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Interactions between ectomycorrhizal associations and bacteria

Marupakula, Srisailam (2016). Interactions between ectomycorrhizal associations and bacteria. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2016:42
ISBN 978-91-576-8586-5
eISBN 978-91-576-8587-2
[Doctoral thesis]

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Abstract

Boreal forest podzol soils have vertically stratified horizons with different physico-chemical characteristics and high microbial diversity. Ectomycorrhizal fungi play key roles in accessing nutrients from both organic and mineral substrates. The role of associated bacteria in these processes is still poorly understood. The aim of the studies described in this thesis was to improve understanding of the distribution, diversity and community structure of fungi and bacteria on roots and in soil and their responses to environmental perturbations such as N-fertilisation.

In two microcosm studies a single-root tip microbiome method was used to sample bacteria associated with different ectomycorrhizal roots at defined time-points, using high throughput sequencing of both fungi and bacteria The first study revealed highly dynamic patterns of assembly of bacterial communities associated with ectomycorrhizal roots at different time points in organic soil. Bacterial community structure differed between roots colonised by different species of ectomycorrhizal fungi from different genera. The second study extended these results to include both organic and mineral horizons, demonstrating significant differences between fungal and bacterial communities colonising soil from different horizons. Responses of both fungi and bacteria to short-term N additions were context dependent, influenced by both soil horizon and the dominant ectomycorrhizal fungi colonising the roots. Bacterial communities associated with roots colonised by pairs of closely related fungal species within the same fungal genera were also shown to be statistically distinct.

Field studies of fungi and bacteria in a forest fertilised with 150 kg N ha⁻¹ 15 months previously, revealed 1017 unique fungal OTUs, (877 in the soil, 652 in the roots). N increased fungal diversity slightly in the O horizon soil but decreased it in the roots, particularly in the B horizon. Fungal community structure varied significantly between horizons and within each soil horizon the community structure of fungi colonising ectomycorrhizal roots was significantly different from that associated with the soil, suggesting that analyses of both soil and roots are necessary for accurate monitoring of environmental perturbations. 10925 unique bacterial OTUs were distinguished in total (8560 in the soil, 5512 in the roots). Bacteria displayed similar trends to the fungi but were less strongly influenced by N. These studies pave the way for more detailed functional studies of specific combinations of fungi and bacteria.

Authors/Creators:Marupakula, Srisailam
Title:Interactions between ectomycorrhizal associations and bacteria
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :3 May 2016
Depositing date:4 May 2016
Volume:2016:42
Number of Pages:90
Papers/manuscripts:
NumberReferences
IMarupakula S, Mahmood S, Finlay RD. 2015. Analysis of single root tip microbiomes suggests that distinctive bacterial communities are selected by Pinus sylvestris roots colonised by different ectomycorrhizal fungi. Environmental Microbiology (In Press). doi: 10.1111/1462-2920.
IIMarupakula S, Mahmood S, Jernberg J, Nallanchakravarthula S, Fahad Z, Finlay RD. 2015. Bacterial microbiomes of Pinus sylvestris roots colonised by different ectomycorrhizal fungi: effects of soil horizon and N addition. (manuscript)
IIIMarupakula S, Mahmood S, Santos J, Jacobson S, Högbom L, Finlay RD. Analysis of fungal communities colonising mycorrhizal tree roots and soil in a nitrogen-fertilised boreal forest podzol. (manuscript).
IVMarupakula S, Mahmood S, Finlay RD. Analysis of bacterial communities colonising mycorrhizal tree roots and soil in a nitrogenfertilised boreal forest podzol. (manuscript).
Place of Publication:Uppsala
Publisher:Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8586-5
ISBN for electronic version:978-91-576-8587-2
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K01 Forestry - General aspects
P Natural resources > P34 Soil biology
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Soil Science
Agrovoc terms:ectomycorrhizae, boreal forests, forest soils, podzols, soil fungi, pinus sylvestris, roots, bacteria, nitrogen, fertilizer application, rhizosphere, plant soil relations
Keywords:Ectomycorrhizal fungi, Bacteria, Microbiome, Horizons, Nitrogen fertilisation, High throughput sequencing, Root tips
URN:NBN:urn:nbn:se:slu:epsilon-e-3422
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-3422
ID Code:13343
Faculty:S - Faculty of Forest Sciences
Department:(NL, NJ) > Dept. of Forest Mycology and Plant Pathology
(S) > Dept. of Forest Mycology and Plant Pathology
External funders:FORMAS
Deposited By: Mr Srisailam Marupakula
Deposited On:05 May 2016 05:09
Metadata Last Modified:09 May 2016 05:58
Project info:
Name:Swedish University of Agricultural Sciences (SLU)
Acronym:European Commission. Grant Number: FP7-264465

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