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...