Fungus-Bacteria Interactions in Decomposing Wood: Unravelling Community Effects
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Fungus-bacteria interactions in decomposing wood: unravelling community effects A thesis submitted to Cardiff University for the degree of Doctor of Philosophy By Sarah Rose Johnston, B.Sc (Hons) September 2017 DECLARATION This work has not been submitted in substance for any other degree or award at this or any other university or place of learning, nor is being submitted concurrently in candidature for any degree or other award. Signed ……………………………………………………… (candidate) Date ………………….…………….……… STATEMENT 1 This thesis is being submitted in partial fulfillment of the requirements for the degree of Ph.D. Signed ………………………………………….…………… (candidate) Date …………………………….…………… STATEMENT 2 This thesis is the result of my own independent work/investigation, except where otherwise stated, and the thesis has not been edited by a third party beyond what is permitted by Cardiff University’s Policy on the Use of Third Party Editors by Research Degree Students. Other sources are acknowledged by explicit references. The views expressed are my own. Signed ……………………………………….……….…… (candidate) Date …………………….………………… STATEMENT 3 I hereby give consent for my thesis, if accepted, to be available online in the University’s Open Access repository and for inter-library loan, and for the title and summary to be made available to outside organisations. Signed ……………………………………………..…..….. (candidate) Date ………………………………………… STATEMENT 4: PREVIOUSLY APPROVED BAR ON ACCESS I hereby give consent for my thesis, if accepted, to be available online in the University’s Open Access repository and for inter-library loans after expiry of a bar on access previously approved by the Academic Standards & Quality Committee. Signed ……………………………………………..……… (candidate) Date ………………………………….……… i Blessed be the name of God forever and ever, to whom belong wisdom and might. He changes times and seasons; […] He gives wisdom to the wise and knowledge to those who have understanding; He reveals deep and hidden things; He knows what is in the darkness, and the light dwells with Him. To You, O God of my fathers, I give thanks and praise, For You have given me wisdom and might, and have now made known to me what we asked of You Daniel 2: 20-23 (ESV) ii Acknowledgements Many people have merited a lot of thanks over the course of this PhD: - My supervisors, Prof. Andy Weightman and Prof. Lynne Boddy: Andy for his unstinting patience, good humour and guidance; and Lynne, who started as my ecological hero and has only gone up in my estimation! I couldn’t have wished for a better supervisory team; - The Natural Environment Research Council for studentship NE/L501773/1; - Dr. Jen Hiscox and Dr. Mel Savoury for all-round superheroics in every respect; - Dr. Gordon Webster and Dr. Angharad Williams for guiding me up a steep learning curve into molecular biology; - Aimee Bettridge for being an absolutely first-rate PTY student and for all her hard work; - The fungal ecology group: Don A’Bear, Jade O’Leary, Emma Gilmartin, Marta Misiak, Selin Toledo, Jordon Cuff, Poppy Mynard and Dr. Yu Fukasawa, for many adventures; - The bioinformaticians who so generously shared their time and knowledge: Dr. Kevin Ashelford, Dr. Anna Evans, Dr. Annette Evans and Dr. Daniel Farewell; - Derek Schafer for use of his land on the Usk site in Chapter 4; - Three ladies who quietly kept the wheels turning: Joan Hubbard, Swapna Khandavalli, and Dru Lewis; - Dr. Tano Gutiérrez Cánovas for helping develop my statistical and ecological thinking over many pleasant lunchtime chats; - The rest of the C/6.15 gang, who have shared in much laughter, some mutual commiseration, and a lot of good food: Anneka Bracken, Matt Dray, Katie Dunkley, Rhian Newman, Caitlin Pearson, Marian Pye, Hisham Razi, Amy Schwartz, Willow Smallbone, Rhidian Thomas, Steve Thomas, James Vafidis, Kath Whittey, Fred Windsor and especially my desk-buddy Ifan Jâms; - The folk at the Staff and Postgraduate Christian Fellowship, and everyone who has encouraged and prayed for me; - The little group of dear friends who have reminded me that there is life outside the lab; - My brother Tim for being an excellent field and lab assistant, and ensuring I logged a respectable portfolio in practical musicianship; - Mum and Dad, who in a world of knowledge gave me map, compass and a desire to explore, and who have always been by my side; - And above all, to the God of all wisdom and strength be all the honour and all the glory. iii Statement of contributions Where colleagues and students have assisted with work presented in this thesis, their contributions are explicitly detailed below: Chapter 3: Dr. Anna Evans contributed an R script to query the NCBI database via Primer- BLAST. Chapter 4: Dr. Jen Hiscox and Dr. Mel Savoury collaborated on the field and lab work as part of a complementary study. Casey Morris and Sindy Kaur Reyat assisted with lab work. Chapter 5: Dr. Jen Hiscox and Dr. Mel Savoury collaborated on the field and lab work as part of a complementary study. Tim Johnston, Aimee Bettridge and Marion Moriot assisted with field and lab work. Chapter 6: Aimee Bettridge collaborated on the experimental design and practical work. Dr. Tony Hayes conducted the confocal microscopy. Alex Mullins provided information on strain classification and produced the tree in Fig 6.2. Dr. Daniel Farewell gave invaluable advice in developing a statistical model for the interaction data. iv Table of contents Acknowledgements ............................................................................................................. iii Statement of contributions ................................................................................................. iv Table of contents .................................................................................................................. v Summary ............................................................................................................................. ix List of Tables ........................................................................................................................ x List of Figures ...................................................................................................................... xi List of Publications ............................................................................................................ xiii Chapter 1. General Introduction ..................................................................................... 1 1.1 The decomposing wood environment ........................................................................ 1 1.2 Wood-decay fungi ...................................................................................................... 1 1.3 The role of bacteria in the dead-wood environment ................................................. 3 1.4 Thesis aims ................................................................................................................. 4 Chapter 2. Bacteria in decomposing wood and their interactions with wood-decay fungi . 6 2.1 Abstract .......................................................................................................................... 6 2.2. Introduction ................................................................................................................... 7 2.3. Diversity of bacterial communities in wood .................................................................. 7 2.4. Bacterial colonisation of wood .................................................................................... 12 2.4.1. Edaphic and atmospheric sources of bacteria ..................................................... 13 2.4.2 Bacterial endophytes............................................................................................. 13 2.4.3 Bacteria co-colonisation with other organisms .................................................... 13 2.5. Wetwood ..................................................................................................................... 14 2.6. Bacterial metabolism in wood .................................................................................... 14 2.6.1 Bacterial nitrogen fixation in wood ....................................................................... 14 2.6.2 Bacterial wood decomposition .............................................................................. 16 2.7. Bacterial-fungal community interactions ................................................................... 18 2.7.1 Community competition and co-operation ........................................................... 18 2.7.2 Bacterial endosymbiosis and intimate hyphal associations .................................. 20 2.7.3 Mycophagy and predation .................................................................................... 21 2.8. Conclusions and future perspectives ........................................................................... 22 Chapter 3. Bacterial qPCR primers co-amplify fungi ....................................................... 25 3.1 Abstract ........................................................................................................................ 25 3.2 Introduction .................................................................................................................. 26 3.3 Materials and methods ................................................................................................ 26 3.4 Results and Discussion ................................................................................................