| 1. |
- Andresen, Louise C., 1974, et al.
(författare)
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Patterns of free amino acids in tundra soils reflect mycorrhizal type, shrubification, and warming
- 2022
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 0940-6360 .- 1432-1890. ; 32:3-4, s. 305-313
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Tidskriftsartikel (refereegranskat)abstract
- The soil nitrogen (N) cycle in cold terrestrial ecosystems is slow and organically bound N is an important source of N for plants in these ecosystems. Many plant species can take up free amino acids from these infertile soils, either directly or indirectly via their mycorrhizal fungi. We hypothesized that plant community changes and local plant community differences will alter the soil free amino acid pool and composition; and that long-term warming could enhance this effect. To test this, we studied the composition of extractable free amino acids at five separate heath, meadow, and bog locations in subarctic and alpine Scandinavia, with long-term (13 to 24 years) warming manipulations. The plant communities all included a mixture of ecto-, ericoid-, and arbuscular mycorrhizal plant species. Vegetation dominated by grasses and forbs with arbuscular and non-mycorrhizal associations showed highest soil free amino acid content, distinguishing them from the sites dominated by shrubs with ecto- and ericoid-mycorrhizal associations. Warming increased shrub and decreased moss cover at two sites, and by using redundancy analysis, we found that altered soil free amino acid composition was related to this plant cover change. From this, we conclude that the mycorrhizal type is important in controlling soil N cycling and that expansion of shrubs with ectomycorrhiza (and to some extent ericoid mycorrhiza) can help retain N within the ecosystems by tightening the N cycle.
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| 2. |
- Berner, Christoffer, et al.
(författare)
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Long-term effect of apatite on ectomycorrhizal growth and community structure.
- 2012
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 1432-1890 .- 0940-6360. ; 22:8, s. 615-621
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Tidskriftsartikel (refereegranskat)abstract
- Ectomycorrhizal (ECM) fungi are efficient at taking up phosphorus (P) from mineral sources, such as apatite, which are not easily available to the host trees. Since ECM fungal species differ in P uptake rates, it can be expected that the composition of the ECM fungal community will change upon exposure to apatite, provided that the P transfer is rewarded by more carbon being transferred to the fungal symbiont. Control and apatite-amended mesh bags were buried in pairs in the humus layer of a P-poor Norway spruce forest. The ECM fungal community that colonized these bags was analyzed by DNA extraction, PCR amplification of the internal transcribed spacer (ITS) region, cloning, and random sequencing. Fungal biomass was estimated by ergosterol analysis. No change in the ECM fungal community structure was seen after 5 years of apatite exposure, although the fungal biomass increased threefold upon apatite amendment. Our results indicate that host trees enhance carbon allocation to ECM fungi colonizing P sources in P-poor forests but the lack of change in the composition of the ECM fungal community suggests that P transfer rates were similar among the species. Alternatively, higher P transfer among certain species was not rewarded with higher carbon transfer from the host.
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| 3. |
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| 4. |
- Castaño Soler, Carles
(författare)
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White mulch and irrigation increase black truffle soil mycelium when competing with summer truffle in young truffle orchards
- 2021
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 0940-6360 .- 1432-1890. ; 31, s. 371-382
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Tidskriftsartikel (refereegranskat)abstract
- The black truffle (Tuber melanosporum Vittad.) and the summer truffle (Tuber aestivum Vittad.) are two of the most appreciated edible fungi worldwide. The natural distributions of both species partially overlap. However, the interspecific interactions between these truffles and how irrigation and mulching techniques impact the dynamics between them are still unknown. Here, an experimental truffle plantation with Quercus ilex was established in Maials (Catalonia, Spain), combining three soil mulch treatments (white mulch, black mulch and bare soil as a control) and two irrigation regimes (irrigated and non-irrigated as a control) to investigate truffle mycelial dynamics in soil when both truffle species co-occur. The development of truffle mycelium in two different seasons (spring and autumn) in two consecutive years (2017 and 2018) was quantified using qPCR. Truffle mycelia of both species showed greatest development under white mulch. When mycelia of both truffle species co-occurred in soil, irrigation combined with white mulch resulted in greater quantities of T. melanosporum mycelial biomass, whereas the control irrigation treatment favoured the development of T. aestivum. Mulch treatments were also advantageous for seedling growth, which was expressed as root collar diameter and its increment during the study period. Significant relationships between root collar diameter and root growth and the amount of mycelial biomass in the soil were observed for both truffle species. Our results indicate the potential advantages of using white mulch to support irrigation in truffle plantations located in areas with dry Mediterranean climatic conditions to promote the development of Tuber mycelium.
