Genetics of plant-pathogen interactions

Progress has occurred in understanding the function of disease-resistance genes that govern the resistance of plants to pathogens, and pathogen-produced molecules, called elicitors, that resistance genes key on. Data support the elicitor-receptor model wherein resistant plants contain receptors for pathogen elicitors. This recognition may be complex, however, involving delivery of elicitors to plant cells by specialized pathogen secretion systems and their processing prior to perception. Furthermore, elicitor receptors may not be the resistance gene proteins that govern specificity of the system. It is now also recognized that many elicitors function as virulence factors for the pathogen but have been co-opted by plants as triggers for active resistance. Major recent advances in the cloning and sequencing of clustered plant disease-resistance genes are providing information on the basis of their recognitional specificities and offer the opportunity to engineer new genes that recognize refractory pathogens or exhibit increased efficacy and durability. In combination with the transformation of cloned disease-resistance genes into new plant species, these approaches should facilitate disease control strategies in practical agriculture.