Graduate Theses, Dissertations, and Problem Reports 2019 Elucidating disease dynamics in the biocontrol of Ailanthus altissima while confirming the host specificity of theascular v wilt pathogen Verticillium nonalfalfae Kristen L. Wickert [email protected] Follow this and additional works at: https://researchrepository.wvu.edu/etd Part of the Other Forestry and Forest Sciences Commons Recommended Citation Wickert, Kristen L., "Elucidating disease dynamics in the biocontrol of Ailanthus altissima while confirming the host specificity of the vascular wilt pathogen Verticillium nonalfalfae" (2019). Graduate Theses, Dissertations, and Problem Reports. 3854. https://researchrepository.wvu.edu/etd/3854 This Dissertation is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Dissertation has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. Elucidating disease dynamics in the biocontrol of Ailanthus altissima while confirming the host specificity of the vascular wilt pathogen Verticillium nonalfalfae Kristen L. Wickert Dissertation submitted to the Davis College of Agriculture, Natural Resources and Design at West Virginia University in partial fulfillment of the requirements for the degree of PhD in Plant Pathology Matthew T. Kasson, Ph.D., Chair Ember Morrissey, Ph.D. Daniel G. Panaccione, Ph.D. Scott Salom, Ph.D. Donald Davis, Ph. D. Division of Plant and Soil Sciences Morgantown, West Virginia 2019 Keywords: Verticillium nonalfalfae, tree-of-heaven, biocontrol, Ailanthus Copyright 2019 Kristen Wickert ABSTRACT Elucidating disease dynamics in the biocontrol of Ailanthus altissima while confirming the host specificity of the vascular wilt pathogen Verticillium nonalfalfae Kristen L. Wickert Ailanthus altissima is a highly invasive exotic tree species entrenched throughout the United States. Since the discovery of a vascular wilt disease of Ailanthus in 2002, caused by the fungus Verticillium nonalfalfae, many studies are investigating its potential as a biocontrol focusing on efficacy, host specificity and disease transmission. This study addresses: the reproductive potential of Ailanthus; if V. dahliae alters Verticillium wilt progression; if hardiness zones influence the individual contributions of two Verticillium spp.; can a unique habitat affect biocontrol efficacy; and can the fungal proteome of V. nonalfalfae allow us to explain differences in host specificity? Cumulative seed production in individual Ailanthus reached ca. 10 and 52 million seeds over a 40-year and 100-year period, respectively. Forested sites inoculated with both Ailanthus pathogenic species of Verticillium experienced the same mortality rates as sites with just V. nonalfalfae alone. When comparing mortality caused by Verticillium wilt in three hardiness zones, it was found that there was no difference in disease progression. Ailanthus established on previous strip mine sites displayed resistance to the pathogen. Tree ring observations and X-ray fluorescence mineral assays indicated high concentrations of iron which inhibited Verticillium infection. Isolates of Verticillium species and strains from different plant hosts displayed differences in pathogenicity to Ailanthus seedlings and had distinct proteomes from each other when analyzed with MALDI-TOF-MS, indicating Verticillium isolates from different sources respond to their host environment differently. Dedication This dissertation is dedicated to my mother and my close friends. iii Acknowledgements I would like to express my intense gratitude to my committee for their advice, knowledge, and support through my efforts to complete my PhD. Dr. Daniel Panaccione, Dr. Ember Morrissey, Dr. Scott Salom, Dr. Don Davis and Dr. Matthew Kasson have all been valuable academic mentors to my future and have taught me many life lessons. Thank you to Amy Metheny and Cameron Stauder, along with his wife Laura. Chansotheary Dang and Jeth Walkup have been some of the best office mates a graduate student could ask for. iv Table of Contents Abstract .......................................................................................................................................... ii Dedication ..................................................................................................................................... iii Acknowledgments ........................................................................................................................ iv List of Tables .............................................................................................................................. viii List of Figures .................................................................................................................................x Chapter 1. Literature Review ......................................................................................................1 Tree-of-heaven (Ailanthus altissima) ..............................................................................................1 Verticillium nonalfalfae ...................................................................................................................5 Taxonomy and Phylogenetics of the genus Verticillium .................................................................6 History of Verticillium wilt caused by V. nonalfalfae and V. dahliae .............................................8 Examples of Successful Biocontrol efforts ....................................................................................11 References ......................................................................................................................................17 Chapter 2. Seed Production, Viability and Reproductive Limits of the Invasive Ailanthus altissima (tree-of-heaven) within Invaded Environments Abstract ..........................................................................................................................................23 Introduction ....................................................................................................................................24 Materials and Methods ...................................................................................................................26 Statistical Analyses ........................................................................................................................29 Results ............................................................................................................................................29 Seed Production .............................................................................................................................29 Germination Studies to Assess Seed Viability Based on Seed and Tree Age ...............................32 Tetrazolium Assay to Evaluate Seed Viability ..............................................................................32 Discussion ......................................................................................................................................33 Conclusions ....................................................................................................................................36 Acknowledgements ........................................................................................................................37 Tables .............................................................................................................................................38 Figures............................................................................................................................................39 References ......................................................................................................................................42 v Chapter 3. Disease progression of Verticillium nonalfalfae and V. dahliae, causal agents of Verticillium wilt of Ailanthus, in different hardiness zones of Pennsylvania, USA Abstract ..........................................................................................................................................45 Introduction ....................................................................................................................................46 Materials and Methods ...................................................................................................................50 Statistical Analyses ........................................................................................................................57 Results ............................................................................................................................................58 Viability of V. nonalfalfae and V. dahliae in Long Term Storage .................................................58 Efficacy of V. nonalfalfae-inoculated soil and rye grain on Ailanthus seedlings in a controlled environment ...................................................................................................................................59