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| 5. |
- Dunham, S. M., et al.
(författare)
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Species richness and community composition of mat-forming ectomycorrhizal fungi in old- and second-growth Douglas-fir forests of the HJ Andrews Experimental Forest, Oregon, USA
- 2007
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 0940-6360 .- 1432-1890. ; 17:8, s. 633-645
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the species identity of mat-forming ectomycorrhizal (EM) fungi associated with old- and second-growth Douglas-fir stands. Using molecular analyses of rhizomorphs and EM root tips, we characterized 28 unique internal transcribed spacer sequences and considered them proxies for mat-forming EM species. In both stand age classes, one Athelioid species in the genus Piloderma dominated our sample of the mat-forming fungal community. In second-growth stands, the second most frequently encountered mat-forming EM species belonged to the genus Hysterangium. In old-growth stands, several Ramaria species were associated with a frequently encountered mat morphology but no species dominated the community. After using rarefaction analysis to standardize sampling effort, the total species richness did not differ statistically between old- and second-growth habitats. Both an abundance of infrequently encountered species and incomplete sampling of the mat-forming EM community may have limited our ability to detect potential differences in species richness. Several frequently encountered Piloderma species appear to have broad (holarctic) distributions and diverse host associations and their potential importance in forest ecosystems warrants further study.
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| 6. |
- Ek, Hans, et al.
(författare)
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Carbon and nitrogen flow in Silver birch and Norway spruce connected by a common mycorrhizal mycelium
- 1996
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 1432-1890 .- 0940-6360. ; 6:6, s. 465-467
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Tidskriftsartikel (refereegranskat)abstract
- Spruce and birch seedlings were grown together in boxes filled with unsterile pear. Both seedlings were colonized by the ectomycorrhizal fungus Scleroderma citrinum. The two plants thus shared a common external mycelium. N-15-labelled ammonium was supplied exclusively to the fungus, while the birch or the spruce plant was continuously fed with C-13-labelled CO2 for 72 h. The carbon and nitrogen transfer rates were strikingly different for birch and spruce seedlings. The mycorrhizal mycelium received carbohydrates mainly from the birch plant and the nitrogen transfer by the fungus to the plants was largely directed towards the birch. Carbon assimilates were also transferred in both directions between birch and spruce; however, there was no conclusive evidence for a net transfer of carbon between the plants.
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| 7. |
- Eshghi Sahraei, Shadi, et al.
(författare)
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Whole genome analyses based on single, field collected spores of the arbuscular mycorrhizal fungus Funneliformis geosporum
- 2022
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Ingår i: Mycorrhiza. - : Springer. - 0940-6360 .- 1432-1890. ; 32:5-6, s. 361-371
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Tidskriftsartikel (refereegranskat)abstract
- Arbuscular mycorrhizal (AM) fungi are ubiquitous mutualistic symbionts of most terrestrial plants and many complete their lifecycles underground. Whole genome analysis of AM fungi has long been restricted to species and strains that can be maintained under controlled conditions that facilitate collection of biological samples. There is some evidence suggesting that AM fungi can adapt to culture resulting in phenotypic and possibly also genotypic changes in the fungi. In this study, we used field isolated spores of AM fungi and identified them as Funneliformis geosporum based on morphology and phylogenetic analyses. We separately assembled the genomes of two representative spores using DNA sequences of 19 and 22 individually amplified nuclei. The genomes were compared with previously published data from other members of Glomeraceae including two strains of F. mosseae. No significant differences were observed among the species in terms of gene content, while the single nucleotide polymorphism density was higher in the strains of F. geosporum than in the strains of F. mosseae. In this study, we demonstrate that it is possible to sequence and assemble genomes from AM fungal spores sampled in the field, which opens up the possibility to include uncultured AM fungi in phylogenomic and comparative genomic analysis and to study genomic variation in natural populations of these important plant symbionts.
