Developments in Plant Pathology – serie

There is an increasing need for an understanding of the fundamental processes involved in the mechanisms by which disease resistances are introduced into crop plants. This book provides a wide-ranging coverage of the successes and failures of the classical techniques; it describes the advances towards modern technology and addresses the problems of pathogen variation. Crop plants that are considered include: cereals (wheat, barley, rice), potatoes, vegetables and soft fruits.

A collection of papers that give a comprehensive description of the major areas of research on the interactions between plants and their pathogens. State-of-the-art knowledge about research on microbial avirulence genes and plant resistance genes, about pathogenicity factors and signals for establishment of infection, about elicitors and intermediates in the signalling pathway, and about the genes involved in plant responses to pathogens and environmental stress is reviewed. The different topics covered show that modern tools of plant cellular and molecular biology are now available to investigate very significant models of plant-pathogen interactions and to identify the molecular determinants of the two partners that trigger defence responses, the signals involved and the mechanism of their transduction, the spatial and temporal regulation of defence gene expression in relation to the spread or localization of the pathogen. The first trials to exploit these results for enhancing plant resistance and crop field by biotechnology are presented. The book is a main reference source for research scientists and advanced students.

Induced or acquired resistance to disease in plants has been known for many years, but the phenomenon was studied in only a few laboratories until about a decade ago. Since then, there has been an increasing interest in induced resistance as a new, environmentally safe means of disease control, as well as a model for the study of the genes involved in host defence and the signals that control them. This increased interest led the editors of this book to collect and summarize much of the current and older literature on the topic in a single volume. Each chapter covers its topic as comprehensively as possible, thus serving as a solid introduction to the literature, as well as expressing its writer's own views on the state of research in the area and giving an indication of where future research may lead. This text addresses the biology of induced resistance in legumes, solanaceae, cucurbits and monocots, since these are the families that have received the most attention, followed by a discussion of the molecular basis of induced resistance, its genetic and evolutionary significance, and practical applications in disease control.It should provide a background for those commencing work in the area, as well as a source of information for established workers who wish to learn about other areas of induced resistance.

The coconut palm is a very important plant in the tropical regions, both as a cash crop and in subsistence agriculture. Although most coconut production is dedicated to copra and its subsequent oil extraction, the number of products that can be obtained from the palm is seemingly limitless. However, the coconut industry has several problems that affect its productivity, especially: the use of unimproved planting material, the old age of existing plantations, and various pests and diseases. This book deals with the most severe of the diseases, lethal yellowing, which has killed millions of coconut palms in Latin America and the Caribbean alone and which, together with related diseases in Africa and possibly India and Southeast Asia, poses a world-wide threat to coconut production. The papers were presented to a symposium on "Lethal Yellowing Research and Practical Aspects", held in Mexico in November 1993. The book should help to maintain the momentum in lethal yellowing research, stimulating further research on coconut palms, an orphan crop having many uses.

The family Trichodoridae was established by Thorne in 1935 but it remained of limited taxonomie interest until 1951 when Christie and Perry associated Trichodorus christie (now Paratrichodorus minor) with a "stubby root disease" that affected certain crops in Florida, USA and interest further increased from 1960 when P. pachydermus was implicated as a vector of the economically important tobacco raule virus. Such discoveries gave an impetus to studies on many aspects of the biology of trichodorid nematodes with a consequent proliferation of new species described from different parts of the world. The number of species increased from twelve in 1957 to a present day total exceeding eighty. This rapid expansion in the number of species was accompanied by several reappraisals of the taxonomy and systematies of the family, the most notable changes being the creation of the genus Paratrichodorus by Siddiqi in 1974 and the recognition of the monodelphic genera Monotrichodorus and Allotrichodorus respectively by Andrassy in 1976 and Rodriguez-M, Sher and Siddiqi in 1978. Reliable and unambiguous identification of taxa is dependent on the known reliability of a range of characters, whieh remains of paramount importance in taxonomy even when biochemical and molecular methodology is available. In this book each of the species, including synonyms and species inquirenda, that comprise the family Trichodoridae is re-described from meticulous mieroscopie examination of type specimens, material from official nematode collections and populations in the field.

