Aberdeen Mycorrhiza Research Group

We have 4 PhD projects (listed below) available and are keen to hear from enthusiastic graduates of biology, mycology, environmental and soil science etc.

Deadline for applications: Decemeber 1st 2008.

1) Chewing up the wood-wide web: how do soil animals disrupt carbon and nutrient transfers through fungal networks?

In temperate and boreal forests, the dominant group of soil microorganisms are ectomycorrhizal (EM) fungi that form extensive mycelial networks (the so-called “wood-wide web”). The biomass of EM fungi and the amounts of carbon (C) allocated to their mycelium can account for a substantial percentage of current plant assimilate. In nature, EM fungi coexist with diverse communities of fungivorous soil organisms (e.g. enchytraeid worms, Collembola and mites) that have the potential to damage fungal mycelial networks and below ground C fluxes. In addition, the specificity seen in some fungivorous invertebrates suggests they have the potential to be a strong selective force in shaping fungal diversity, but that the diversity of the fungivores themselves may be an important driver of these impacts. This PhD will test the hypotheses that 1) soil mesofauna disrupt C fluxes between plants and EM fungi, 2) soil mesofauna shape EM fungal community composition, and 3) the extent of disruption to the functional diversity of EM fungi is dependent on the composition of the fungivore communities. This will be achieved using a combination of laboratory and field experiments and application of state-of-the-art molecular and stable isotope tracers.

Supervisor(s): Dr David Johnson, Dr Andy Taylor

Funded by:

UK research council studentship

Eligibility and application:

Fees will be paid at UK/EU rates only. Candidates should hold, or expect to obtain, a First or Upper Second Class Honours degree or a Masters degree or an equivalent qualification

Commences October 2009

To apply send an application form, downloadable from http://www.abdn.ac.uk/sras/postgraduate/pgapp.doc along with a covering letter and an up-to-date C.V. (no longer than 2 sides of A4) to Dr David Johnson (d.johnson@abdn.ac.uk)

2) Extinctions of symbiotic fungi in alpine and subarctic ecosystems

Scottish alpine and subarctic communities contain very rare plant species that are entirely dependent upon symbiotic mycorrhizal fungi, many of which are found nowhere else in the UK. This obligate association enables both symbionts to survive and flourish in conditions that are typically very nutrient poor and climatically harsh. Recent research has shown that contrary to expectation, many of these plant communities are undergoing rapid species changes. The suggested casual factors are elevated nitrogen deposition and climatic shifts. We know that mycorrhizal fungi are particularly sensitive to environmental perturbations such as these. This project will investigate the hypothesis that the loss of mycorrhizal fungi specifically adapted to alpine and subarctic conditions is an important factor in driving the observed shifts in plant community structure. The project will combine field work in some of the remotest areas in Scotland with lab based molecular analyses. Field data will be used to select fungi and plant hosts for testing benefits of different host/fungus interactions. The project will provide unique information on Scottish alpine plant and fungal communities, which will be used for developing conservation strategies for these unique and fragile systems. Training will be given in experimental design, fungal taxonomy and molecular ecology.

Supervisor(s): Dr Andy Taylor, Prof Ian Alexander

Funded by:

UK research council studentship

Eligibility and application:

Fees will be paid at UK/EU rates only. Candidates should hold, or expect to obtain, a First or Upper Second Class Honours degree or a Masters degree or an equivalent qualification

Commences October 2009

To apply send an application form, downloadable from http://www.abdn.ac.uk/sras/word_docs/pgapp.doc along with a covering letter and an up-to-date C.V. (no longer than 2 sides of A4) to Dr Andy Taylor (a.taylor@macaulay.ac.uk)

3) Nitrate assimilatory gene evolution in mycorrhizal fungi

The great majority of terrestrial plant species rely upon symbiotic mycorrhizal fungi associated with their roots for nutrient mobilisation and uptake. We recently demonstrated that, with two exceptions, the major clades of basidiomycete fungi capable of forming ectomycorrhizas possess functional nitrate reductase (NAR1) genes. The two exceptions are members of the family Russulaceae and the genus Amanita. No NAR1 genes could be recovered from these groups, but southern blots detected homologues to functional NAR1 genes. Isolates from these groups did, however, show growth on nitrate, suggesting that they posses an alternative but as yet unidentified biochemical pathway for nitrate assimilation. In addition, these two groups of fungi appear to posses a unique morphology when in association with the host plant that may allow uptake and transfer of nitrate directly to the host cells, thereby avoiding the considerable cost of nitrate assimilation. Such a pathway could result in a selection against the retention of the nitrate assimilation genes. This project will examine the evolution of the nitrate assimilation genes in mycorrhizal fungi focusing on the potential loss of function in relation to morphological development. Training will be given in the molecular analysis of fungal genes and ecology of mycorrhizal fungi.

Supervisor(s): Dr Andy Taylor, Prof Ian Alexander

Funded by:

UK research council studentship

Eligibility and application:

4) Community assembly rules for ectomycorrhizal fungi

Most forest trees support a species-rich community of ectomycorrhizal fungi, which are essential for the survival and growth of the tree. But what regulates the composition of the community of fungi which develop in any given situation? We know that some fungi are generalists, colonising many hosts, while some are specialists, and show host preference. We also know that soil factors (eg N status) influence community composition. We suspect that some fungi may be more ‘competitive’ than others. However, we don’t have a general set of rules which would allow us to predict, in a given situation, and with a known set of fungi present, which fungi will colonise, and what their relative abundances on the root system will be. We don’t even know whether the structure of the ectomycorrhizal fungal community is determined primarily by the tree, or by interactions between the fungi! In this project we will challenge seedlings of different tree species with single and mixed fungal inocula, while independently manipulating tree nutrient status, photosynthetic rate, soil nutrient status, etc. in an attempt to understand the rules governing fungal community assembly.

Training will be given in experimental design, fungal taxonomy, fungal molecular ecology etc.

Supervisor(s): Prof Ian Alexander and Dr Andy Taylor

Funded by:

UK research council studentship

Eligibility and application:

We are always keen to hear from prospective students, post-docs and independent research fellow.

Please email Dr David Johnson (D.Johnson@abdn.ac.uk) or Prof. Ian Alexander (I.Alexander@abdn.ac.uk) in the first instance.