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| 8. |
- Fransson, Petra
(författare)
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Carbon availability affects already large species-specific differences in chemical composition of ectomycorrhizal fungal mycelia in pure culture
- 2023
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Ingår i: Mycorrhiza. - 0940-6360 .- 1432-1890. ; 33, s. 303-319
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Tidskriftsartikel (refereegranskat)abstract
- Although ectomycorrhizal (ECM) contribution to soil organic matter processes receives increased attention, little is known about fundamental differences in chemical composition among species, and how that may be affected by carbon (C) availability. Here, we study how 16 species (incl. 19 isolates) grown in pure culture at three different C:N ratios (10:1, 20:1, and 40:1) vary in chemical structure, using Fourier transform infrared (FTIR) spectroscopy. We hypothesized that C availability impacts directly on chemical composition, expecting increased C availability to lead to more carbohydrates and less proteins in the mycelia. There were strong and significant effects of ECM species (R-2 = 0.873 and P = 0.001) and large species-specific differences in chemical composition. Chemical composition also changed significantly with C availability, and increased C led to more polysaccharides and less proteins for many species, but not all. Understanding how chemical composition change with altered C availability is a first step towards understanding their role in organic matter accumulation and decomposition.
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| 9. |
- Hagerberg, David, et al.
(författare)
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The elemental content in the mycelium of the ectomycorrhizal fungus Piloderma sp during the colonization of hardened wood ash
- 2005
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 1432-1890 .- 0940-6360. ; 15:6, s. 387-392
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Tidskriftsartikel (refereegranskat)abstract
- Piloderma sp., a wood ash-colonizing ectomycorrhizal (EM) fungus, was grown symbiotically with Norway spruce in microcosms which contained granules of hardened wood ash. Mycelium close to the granules was sampled 3 times over a period of 11 weeks and the elemental content was investigated with particle induced X-ray emission. Mycelium from microcosms without wood ash was used as controls. The contents of P and K were similar in mycelium growing close to wood ash granules to those in control mycelium, while the Ca content increased from 23 +/- 21 mg g(-1) in controls to 63 +/- 8 mg g(-1) in mycelium growing close to wood ash granules. The Ca content was also increased in other parts of the mycelium more distant from the wood ash. Piloderma sp. may have a role in the short-term storage of Ca released from wood ash, rather than in releasing and storing P.
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| 10. |
- Hammer, Edith, et al.
(författare)
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Elemental composition of arbuscular mycorrhizal fungi at high salinity.
- 2011
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 1432-1890 .- 0940-6360. ; 21, s. 117-129
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the elemental composition of spores and hyphae of arbuscular mycorrhizal fungi (AMF) collected from two saline sites at the desert border in Tunisia, and of Glomus intraradices grown in vitro with or without addition of NaCl to the medium, by proton-induced X-ray emission. We compared the elemental composition of the field AMF to those of the soil and the associated plants. The spores and hyphae from the saline soils showed strongly elevated levels of Ca, Cl, Mg, Fe, Si, and K compared to their growth environment. In contrast, the spores of both the field-derived AMF and the in vitro grown G. intraradices contained lower or not elevated Na levels compared to their growth environment. This resulted in higher K:Na and Ca:Na ratios in spores than in soil, but lower than in the associated plants for the field AMF. The K:Na and Ca:Na ratios of G. intraradices grown in monoxenic cultures were also in the same range as those of the field AMF and did not change even when those ratios in the growth medium were lowered several orders of magnitude by adding NaCl. These results indicate that AMF can selectively take up elements such as K and Ca, which act as osmotic equivalents while they avoid uptake of toxic Na. This could make them important in the alleviation of salinity stress in their plant hosts.
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