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- Harder, Christoffer Bugge, et al.
(författare)
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Mycena species can be opportunist-generalist plant root invaders
- 2023
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Ingår i: Environmental Microbiology. - 1462-2912. ; 25:10, s. 1875-1893
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Tidskriftsartikel (refereegranskat)abstract
- Traditional strict separation of fungi into ecological niches as mutualist, parasite or saprotroph is increasingly called into question. Sequences of assumed saprotrophs have been amplified from plant root interiors, and several saprotrophic genera can invade and interact with host plants in laboratory growth experiments. However, it is uncertain if root invasion by saprotrophic fungi is a widespread phenomenon and if laboratory interactions mirror field conditions. Here, we focused on the widespread and speciose saprotrophic genus Mycena and performed (1) a systematic survey of their occurrences (in ITS1/ITS2 datasets) in mycorrhizal roots of 10 plant species, and (2) an analysis of natural abundances of 13C/15N stable isotope signatures of Mycena basidiocarps from five field locations to examine their trophic status. We found that Mycena was the only saprotrophic genus consistently found in 9 out of 10 plant host roots, with no indication that the host roots were senescent or otherwise vulnerable. Furthermore, Mycena basidiocarps displayed isotopic signatures consistent with published 13C/15N profiles of both saprotrophic and mutualistic lifestyles, supporting earlier laboratory-based studies. We argue that Mycena are widespread latent invaders of healthy plant roots and that Mycena species may form a spectrum of interactions besides saprotrophy also in the field.
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| 2. |
- Kashi, N. Niloufar, et al.
(författare)
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Nutrients Alter Methane Production and Oxidation in a Thawing Permafrost Mire
- 2023
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Ingår i: Ecosystems. - : Springer. - 1432-9840 .- 1435-0629. ; 26, s. 302-317
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Tidskriftsartikel (refereegranskat)abstract
- Permafrost thaw releases nutrients and metals from previously frozen soils and these nutrients may affect important biogeochemical processes including methane (CH4) production and oxidation. Here we assessed how concentrations of nutrients, solutes, and metals varied across four plant communities undergoing permafrost thaw and if these geochemical characteristics affected rates of CH4 production and oxidation. We tested nutrient limitation in CH4 production and oxidation by experimentally adding nitrogen (N), phosphorus (P) and a permafrost leachate to peat across these four plant communities. The upper 20 cm of permafrost contained 715 ± 298 mg m−2 of extractable inorganic N and 20 ± 6 mg m−2 of resin-extractable phosphorus (Presin), for a N:P ratio of 36:1. These low amounts of Presin coincide with high acid-digestible aluminum (Al), iron (Fe), and P concentrations in the permafrost soil and suggest that P may accumulate via sorption and constrain easily available forms of P for plants and microbes. Permafrost leachate additions decreased potential CH4 production rates up to 80% and decreased CH4 oxidation rates by 66%, likely due to inhibitory effects of N in the permafrost. In contrast, organic and inorganic P additions increased CH4 oxidation rates up to 36% in the tall graminoid fen, a community where phosphate availability was low and CH4 production was high. Our results suggest that (1) inorganic N is available immediately from permafrost thaw, while (2) P availability is controlled by sorption properties, and (3) plant community, nutrient stoichiometry, and metal availability modulate how permafrost thaw affects CH4 production and oxidation.
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