Micro-organisms, including those genetically modified (GMOs), are increasingly being released deliberately into the environment for different purposes. One major interest is the use of antagonistic organisms for biological control of pests and plant diseases. Both in the development of biocontrol agents and their later risk assessment and product approval, there is a need for methods that facilitate monitoring of such introduced microorganisms. This book addresses the various approaches for monitoring introduced fungi and the current status of techniques which may be relevant to use are described. Such techniques include marker genes and other DNA-based techniques, serology using polyclonals or monoclonals, the use of enzymes or secondary metabolite profiles, and "electronic noses" as well as more traditional methods like dilution plating.

During the 1990s, research on Pseudomonas syringae pathovars and related pathogens has progressed rapidly, opening up many new avenues. The application of molecular genetics has provided insights into determinants of pathogenicity and virulence. Progress has also been made in elucidating the chemical structures and modes of action of phytotoxins from Pseudomonas syringae; by establishing strategies for disease control; in biotechnological applications; by studying the resistant reaction of the plant with a combined biochemical and genetic approach; and in the development of detection and identification methodologies as tools in epidemiological studies. In a response to such rapid advances, this volume is an attempt to provide a balanced overview of recent developments in the field. At the beginning of each chapter is a critical review by international experts.

In 1992 a Concerted Action Programme (CAP) was initiated by Peter Sijmons with the purpose of intensifying collaborations between 16 European laboratories working on plant-parasitic nematodes. The four-year programme entitled "Resistance Mechanisms Against Plant-Parasitic Nematodes" focused on molecular aspects of the interaction between sedentary nematodes and plants on the model system Arabidopsis and on novel resistance strategies. Funding was provided mainly for exchange visits between collaborating laboratories and for the organization of annual meetings. During the last annual meeting which was held in May 1996 in Toledo, Spain, Carmen Fenoll initiated the production of this volume. The text presents a series of current reviews, each written by one of the participating laboratories, which include the scientific progress achieved in the frame of this CAP but are by no means limited in scope to this work.

This book is based mainly on invited and offered papers presented at the Second International Symposium on Bacterial and Bacteria-like Contaminants of Plant Tissue Cultures held at University College, Cork, Ireland in September 1996, with additional invited papers. The First International Symposium on Bacterial and Bacteria-like Contaminants of Plant Tissue Cultures was held at the same venue in 1987 and was published as Acta Horticulturae volume 225, 1988. In the intervening years there have been considerable advances in both plant disease diagnostics and in the development of structured approaches to the management of disease and microbial contamination in micropropagation. These approaches have centred on attempts to separate, spatially, the problems of disease transmission and laboratory contamination. Disease-control is best achieved by establishing pathogen-free cultures while laboratory contamination is based on subsequent good working practice. Control of losses due to pathogens and microbial contamination in vitro addresses, arguably, the most importance causes of losses in the industry; nevertheless, losses at and post establishment can also be considerable due to poor quality microplants or micro-shoots. In this symposium, a holistic approach to pathogen and microbial contamination control is evident with the recognition that micropropagators must address pathogen and microbial contamination in vitro, and diseases and microplant failure at establishment. There is increasing interest in establishing beneficial bacterial and mycorrhizal association with microplants in vitro and in vivo.

The Tottori International Symposia on Host-Specific Toxins were established in 1988 by the Tottori University Faculty of Agriculture to provide an interdisciplinary forum for scientists working in rapidly emerging areas of studies of plant-fungal pathogen interactions, especially involving host-specific toxins and related pathogenicity factors. This work presents the proceedings of the 3rd International Symposium on Host-Specific Toxins held in August 1997 in Tottori, Japan. Up-to-date material is presented in rapidly developing research areas such as new toxins, fungal genes for toxin biosynthesis, evolution of pathogenic strategies, toxin actions on plants, toxin receptors, signal transduction, oxidative burst, mechanisms of sensing, penetration and host degradation, apoptosis triggered by toxins, and plant genes for detoxification. This information has given researchers insights into various aspects in the field. This work represents a reference for researchers and students in the areas of plant pathology, plant protection, plant physiology and molecular biology, fungal molecular genetics, and plant breeding and biotechnology.

