Strain identity of the ectomycorrhizal fungus Laccaria bicolor is more important than richness in regulating plant and fungal performance under nutrient rich conditions

This work was funded by the Natural Environment Research Council (NE/I014527/1).Peer reviewedPublisher PD

Tripartite symbioses regulate plant–soil feedback in alder

ACKNOWLEDGEMENTS We thank the National Trust for Scotland for access to the Crathes Estate. This work was funded by the Natural Environment Research Council (ref NE/M015653/1) and a Ramon Areces Fellowship to A.A. D.J. receives partial funding from the N8 AgriFood programme. We thank Filipa Cox for a critical read of the manuscript.Peer reviewedPublisher PD

Karhunen-Loeve eigenvalue problems in cosmology: how should we tackle large data sets?

Since cosmology is no longer "the data-starved science", the problem of how to best analyze large data sets has recently received considerable attention, and Karhunen-Loeve eigenvalue methods have been applied to both galaxy redshift surveys and Cosmic Microwave Background (CMB) maps. We present a comprehensive discussion of methods for estimating cosmological parameters from large data sets, which includes the previously published techniques as special cases. We show that both the problem of estimating several parameters jointly and the problem of not knowing the parameters a priori can be readily solved by adding an extra singular value decomposition step. It has recently been argued that the information content in a sky map from a next generation CMB satellite is sufficient to measure key cosmological parameters (h, Omega, Lambda, etc) to an accuracy of a few percent or better - in principle. In practice, the data set is so large that both a brute force likelihood analysis and a direct expansion in signal-to-noise eigenmodes will be computationally unfeasible. We argue that it is likely that a Karhunen-Loeve approach can nonetheless measure the parameters with close to maximal accuracy, if preceded by an appropriate form of quadratic "pre-compression". We also discuss practical issues regarding parameter estimation from present and future galaxy redshift surveys, and illustrate this with a generalized eigenmode analysis of the IRAS 1.2 Jy survey optimized for measuring beta=Omega^{0.6}/b using redshift space distortions.Comment: 15 pages, with 5 figures included. Substantially expanded with worked COBE examples for e.g. the multiparameter case. Available from http://www.sns.ias.edu/~max/karhunen.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/karhunen.html (faster from Europe) or from [email protected]

Location, but not defensive genotype, determines ectomycorrhizal community composition in Scots pine (<i>Pinus sylvestris</i> L.) seedlings

1. For successful colonization of host roots, ectomycorrhizal (EM) fungi must overcome host defense systems, and defensive phenotypes have previously been shown to affect the community composition of EM fungi associated with hosts. Secondary metabolites, such as terpenes, form a core part of these defense systems, but it is not yet understood whether variation in these constitutive defenses can result in variation in the colonization of hosts by specific fungal species. 2. We planted seedlings from twelve maternal families of Scots pine (Pinus sylvestris) of known terpene genotype reciprocally in the field in each of six sites. After 3 months, we characterized the mycorrhizal fungal community of each seedling using a combination of morphological categorization and molecular barcoding, and assessed the terpene chemodiversity for a subset of the seedlings. We examined whether parental genotype or terpene chemodiversity affected the diversity or composition of a seedling's mycorrhizal community. 3. While we found that terpene chemodiversity was highly heritable, we found no evidence that parental defensive genotype or a seedling's terpene chemodiversity affected associations with EM fungi. Instead, we found that the location of seedlings, both within and among sites, was the only determinant of the diversity and makeup of EM communities. 4. These results show that while EM community composition varies within Scotland at both large and small scales, variation in constitutive defensive compounds does not determine the EM communities of closely cohabiting pine seedlings. Patchy distributions of EM fungi at small scales may render any genetic variation in associations with different species unrealizable in field conditions. The case for selection on traits mediating associations with specific fungal species may thus be overstated, at least in seedlings

In vitro evidence of root colonization suggests ecological versatility in the genus Mycena

Acknowledgements: The European commission is acknowledged for a MSCA grant to C.B.H (grant no. 658849), the University of Oslo for further funding of the project, and the Swedish University of Agricultural Sciences for hosting parts of the experiments. C.B.H was funded by an internationalisation grant from the Carlsberg Research Grant Foundation at the time of writing (grant no. CF18-0809). We would like to thank Jerome Guerrand for aid in in vitro laboratory techniques, the Norwegian Forest Seed Center for provision of seeds, Hedda Weitz and Tatiana A. Semenova-Nelson and Taina Pennanen for provision of fungal cultures. We would like to thank Marc-André Selosse, Peter Kennedy and four anonymous referees for valuable comments to an earlier version of this manuscript.Peer reviewedPublisher PD

The UNITE database for molecular identification of fungi : handling dark taxa and parallel taxonomic classifications

Alfred P. Sloan Foundation [G-2015-14062]; Swedish Research Council of Environment, Agricultural Sciences, and Spatial Planning [FORMAS, 215-2011-498]; European Regional Development Fund (Centre of Excellence EcolChange) [TK131]; Estonian Research Council [IUT20-30]. Funding for open access charge: Swedish Research Council of Environment, Agricultural Sciences and Spatial Planning.Peer reviewedPublisher PD

The consistency relation in braneworld inflation

The braneworld cosmology, in which our universe is imbedded as a hypersurface in a higher dimensional bulk, has the peculiar property that the inflationary consistency relation derived in a four-dimensional cosmology persists. This consistency condition relates the ratio of tensor and scalar perturbation amplitudes to the tensor spectral index produced during an epoch of slow-roll scalar field inflation. We attempt to clarify this surprising degeneracy. Our argument involves calculating the power spectrum of scalar field fluctuations around geometries perturbed away from the exact de Sitter case. This calculation is expected to be valid for perturbations which would not cause a late-time acceleration of the universe. We use these results to argue that the emergence of the same consistency relation in the braneworld can be connected with a specific property, that five-dimensional observables smoothly approach their four-dimensional counterparts as one takes the brane to infinite tension. We exhibit an explicit example where this does not occur, and in which a consistency relation does not persist.Comment: 14 pages, Latex, uses revtex 4; submitted to Phys. Rev.

Mycena species can be opportunist-generalist plant root invaders

ACKNOWLEDGEMENTS We thank Karl-Henrik Larsson and Arne Aronsen for provisions of specimens from the Natural History Museum of Oslo and help with the identification of field specimens from Svalbard. We further thank Cecilie Mathiesen and Mikayla Jacobs for technical assistance in the laboratory, Brendan J. Furneaux for valuable input to the R script, and the curators of H, TUR, and OULU. The Mycena ITS sequences originating from the specimens deposited in H, TUR, and OULU were produced as part of the Finnish Barcode of Life Project (FinBOL) funded by the Ministry of Environment, Finland (YM23/5512/2013), Otto A Malm's Donationsfond, and the Kone Foundation. We thank the European Commission (grant no. 658849) and the Carlsberg Foundation (grant no. CF18-0809) for grants to C.B. Harder that made this research possible. C.B. Harder was financed by a grant from the Danish Independent Research Fund DFF/FNU 2032-00064B (SapMyc) at the time of writing. Research Funding Carlsbergfondet. Grant Number: CF18-0809 Danish Independent Research Fund. Grant Number: 2032-00064B European Commission. Grant Number: 658849 Ministry of Environment, Finland. Grant Number: YM23/5512/2013Peer reviewedPublisher PD