DISEASE RESISTANCE OF PLANTS

Plants are exposed to a large variety of potentially pathogenic microb es. Apart from preformed barriers against infections, they have evolve d active defense mechanisms that enable them to resist attacks by path ogens. These defense reactions include genetically determined race-spe cific resistance and physiologically inducible resistance phenomena. A summary is presented of experimental results obtained in recent years that have brought major advances in the understanding of the mechanis ms underlying both race-specific resistance and systemic acquired resi stance.