This book offers a concise yet comprehensive treatment of its subject matter. It begins with a short overview of Finland's geography and population, political and legal system, and economy. The Introduction further discusses the history of the labour relations system and the role of government organs within the system. Part I discusses the law of the individual employment relationship: the individual employment contract; rights and duties of the contract parties; health and safety at work; employee privacy; working time and annual vacations; job security and other matters concerned with the end of the relationship; protection against discrimination; and settlement of disputes over rights. In Part II, collective labour relations are discussed: trade union freedom; the associations network; workplace participation and other institutionalized relations between employers and employees; general framework and law of collective agreements; and industrial action.

Emphasis in this second volume of "Advances in Downy Mildew Research" is on the biology of compatible interactions, forecasting and epidemiology, host specialisation, genetic variability amongst pathogen populations, novel methods for detection and systematics, and induced resistance. Two chapters focus on the related oomycete Albugo candida, which shares many pathogenic characteristics with the downy mildews and provides a valuable comparative pathosystem. Contributions on specific downy mildews include Bremia lactucae, Peronospora destructor, Peronospora sparsa, Peronospora viciae, Plasmopara halstedii, Plasmopara viticola, Pseudoperonospora cubensis and Sclerospora graminicola. Review chapters on compatibility, forecasting and systematics consider a broader range of downy mildew fungi, and compare them with other oomycete and biotrophic pathogens. The book is relevant to anyone with an interest in these unique biotrophic pathogens, either in their own right as causes of damaging diseases or as model systems for research on host-pathogen interactions.It should be read by: students, teachers and researchers in academic and research institutes; research and development personnel in the agrochemical industries; agricultural and horticultural advisers, and other extension workers.

There is an increasing need for an understanding of the fundamental processes involved in the mechanisms by which disease resistances are introduced into crop plants. This book provides a wide-ranging coverage of the successes and failures of the classical techniques; it describes the advances towards modern technology and addresses the problems of pathogen variation. Crop plants that are considered include: cereals (wheat, barley, rice), potatoes, vegetables and soft fruits.

Induced or acquired resistance to disease in plants has been known for many years, but the phenomenon was studied in only a few laboratories until about a decade ago. Since then, there has been an increasing interest in induced resistance as a new, environmentally safe means of disease control, as well as a model for the study of the genes involved in host defence and the signals that control them. This increased interest led the editors of Induced Resistance to Disease in Plants to collect and summarise much of the current and older literature on the topic in a single volume. Each chapter covers its topic as comprehensively as possible, thus serving as a solid introduction to the literature, as well as expressing its writer's own views on the state of research in the area and giving an indication of where future research may lead. Induced Resistance to Disease in Plants addresses the biology of induced resistance in legumes, solanaceae, cucurbits and monocots, since these are the families that have received the most attention, followed by a discussion of the molecular basis of induced resistance, its genetic and evolutionary significance, and practical applications in disease control. The book will provide a background for those commencing work in the area, as well as a source of information for established workers who wish to learn about other areas of induced resistance.

The family Trichodoridae was established by Thorne in 1935 but it remained of limited taxonomie interest until 1951 when Christie and Perry associated Trichodorus christie (now Paratrichodorus minor) with a "stubby root disease" that affected certain crops in Florida, USA and interest further increased from 1960 when P. pachydermus was implicated as a vector of the economically important tobacco raule virus. Such discoveries gave an impetus to studies on many aspects of the biology of trichodorid nematodes with a consequent proliferation of new species described from different parts of the world. The number of species increased from twelve in 1957 to a present day total exceeding eighty. This rapid expansion in the number of species was accompanied by several reappraisals of the taxonomy and systematies of the family, the most notable changes being the creation of the genus Paratrichodorus by Siddiqi in 1974 and the recognition of the monodelphic genera Monotrichodorus and Allotrichodorus respectively by Andrassy in 1976 and Rodriguez-M, Sher and Siddiqi in 1978. Reliable and unambiguous identification of taxa is dependent on the known reliability of a range of characters, whieh remains of paramount importance in taxonomy even when biochemical and molecular methodology is available. In this book each of the species, including synonyms and species inquirenda, that comprise the family Trichodoridae is re-described from meticulous mieroscopie examination of type specimens, material from official nematode collections and populations in the field.

