Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1972 Penetration and the Host-Parasite Interface of Phytophthora Infestans on Tomato Leaf Tissue. Alice Sheppard badgett eT mplet Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Templet, Alice Sheppard badgett, "Penetration and the Host-Parasite Interface of Phytophthora Infestans on Tomato Leaf Tissue." (1972). LSU Historical Dissertations and Theses. 2364. https://digitalcommons.lsu.edu/gradschool_disstheses/2364 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. 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University Microfilms 300 North Zeeb Road Ann Arbor, Michigan 48106 A Xerox Education Company I 73-13,688 TEMPLET, Alice Sheppard Badgett, 1943- PENETRATION AND THE HOST-PARASITE INTERFACE OF PHYTOPHTHORA INFESTANS ON TOMATO LEAF TISSUE. The Louisiana State University and Agricultural and Mechanical College, Ph.D., 1972 Botany University Microfilms,A XEROX Company, Ann Arbor, Michigan © 1973 ALICE SHEPPARD BADGETT TEMPLET ALL RIGHTS RESERVED THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED. PENETRATION AND THE HOST-PARASITE INTERFACE OF PHYTOPHTHORA INFESTANS ON TOMATO LEAF TISSUE A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Plant Pathology by Alice Sheppard Badgett Templet B.A., Duke U n iv e rsity , 1965 M.S., Louisiana S ta te U n iv e rsity , 1968 December 1972 PLEASE NOTE: Some pages may have indistinct print. Filmed as received. University Microfilms, A Xerox Education Company ACKNOWLEDGEMENTS Sincere appreciation is extended to Dr. L. L. Black for his guidance and advice during the course of this study and the final preparation of this manuscript. S pecial thanks are expressed to Mr. H. W hitecross and Dr. A. B. Merkle for instruction in the preparation and examination of material for the scanning electron microscope in the School of Geoscience. Appreciation is extended to Dr. S. J. P. Chilton of the Department of Plant Pathology and to Dr. C. A. Schexnayder of the Department of Botany for making electron microscope materials and facilities available. In addition, gratitude is expressed to Drs. G. E. Holcomb, K. S. Derrick, N. L. Horn, C. A. Schexnayder, and M. D. Socolofsky for helpful criticism in the preparation of this manuscript. TABLE OF CONTENTS Page Acknowledgement....................... ............................................. i Table of Contents.............................. i i List of Illustrations........................................................................ i i i A b s tra c t.......................................................... .. ....................................... iv I. Introduction...................................................... 1 II. Materials and Methods................... 3 III. Results............................................................................................. 8 A. Scanning ElectronMicroscopy... ........................... 8 B. Leaf C le a rin g s............................................................................... 14 C. H isto lo g y ........................................................................................... 19 IV. Discussion................................................................................................... 39 A. Scanning Electron Microscopy............................................ 39 B. Leaf C le a rin g s .............................................................................. 41 C. H is to lo g y ................ 43 V. Summary............................................. 30 VI. Literature C ited................................. ^2 VII. V ita ........................................................ 56 i i LIST OF ILLUSTRATIONS Page I. Scanning Electron Microscopy Fig. 1-11....................................................................... 11-13 II. Leaf Clearings Fig. 12-21..................................................................... 16-18 III. Histology Fig. 22-67 ............................................... 27-38 i i i ABSTRACT Tomato leaf tissue inoculated with race 1 (compatible) and race 0 (incompatible) of Phytophthora infestans (Mont.) de Bary was examined with light, scanning electron and transmission electron microscopes. Germinated zoospores and sporangia were observed on the inoculated leaf surface. Germ tubes of sporangia had penetrated epidermal cells directly; others had entered through stomatal open­ ings. Hyphae from surface mycelium were observed to pass through stomatal openings. Intercellular mycelium ramified between the palisade mesophyll cells, penetrating host cells with one to several long, curved haustoria. Mycelium was found intracellularly in xylem vessels of tomato leaflets. A matrix which stained differently than the fungal or host cell wall was found between the cell walls of the host and parasite. Similar material was present between adjacent mycelial s tra n d s . The initial stage in the development of a haustorium is the initiation of a papilla-like structure of modified host cell wall material at the point where the fungus and the host cell come in contact. This is followed by the development of a young capitate haustorium which is surrounded by a sheath of modified cell wall material often containing particulate material. A mature haustorium has a constricted neck where it passes through the host wall. A collar of sheath material encircles the basal portion of the haustorium. The distal portion of the haustorium is not covered iv by a sheath, thus the haustorial cell wall appears to lie directly against the host plasma membrane. Swollen endoplasmic reticulum, increased golgi activity, distorted mitochondria, chloroplast destruction and wall lesions were observed in cells of infected leaves. Most of these effects on host cells were observed in the leaf lesion area whether or not the cell was penetrated by haustoria. v INTRODUCTION The .infection process and the anatomical relationship between a plant pathogen and its host have been the subject of numerous morphological studies. Light, scanning electron and transmission electron microscopes have been used to study the host-parasite interface of certain diseases. The results of these studies have contributed to an understanding of the process of pathogenesis. Review articles of the infection process of plant cells and/or surfaces by fungal pathogens have been written by Wood (30) and Ehrlich and Ehrlich (11). Phytophthora infestans (Mont.) de Bary, the causal agent of the late blight disease of potato and tomato plants, is a very destructive pathogen. Under extreme conditions, it causes total crop failure. Most of the research on the late blight disease has been directed toward a study of the physiology, etiology and anatomy of the disease on the economically important potato plant. Blackwell (5) made an extensive light microscopic study of the haustoria of P. infestans in potato tuber and leaf tissue. Pristou and Gallegly (21), Tomiyama (27), Takakuwa and Tomiyama (26) and Sakuma and Tomiyama (25) presented work related to the infection process of the late blight pathogen on potato tissue. Ehrlich and Ehrlich (12) conducted an electron microscopic study of the hyphae