Phenotypic Diversity in the Wheat Wild Relative Aegilops Longissima
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PHENOTYPIC DIVERSITY IN THE WHEAT WILD RELATIVE AEGILOPS LONGISSIMA A THESIS SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY SHUYI HUANG IN PARTIAL FULFILLMENT OF REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE Adviser: Brian J. Steffenson November 2016 © Shuyi Huang 2016 Acknowledgements I would like to express my sincere gratitude and appreciation to my mentor and major advisor, Dr. Brian Steffenson, for all his guidance, support, patience, and encouragement throughout my study at University of Minnesota. I am grateful to Dr. Steffenson for sharing his knowledge of plant pathology, providing insight into this thesis, and leading me to the fascinating and meaningful world of crop improvement and research. My grateful appreciation also goes to Dr. James Kolmer and Dr. James Anderson, who served on my thesis committee. Dr. Kolmer and Dr. Anderson provided their helpful advice and guidance during my graduate work and a critical review of my thesis. From all of these individuals, I have gained the knowledge and experience to be a good and independent scientist. I extend my gratitude to Dr. Xianming Chen (USDA-ARS) at Pullman, Washington for providing the materials and guidance for working with the stripe rust pathogen. Dr. Hanan Sela and Dr. Eitan Millet of the Institute for Cereal Crops Improvement at Tel Aviv University (ICCI-TAU) generously shared their extensive knowledge about Aegilops longissima with me. I thank the ICCI-TAU in Tel Aviv, Israel and Leibniz-Institute für Pflanzengenetik und Kulturpflanzenforschung (IPK) in Gatersleben Germany for providing the Ae. longissima germplasm that made this project possible. I also extend my sincere appreciation to the entire Steffenson project for providing me with a friendly and enjoyable environment in which to conduct my studies. I thank Matthew Martin and Tamas Szinyei for their help and support in the laboratory and greenhouse, and to the students Kathleen Ring, Angela Tomlinson, George Saparashvili, Giorgi Beruashvili, Nathalia Salgado Silva, and Evandro Henrique Figueiredo Moura Da Silva who assisted me in my work. My appreciation also goes to Austin Case, Jeness Scott, Pablo Olivera Firpo, Jamie Simmons, Matthew Haas, and Cole i Welchlin for their inspiring and helpful suggestions. Finally, I would like to thank all of the faculty, staff, and graduate students in the Department of Plant Pathology who provided help, encouragement, and friendship during my time at the University of Minnesota. I express my deep love and gratitude to my family for walking with me through this journey. I greatly appreciate my father Zili Zhou and my mother Qunying Wang for their financial support, encouragement, and understanding during my studies far from home. I am also grateful to my sister Minyi Huang, my brother Zexian Huang, and all of my friends for their support. A debt of gratitude is owed to Yu Wang and Kathryn Stinebaugh from the Department of Statistics and U-Spatial, who provided help and guidance on data analysis. ii Dedication This thesis is dedicated to my father (Zili Zhou) and mother (Qunying Wang) for their love and encouragement. iii Abstract Aegilops longissima is an annual grass species that is native to the eastern Mediterranean Basin and is recognized as a potential source of genetic diversity for cultivated wheat improvement. The primary objectives of this research were to assemble a diverse collection of Ae. longissima and characterize it for agro-morphological traits and resistance to the diseases of stem rust (caused by P. graminis f. sp . tritici ), leaf rust (P. triticina ) and stripe rust ( P. striiformis f. sp. tritici ). A collection of 433 accessions of the species, mostly from Israel, was assembled for this study. Evaluation results indicate that Ae. longissima is very diverse for many agro-morphological traits, especially leaf area. With respect to stem rust resistance, 18% and 80% of accessions were resistant to P. graminis f. sp . tritici pathotypes TTTTF and TTKSK, respectively. The percentage of accessions exhibiting resistance to pathotypes of the leaf rust and stripe rust pathogens ranged from 50 to 62%. Ten accessions were resistant to all races of the three pathogens investigated in this study. The great advances made recently in genomics opens up the possibility for exploiting the allelic diversity of Ae. longissima for cultivated wheat improvement. iv Table of Contents Acknowledgements………………...……………………..………..…..…………………i Dedication…………………………………………………………………….………….iii Abstract………………...……………………..…………..………………………..…….iv Table of Contents………………...………………..…………..……………………..….v List of Tables………………...……………………..…………..……………………….vii List of Figures……………………………………..