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Mankind, throughout history, has strived to improve his food sources. By means of slow and empirical selections, it has been possible to greatly increase both quantity and quality of plant crops. This procedure has brought the most useful cereals to a state of refinement that seems to be difficult to further improve by the same methodology. Indeed, natural sexual mechanisms were always used to cross closely related sexually and genetically compatible organisms; the selection procedure consisted of isolating the most promi­ sing progenies. Obviously, by this way, plants could only share preexisting genetic pools. On the other hand, the last decade has seen drastic modifi­ cations of the experimental plant sciences, with the appearance of new technological possibilities. Because of this profound reshaping of our experimental ap­ proaches, other means can now be realistically envisaged in order to achieve similar or even higher goals. It is, for instance, possible to attempt completing sexual crosses (where both male and female gametes bring together the genetic informations necessary for growth and development of the offspring) by parasexual means by which novel genetic informa­ tions could possibly be added to the heritage •. At the limit, such genetic manipulations could enable man to create plants capable of producing new substances characteris­ tic of unrelated plants or, more generally, of other living or­ ganisms. Even if these possibilities might appear quite remote, the interest of Scientists has been awaken and, indeed, several at­ tempts to such genetic manipulations have already been made.

Studies in the Agricultural and Food Sciences: Plant Breeding for Pest and Disease Resistance presents a critical review of the development of resistant varieties of plant to pests and diseases. It discusses the economic impact of pests and diseases; the methods of controlling these pests and diseases; and the challenges being faced by a plant breeder. Some of the topics covered in the book are the general principles and methods of breeding for resistance; importance of parasite variability to the plant breeder; methods of testing for resistance; requirements for successful inoculation; production of resistant varieties; and economic importance of fungal diseases; and variability in fungal pathogen. Pathogenic fungi and fungal diseases are also covered. The control of fungal diseases by resistant varieties is discussed. An in-depth analysis of diseases in plants is provided. The characteristics of bacteria and bacterial diseases are also presented. A chapter is devoted to epidemiology of diseases associated with mycoplasma-like organisms and rickettsia-like organisms. The book can provide useful information to farmers, botanists, students, and researchers.

William C. Taylor Department of Genetics University of California Berkeley, California 94720 It is evident by now that there is a great deal of interest in exploiting the new technologies to genetically engineer new forms of plants. A purpose of this meeting is to assess the possibilities. The papers that follow are concerned with the analysis of single genes or small gene families. We will read about genes found within the nucleus, plastids, and bacteria which are responsible for agri­ culturally important traits. Given that these genes can be isolated by recombinant DNA techniques, there are two possible strategies for plant engineering. One involves isolating a gene from a cultivated plant, changing it in a specific way and then inserting it back into the same plant where it produces an altered gene product. An example might be changing the amino acid composition of a seed pro­ tein so as to make the seed a more efficient food source. A second strategy is to isolate a gene from one species and transfer it to another species where it produces a desirable feature. An example might be the transfer of a gene which encodes a more efficient pho­ tosynthetic enzyme from a wild relative into a cultivated species. There are three technical hurdles which must be overcome for either strategy to work. The gene of interest must be physically isolated.

In this volume of Recent Advances in Phytochmistry you will find a record of the pioneering attempts of plant biochemists and molecular biologists to modify the patterns of secondary metabolism in plants, as presented at the 33rd annual meeting of the Phytochemical Society of North America, in Asilomar, California, on June 27 -July I, 1993. The studies described here represent a marriage of the newest of technologies with one of the oldest human activities, exploitation of plant chemistry. They also represent the beginning of a new era of phytochemical research, an era that will undoubtedly begin to provide answers to some of the long-standing questions that have absorbed plant biochemists for the past century. There is, for instance, a common deflating experience to which every worker in the area of plant secondary metabolism can probably relate. After hearing about the latest research findings regarding some aspect of remarkable compound'X', someone in the audience finally directs the inevitable question at the hapless speaker.'Tell me, is anything known as to the biological role of compound'X'in the plant?'The answer, in most cases, must be'essentially nothing'! This is a frustrating scenario for both the speaker and the audience, since the very fact that a complex biosynthetic pathway remains encoded in a plant genome points to an associated selective advantage. The problem is that establishing the nature and scale of that advantage is a very complex task.

Environmental stresses represent the most limiting factors for agricultural productivity worldwide. These stresses impact not only current crop species, they are also significant barriers to the introduction of crop plants into areas that are not currently being used for agriculture. Stresses associated with temperature, salinity and drought, singly or in combination, are likely to enhance the severity of problems to which plants will be exposed in the coming decades. The present book brings together contributions from many laboratories around the world to discuss and compare our current knowledge of the role stress genes play in plant stress tolerance. In addition, strategies are discussed to introduce these genes and the processes that they encode into economically important crops, and the effect this will have on plant productivity.