This book is based on papers presented at the Second International Symposium on Bacterial and Bacteria-like Contaminants of Plant Tissue Cultures held at University College, Cork, Ireland in September 1996, with additional invited papers. Since the first symposium (published as Acta Horticulturae 225, 1988), there have been considerable advances in both plant disease diagnostics and in the development of structured approaches to the management of disease and microbial contamination in micropropagation. These approaches have centered on attempts to separate, spatially, the problems of vertical disease transmission, via infected explants to progeny microplants, from laboratory contamination. Disease control is best achieved by establishing pathogen-free cultures, while laboratory contamination management is based on subsequent good working practice. Control of losses due to pathogens and microbial contamination in vitro addresses, arguably, the most important causes of losses in the industry; nevertheless, losses at and post establishment can also be considerable due to poor quality micro-propagules.In this book, a holistic approach to pathogen and microbial contamination control is evident with the recognition that micropropagators must address pathogen and microbial contamination in vitro, and diseases and microplant failure at establishment. There is increasing interest in establishing beneficial bacterial and mycorrhizal association with microplants in vitro and in vivo. The contents are divided into sections. In each section there are papers that update contributions offered at the first symposium; for example, major advances have been made in microbial taxonomy and diagnostics based on advances in DNA-based techniques. Consolidation has occurred in therapy and laboratory contamination management. Novel, and arguably speculative, in vitro contamination control based on autotrophic culture is described; and disease control at establishment using bacterial and mycorrhizal inoculants is discussed.

Advances in Rice Blast Research provides a complete overview of the research undertaken on the rice-blast pathosystem. This book gathers in one volume the most recent works on rice blast fungus genetics and molecular biology of pathogenicity, rice blast fungus population studies, and genetics and molecular biology of rice resistance to blast, including resistance gene cloning. It also presents the latest results on resistance breeding and resistance management strategies, epidemiology and disease management. This book is a must for plant pathologists and breeders working on rice blast and also to plant pathologists and breeders dealing with fungal diseases in general, because the rice-blast pathosystem is a model in plant pathology. Advances in Rice Blast Research provides a complete overview of the research undertaken on the rice-blast pathosystem. This book gathers in one volume the most recent works on rice blast fungus genetics and molecular biology of pathogenicity, rice blast fungus population studies, and genetics and molecular biology of rice resistance to blast, including resistance gene cloning. It also presents the latest results on resistance breeding and resistance management strategies, epidemiology and disease management. This book is a must for plant pathologists and breeders working on rice blast and also to plant pathologists and breeders dealing with fungal diseases in general, because the rice-blast pathosystem is a model in plant pathology.

Emphasis in this second volume of Advances in Downy Mildew Research is on the biology of compatible interactions, forecasting and epidemiology, host specialisation, genetic variability amongst pathogen populations, novel methods for detection and systematics, and induced resistance. Two chapters focus on the related oomycete Albugo candida, which shares many pathogenic characteristics with the downy mildews and provides a valuable comparative pathosystem. Contributions on specific downy mildews include Bremia lactucae, Peronospora destructor, Peronospora sparsa, Peronospora viciae, Plasmopara halstedii, Plasmopara viticola, Pseudoperonospora cubensis and Sclerospora graminicola. Review chapters on compatibility, forecasting and systematics consider a broader range of downy mildew fungi, and compare them with other oomycete and biotrophic pathogens. The book is relevant to anyone with an interest in these unique biotrophic pathogens, either in their own right as causes of damaging diseases or as model systems for research on host-pathogen interactions.It should be read by: students, teachers and researchers in academic and research institutes; research and development personnel in the agrochemical industries; agricultural and horticultural advisers, and other extension workers.

When I received an invitation to attend the International Symposium on Lethal Yellowing being organised by the Centro de Investigacion Cientifica de Yucatan (CICy), I was excited and a little nostalgic. During the 1970s, a series of similar symposia had been held under the auspices of the loosely-constituted "International Council on Lethal Yellowing" (ICL Y). These were the years when the MLO cause for L Y was first proposed, a vector was found, the disease was racing across mainland Florida, USA and it was suspected of having jumped to Cozumel. Analogous diseases were also reported to be spreading in Africa and elsewhere. The ICL Y meetings, held approximately every two years, proved to be an immensely valuable forum for all involved in the research and control of L Y. They attracted a very wide cross-section of scientists and practitioners working on L Y, on related diseases, and on palms in general. Many participants of those ICL Y meetings also attended this CICY Symposium. Unfortunately, during the 1980s, as countries learned to live with L Y, most of the national and international funding for L Y research dried up, and so did ICL Y. The present symposium is the only international meeting to have been devoted to L Y since the last meeting of rCLY in 1979. Its convening in Merida is timely.

