Plant pathology embraces all aspects of biological and scientific activity which are concerned with understanding the complex phenomena of diseases in plants. Physiological plant pathology represents those specialities within plant pathology which focus on the physiological and biochemical activities of pathogens and on the response of host plant tissues. Today there is an increasing recognition on the part of the scientific agri cultural community that only through a deeper and more fundamental under standing of all the interacting components of the agricultural biota can we expect to improve our capabilities of feeding an expanding world population. It is in this context that physiological plant pathology has assumed new significance within the broader field of plant pathology. No longer are studies on the biochemistry and physiology of pathogens and pathogenesis merely isolated academic exercises; rather, a substantial coherent body of knowledge is accumulating upon which our understanding of the process of disease developmen t and host resistance is being founded. It is from these foundations of knowledge that ultimately new insights into the control of plant diseases may be expected to grow. It seems appropriate, therefore, that at regular intervals those involved in the various subspecialities encompassing the broadest aspects of physiological plant pathology reassess the contributions within the particular specialities in the light of new knowledge and technologies for the purpose of articulating new and productive directions for the future.

Toxins in Plant Disease presents a comprehensive coverage of plant disease toxins, both those for which there are reasonable evidence and those with fewer credentials. This book is primarily concerned with the mechanism wherein substances that interfere with metabolism or that alter the normal structure of protoplasm are produced and released (category 1); this includes the traditional toxins, which are usually of low molecular weight. It also describes category 2 mechanism, wherein substances that interfere with normal control of growth and development are produced and released; these microorganisms are classified as growth-affecting compounds. Moreover, this text addresses some high-molecular-weight compounds that contribute to vascular dysfunction. It further talks about the production, isolation, assay, genetics of production, mechanism of action, structure-activity relationship, metabolism, and applications of these toxins. This publication will provide a rational basis for future investigations and contribute to the eventual understanding of the role that toxins play in disease causation.

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.

Established almost 30 years ago, Methods in Microbiology is the most prestigious series devoted to techniques and methodology in the field. Now totally revamped, revitalized, with a new format and expanded scope, Methods in Microbiology will continue to provide you with tried and tested, cutting-edge protocols to directly benefit your research. - Focuses on the methods most useful for the microbiologist interested in the way in which bacteria cause disease - Includes section devoted to 'Approaches to characterising pathogenic mechanisms' by Stanley Falkow - Covers safety aspects, detection, identification and speciation - Includes techniques for the study of host interactions and reactions in animals and plants - Describes biochemical and molecular genetic approaches - Essential methods for gene expression and analysis - Covers strategies and problems for disease control

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.

This book offers a collection of information on successive steps of molecular 'dialogue' between plants and pathogens. It additionally presents data that reflects intrinsic logic of plant-parasite interactions. New findings discussed include: host and non-host resistance, specific and nonspecific elicitors, elicitors and suppressors, and plant and animal immunity. This book enables the reader to understand how to promote or prevent disease development, and allows them to systematize their own ideas of plant-pathogen interactions.* Offers a more extensive scope of the problem as compared to other books in the market* Presents data to allow consideration of host-parasite relationships in dynamics and reveals interrelations between pathogenicity and resistance factors* Discusses beneficial plant-microbe interactions and practical aspects of molecular investigations of plant-parasite relationships* Compares historical study of common and specific features of plant immunity with animal immunity