There are clearly many directions in which the further development of the GUS gene fusion system can progress. Some of these have been outlined above, but others can be imagined. There are no reasons to limit our conceptions of the use of GUS gene fusions to analysis and manipulation of single genes. We can envision numerous marked genes - perhaps with several new fusion systems - giving valuable information about gene interaction, or population structure. The study of plan- pathogen and plant symbiont interactions can progress rapidly with simple quantitative markers for genes and individuals. We can imagine ways of using gene fusions to report on crop physiology or other complex phenotypes, thereby enhancing the accuracy and speed of screening. Introduction of the biosynthetic pathway for glucuronide detoxification by expressing genes for the UDP-glucuronyl transferases in plants may result in novel mechanisms for plants to deal with xenobiotics such as insecticides or herbicides. Synthesis of substrates, which until now has been performed chemicall- resulting in expensive compounds - can be done biosynthetically. This should make the system not only the most powerful gene fusion system for agriculture, but also the most accessible.

Proceedings of the 7th International Protoplast Symposium, Wageningen, The Netherlands, December 6-11, 1987

Since the first commercial introduction of transgenic corn plants in 1995, biotechnology has provided enormous benefits to agricultural crop production. Research is underway to develop a much broader range of genetically engineered organisms (GEOs), including fish, trees, microbes, and insects, that could have the potential to transform fields such as aquaculture, biofuels production, bioremediation, biocontrol, and even the production of pharmaceuticals. However, biotechnology is not without risk and continues to be an extremely controversial topic. Chief among the concerns is the potential ecological effects of GEOs that interact with wildlife and habitats. The U.S. Geological Survey (USGS) is charged with providing scientific advice to inform federal agencies that manage wildlife and their habitats. USGS has identified biotechnology as one of its major challenges for future research. Seeing an opportunity to initiate a dialogue between ecologists and developers of GEOs about this challenge, the USGS and the National Research Council (NRC) held a two-day workshop in November of 2007, to identify research activities with the greatest potential to provide the information needed to assess the ecological effects of GEOs on wildlife and habitats. The workshop, designed to approach the research questions from a habitat, rather than transgenic organism, perspective, is summarized in this book.

Plant biotechnology offers important opportunities for agriculture, horticulture, and the pharmaceutical and food industry by generating transgenic varieties with altered properties. This is likely to change farming practice and reduce the potential negative impact of plant production on the environment. This volume shows the worldwide advances and potential benefits of plant genetic engineering focusing on the third millennium. The authors discuss the production of transgenic plants resistant to biotic and abiotic stress, the improvement of plant qualities, the use of transgenic plants as bioreactors, and the use of plant genomics for genetic improvement and gene cloning. Unique to this book is the integrative point of view taken between plant genetic engineering and socioeconomic and environmental issues. Considerations of regulatory processes to release genetically modified plants, as well as the public acceptance of the transgenic plants are also discussed.This book will be welcomed by biotechnologists, researchers and students alike working in the biological sciences. It should also prove useful to everyone dedicated to the study of the socioeconomic and environmental impact of the new technologies, while providing recent scientific information on the progress and perspectives of the production of genetically modified plants.The work is dedicated to Professor Marc van Montagu.

Gentechnisch veränderte herbizidresistente Pflanzen eröffnen neue Optionen der chemischen Unkrautbekämpfung, sie erweitern den Anwendungsbereich von nichtselektiven Herbiziden, die bisher nicht eingesetzt werden konnten, weil sie auch die Kulturpflanzen angreifen. Herbizidresistenz ist eines der ersten Projekte zur Anwendung der Gentechnik in der Pflanzenzüchtung. Die Perspektiven dieser Technik haben in der Öffentlichkeit kontroverse Diskussionen ausgelöst, vor allem über die möglichen Risiken der Anwendung und Freisetzung transgener Pflanzen. In einem neuartigen diskursiven Verfahren zur Technikfolgenabschätzung für den Anbau von Kulturpflanzen mit gentechnisch erzeugter Herbizidresistenz wurden die Themen der öffentlichen Kritik aufgenommen und im Dialog zwischen Befürwortern und Gegnern diskutiert. In diesem Buch sind die Ergebnisse der Fachgutachten und der Diskussion der politischen und rechtlichen Folgen zusammengefaßt.