The growing body of information on bacteria pathogenic for humans, mammals and plants generated within the past ten years has shown the interesting conservation of newly identified genes that playa direct role in the pathogenic mechanism. In addition to these genes, there are also genes that confer host specificities and other traits important in pathogenesis on these pathogens. In this volume, we have organized the subject areas to best fit the concept on the way bacterial pathogens recognize, interact and invade the host, on the regulation of genes involved in virulence, on the genes involved in the elaboration of toxins and other pathogenic components such as iron sequestering proteins, and on the mechanisms of circumventing the host defense systems. These areas are divided into Sections. Section I covers the first step when the pathogen seeks its host, and Sections II through VI cover subsequent steps leading to pathogenesis while avoiding host defenses. We conclude this work with a chapter summarizing information on examples of virulence mechanisms that are highly conserved.

Research on the mechanisms of plant defense responses to stress and pathogen attack has attracted much attention in recent years. This increasing interest stems from the fact that the tools of molecular biology now enable us to study the molecular basis of old biological concepts such as host-pathogen recognition (and particularly the gene­ for-gene relationship), hypersensitive cell death and systemic acquired resistance. Our knowledge about avirulence and resistance genes, elicitors, signal transduction and genes involved in plant defense is rapidly expanding. Moreover we are just beginning to test in planta the potential of these results for biotechnological applications, aimed at improving plant resistance to diseases. The 2nd Conference of the European Foundation for Plant Pathology, hosted by the "Societe Fran~aise de Phytopathologie", was devoted to "Mechanisms of plant defense responses" and was held in Strasbourg, France. It brought together over 350 scientists from universities, research institutes and private sectors of 24 countries. Major advances in the areas under study have been reviewed in plenary lectures and are developed in the main articles of this book. Over 160 high-quality posters were presented and are summarized in short articles. Data from outstanding posters, which were discussed after a short oral presentation, are found in extended articles. As a whole the book presents a collection of papers arranged in six sections and reflecting the present day state-of-the-art of research in the field of plant defense reactions.

For investigators engaged in the study of toxins generally, and host-specific toxins in particular, it is a rare treat to attend a meeting in which toxins involved in plant pathogenesis are emphasized. A gathering of this type provides opportunity to consider the discovery of new toxins, their chemical structures, genes encoding enzymes that control their biosyntheses, their sites of action and physiological effects on plants, and their roles (if any) in pathological processes. Having acknowledged the inspiration fostered by a 'toxin meeting', however, it is important to point out that the program of this symposium was generously sprinkled with 'nontoxin' talks. These contributions generated cross-disciplinary discussion and promoted new ways of thinking about relationships among factors required for plant disease development. The point can be illustrated by considering just one example. We have in the past often regarded diseases mediated by host-specific toxins and diseases involving 'gene-for-gene' relationships as representing two different classes of fungal/plant interaction. This is largely because the key molecular recognition event in so-called 'toxin' diseases leads to compatibility, whereas the corresponding event in 'gene-for-gene' diseases leads to incompatibility. Yet the race specific elicitors produced by the 'gene-for-gene' fungi Cladosporium fulvum (De Wit, Adv. Bot. Res. 21:147- 185, 1995) and Rhynchosporium secalis (Rohe et a1. , EMBO J.

During the last decade, research on Pseudomonas syringae pathovars and related pathogens has progressed rapidly, opening up many new avenues. The application of molecular genetics has provided new insights into determinants of pathogenicity and virulence. Progress has also been made in elucidating the chemical structures and modes of action of phytotoxins from Pseudomonas syringae; by establishing novel strategies for disease control; in biotechnological applications; by studying the resistant reaction of the plant with a combined biochemical and genetic approach; and in the development of new detection and identification methodologies as tools in epidemiological studies. With such rapid advances it becomes more and more difficult to keep abreast of the developments and concepts within disciplines, all involving research on pathovars of P. syringae. In an attempt to provide a balanced overview, recent developments in these rapidly expanding fields have been critically reviewed at the beginning of each chapter by internationally renowned experts. Our comprehensive coverage has been made possible because all the contributors to this volume presented their latest findings at the `5th International Conference on Pseudomonas syringae Pathovars and Related Pathogens' in Berlin, September 3-8, 1995. In this way, it was possible to bring together contributions from a wide range of fields including phytopathology, genetics, bacteriology, plant breeding, plant protection, and taxonomy. This book is not intended simply as a record of the proceedings of the Berlin Conference, but as an extension of recent findings and hypotheses put forward at the meeting. All papers published in this volume have been reviewed by the Editors.