……………..………………………ix Chapter 1: Genetics, Taxonomy, and Ecology of Aegilops longissima and Establishment of a Diversity Collection for the Species……………………………….1 1. Introduction……………………………………………………………………………..2 2. Name and taxonomy……………………………...…………………………..………...6 3. Morphology and life cycle……………………………………………………………...7 4. Ecology and geographic distribution…………………………………………………...9 5. Establishment of a diversity collection of Aegilops longissima ………………………11 Chapter 2: Phenotypic Diversity for Agro-morphological Traits in the Wheat Wild Relative Aegilops longissima ……………………………………………………………32 1. Introduction……………………………………………………………………………33 2. Materials and methods………………………………………………………………...35 2.1. Plant materials…………………………………………………....………………….35 2.2. Plant growth conditions…...………………………………………………………...36 2.3. Agro-morphological traits assessment………………………………….…………...37 2.4. Data analysis………………………………………………………………………...38 v 3. Results…………………………………………………………………………………41 4 Discussion……………………………………………………………………………...44 Chapter 3: Diversity of Aegilops longissima for Resistance to Wheat Rust Pathogens………………………………………………………………………………..60 1. Introduction……………………………………………….…………………………...61 2. Materials and methods………………………………………………………………...67 2.1. Plant materials…………………………………………………………………….....67 2.2. Plant growth conditions……………………………………………………………..68 2.3. Pathogen isolates…………………………………………………………………….69 2.3.1. Puccinia graminis f. sp . tritici …………………………………………………….69 2.3.2. Puccinia triticina ………………………………………………………………….70 2.3.3. Puccinia striiformis f. sp . tritici …………………………....……………………...70 2.4. Inoculation protocols and infection/incubation period……………………………...71 2.5. Disease assessment………………………………………………………...………..72 2.6. Data analysis………………………………………………………………………...73 3. Results………………………………………………………………………………....76 3.1. Resistance to Puccinia graminis f. sp. tritici ……………………………………......76 3.2. Resistance to Puccinia triticina ………………………………………………...…...77 3.3. Resistance to Puccinia striiformis f. sp. tritici ………………………………….…...77 3.4. Spatial autocorrelation analysis based on Global Moran’s I……………...………...79 3.5. Simple linear regression analysis of rust phenotypes and climate data…………......79 4. Discussion……………………………………………………………………………..80 Bibliography…………………………………………………………………………...106 Appendix…………………………………..…………………………………………...114 vi List of Tables Chapter 1 Table 1.1. List of section Sitopsis species of the genus Aegilops and their common names and genome designations………………………………………………………………...15 Table 1.2. Summary of agronomic traits identified in section Sitopsis species of the genus Aegilops …………………………………………………………………………...16 Table 1.3. List of major disease resistance and pest resistance genes transferred from section Sitopsis species of the genus Aegilops into wheat……………………………….18 Table 1.4. Summary of the taxonomic classifications of Aegilops longissima ………….19 Table 1.5. Summary of the ex situ genetic resources of Aegilops longissima in genebanks worldwide………………………………………………………………………………..20 Table 1.6. Collection sites, corresponding longitude/latitude data and number of Aegilops longissima accessions used in this study………………………………………………...23 Chapter 2 Table 2.1. Collection sites and number of Aegilops longissima accessions used in the evaluation of agro-morphological traits. ………………………………………………...50 Table 2.2. Mean, minimum, maximum, standard deviation (SD) and coefficient of variation (CV) values for 11 agro-morphological traits scored on 337 and 362 accessions of Aegilops longissima in Experiment 1 and Experiment 2 in the greenhouse, respectively. ……………………………………………………...……………………...53 Table 2.3. Correlation coefficients among 11 agro-morphological traits evaluated on Aegilops longissima in the greenhouse. ………………………………………………....55 Table 2.4. Spatial autocorrelation of agro-morphological trait values among Aegilops longissima accessions collected at neighboring sites in Israel as assessed by Global Moran’s I. ………………………………………………………………………………..57 Table 2.5. Ordinary Least Square analysis between agro-morphological traits of Aegilops longissima and 16 bioclimatic variables. ………………………………………………..58 vii Chapter 3 Table 3.1. Collection sites, corresponding longitude and latitude coordinates and number of Aegilops longissima accessions used in this study. ………………………...………...89 Table 3.2. Race, isolate, virulence phenotype and source of wheat rust pathogens used to evaluate resistance in Aegilops longissima . ………………………………………...…...92 Table 3.3. Number and percentage of Aegilops longissima accessions exhibiting resistant, susceptible and heterogeneous reactions to three wheat rust pathogens and corresponding values for Shannon’s diversity and equitability indices. ………………...93 Table 3.4. Spatial autocorrelation (Global Moran’s I) of the autocorrelation between collection sites of Aegilops longissima