
  • Recently photoassimilated carbon and fungal-delivered nitrogen are spatially correlated at the cellular scale in the ectomycorrhizal tissue of Fagus sylvatica

    Mayerhofer W, Schintlmeister A, Dietrich M, Gorka S, Wiesenbauer J, Martin V, Gabriel R, Reipert S, Weidinger M, Clode P, Wagner M, Woebken D, Richter A, Kaiser C
    2021 - New Phytologist, in press


    Almost all land plants deliver recently assimilated carbon to mycorrhizal fungi, and receive nutrients in return. The controls of this exchange are, however, not yet fully understood. Here, we investigated if carbon for nitrogen exchange in the ectomycorrhizal symbiosis of Fagus sylvatica is regulated based on reciprocal rewards, and at which spatial scales such a reward mechanism operates.

    We set up a two-source tracing experiment with young ectomycorrhizal beech trees. We analysed the short-time distribution of isotopically labelled recent photosynthates (13CO2) and fungi-delivered nitrogen (15N) across the root system, as well as at the microscopic, cellular scale within an individual mycorrhizal root tip.

    While plants showed only limited control on directing photosynthates towards roots associated with N-delivering fungi, nano-scale secondary ion mass spectrometry (NanoSIMS) analysis of an individual ectomycorrhizal root tip revealed a strong spatial correlation between the distribution of plant-fixed C and fungi-delivered nitrogen. 

    Our results provide first evidence for a reciprocal exchange of C for N between plants and ectomycorrhizal fungi operating at the cellular scale in the ectomycorrhizal tissue. That suggests that individual hyphae emanating from a root tip, that are actively foraging for nutrients may be specifically supported by a greater share of recent photosynthates. 

  • Acidobacteria are active and abundant members of diverse atmospheric H2-oxidizing communities detected in temperate soils

    Giguere AT, Eichorst SA, Meier D, Herbold CW, Richter A, Greening C, Woebken D
    2021 - ISME J, 2: 363-376


    Significant rates of atmospheric H2 consumption have been observed in temperate soils due to the activity of high-affinity enzymes, such as the group 1h [NiFe]-hydrogenase. We designed broadly inclusive primers targeting the large subunit gene (hhyL) of group 1h [NiFe]-hydrogenases for long-read sequencing to explore its taxonomic distribution across soils. This approach revealed a diverse collection of microorganisms harboring hhyL, including previously unknown groups and taxonomically not assignable sequences. Acidobacterial group 1h [NiFe]-hydrogenases genes were abundant and expressed in temperate soils. To support the participation of acidobacteria in H2 consumption, we studied two representative mesophilic soil acidobacteria, which expressed group 1h [NiFe]-hydrogenases and consumed atmospheric H2 during carbon starvation. This is the first time mesophilic acidobacteria, which are abundant in ubiquitous temperate soils, have been shown to oxidize H2 down to below atmospheric concentrations. As this physiology allows bacteria to survive periods of carbon starvation, it could explain the success of soil acidobacteria. With our long-read sequencing approach of group 1h [NiFe]-hydrogenases genes, we show that the ability to oxidize atmospheric levels of His more widely distributed among soil bacteria than previously recognized and could represent a common mechanism enabling bacteria to persist during periods of carbon deprivation.

  • Distribution of mixotrophy and desiccation survival mechanisms across microbial genomes in an arid biological soil crust community

    Meier DV, Imminger S, Gillor O, Woebken D
    2021 - mSystems, in press


    Desert surface soils devoid of plant cover are populated by a variety of microorganisms, many with yet unresolved physiologies and lifestyles. Nevertheless, a common feature vital for these microorganisms inhabiting arid soils is their ability to survive long drought periods and reactivate rapidly in rare incidents of rain. Chemolithotrophic processes such as oxidation of atmospheric hydrogen and carbon monoxide are suggested to be a widespread energy source to support dormancy and resuscitation in desert soil microorganisms. Here, we assessed the distribution of chemolithotrophic, phototrophic, and desiccation-related metabolic potential among microbial populations in arid biological soil crusts (BSCs) from the Negev Desert, Israel, via population-resolved metagenomic analysis. While the potential to utilize light and atmospheric hydrogen as additional energy sources was widespread, carbon monoxide oxidation was less common than expected. The ability to utilize continuously available energy sources might decrease the dependency of mixotrophic populations on organic storage compounds and carbon provided by the BSC-founding cyanobacteria. Several populations from five different phyla besides the cyanobacteria encoded CO2 fixation potential, indicating further potential independence from photoautotrophs. However, we also found population genomes with a strictly heterotrophic genetic repertoire. The highly abundant Rubrobacteraceae (Actinobacteriota) genomes showed particular specialization for this extreme habitat, different from their closest cultured relatives. Besides the ability to use light and hydrogen as energy sources, they encoded extensive O2 stress protection and unique DNA repair potential. The uncovered differences in metabolic potential between individual, co-occurring microbial populations enable predictions of their ecological niches and generation of hypotheses on the dynamics and interactions among them.

Book chapters and other publications

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