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The effect of beneficial microbes on plant fitness and microbiome – an integrated approach
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Sergaki, Chrysi (2019) The effect of beneficial microbes on plant fitness and microbiome – an integrated approach. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3492756~S15
Abstract
The plant root microbiota, consisting of diverse microbial communities within and around the plant roots, can significantly influence plant development and stress tolerance. The goal of this thesis was to analyse the microbe-microbe and plantmicrobe interactions in the root. For this purpose, Serendipita indica, a mutualistic fungal root endophyte, able to improve plant performance and disease resistance in host plants, was studied. Strategies of the fungus to establish colonisation within the plant were studied by investigating the effect of putative S. indica effector proteins on the plant auxin signalling pathway. Single S. indica effectors were found to alter the expression of auxin-related genes, with consequent effects on plant growth, indicating a potential competitive advantage of S. indica gained through effectors against other microbes. Furthermore, by analyzing the effect of two beneficial fungal endophytes, S. indica and Colletotrichum tofieldiae on the rhizobiome composition of Arabidopsis thaliana, inoculated individually on plant roots, I aimed to reveal plant- and/or microbe-derived patterns that are involved in shaping the root microbiome. Using a gnotobiotic system and a synthetic bacterial community, I demonstrated the persistence of the bacterial community in the plant root, as well as the transition of C. tofieldiae to a potentially pathogenic lifestyle hereby affecting plants’ survival. To further test these patterns in a natural environment, a bacterial taxon commonly utilized in agriculture, Rhizobia, was used as a mutualist root symbiont of the legume Medicago truncatula. Rhizobia strains were tested for their ability to stimulate plant growth and nutrient supply as well as their competitiveness in representative UK soil types and their different natural microbiomes. Sinorhizobium meliloti 1022 was found to enhance plant growth and nitrogen acquisition in all soil types, altering the bacterial community structure and composition of the root endosphere, while the fungal community structure and composition was driven only by the soil characteristics. Overall, this work contributes towards elucidating the stability of beneficial plant-microbe interactions in natural communities and in different environments. The long-term aim of such study is to integrate molecular and environmental factors to generate customized beneficial microbiomes that can be applied to sustainably support crop production.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QK Botany Q Science > QR Microbiology |
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Library of Congress Subject Headings (LCSH): | Plant-microbe relationships, Roots (Botany), Endophytic fungi | ||||
Official Date: | April 2019 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | School of Life Sciences | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Schäfer, Patrick | ||||
Format of File: | |||||
Extent: | ii, iv, viii, 185 leaves : illustrations, charts | ||||
Language: | eng |
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