In 1992 a Concerted Action Programme (CAP) was initiated by Peter Sijmons with the purpose of intensifying collaborations between 16 European laboratories working on plant-parasitic nematodes. The four-year programme entitled `Resistance mechanisms against plant-parasitic nematodes' focused on molecular aspects of the interaction between sedentary nematodes and plants on the model system Arabidopsis and on novel resistance strategies. Funding was provided mainly for exchange visits between collaborating laboratories and for the organization of annual meetings. During the last annual meeting which was held in May 1996 in Toledo, Spain, Carmen Fenoll initiated the production of this volume. The book presents a series of up-to-date reviews, each written by one of the participating laboratories, which include the scientific progress achieved in the frame of this CAP but are by no means limited in scope to this work.

The diagnosis and identification of plant pathogens provides the basis of plant pathology and phytomedicine. The Executive Committee of the EUROPEAN FOUNDATION FOR PLANT PATHOLOGY (EFPP) had no problem to identify this actual th topic as topic for the 4th Symposium, which was held from September 8 to the 12th at the University of Bonn. It was suggested to have introductory papers and papers on actual research on recently identified topics. The development of diagnosis and pathogen identification is very important to keep plants healthy and to provide a successful and efficient disease control. On the other hand the most important task of the EUROPEAN FOUNDATION FOR PLANT PATHOLOGY is to improve the international communication, especially in the European hemisphere. Another important duty is to provide the contact between all associated societies - of specific importance seems to be the contact to societies and colleagues from eastern European countries. Times have changed and gratefully we are obliged to hold the contact to our colleagues from the east. During the last meeting we could hold this contact to a certain extent and this should be a premise for the future. th During 1998 the EUROPEAN FOUNDATION FOR PLANT PATHOLOGY will join the 7 International Congress of Plant Pathology held at Edinburgh from August 9-14, 1998. th The 5 Symposium of the EUROPEAN FOUNDATION FOR PLANT PATHOLOGY will be arranged by our Italian colleagues.

Plants interact with a large number of microoganisms which have a major impact on their growth either by establishing mutually beneficial symbiotic relationships or by developing as pathogens at the expense of the plant with deleterious effects. These microorganisms differ greatly not only in their nature (viruses, phytoplasmas, bacteria, fungi, nematodes, ... ) but also in the way they contact, penetrate and invade their host. Histology and cytology have brought an essential contribution to our knowledge of these phenomena. They have told us for instance, how specialized structures of the pathogen are often involved in the adhesion and penetration into the plant, how the interface between both organisms is finely arranged at the cellular level, or what structural alterations affect the infected tissues. They have thus set the stage for the investigations of the underlying molecular mechanisms could be undertaken. Such investigations have been remarkably successful in the recent years, expanding considerably our understanding of plant-microorganism interactions in terms of biochemical changes, rapid modifications of enzymatic activities, coordinated gene activation, signal reception and transduction. Biochemistry, molecular biology and cellular physiology have taken precedence in the phytopathologist's set of methods.

Microorganisms, including those genetically modified (GMOs), are increasingly being released deliberately into the environment for different purposes. One major interest is the use of antagonistic organisms for biological control of pests and plant diseases. Both in the development of biocontrol agents and their later risk assessment and product approval, there is a need for methods that facilitate monitoring of such introduced microorganisms. This book particularly addresses the various approaches for monitoring introduced fungi and the current status of techniques which may be relevant to use are described. Such techniques include marker genes and other DNA-based techniques, serology using polyclonals or monoclonals, the use of enzymes or secondary metabolite profiles, and `electronic noses' as well as more traditional methods like dilution plating.