XVI International Botanical Congess

A characteristic feature associated with the expression of disease resistance in plants is the rapid death of small numbers of cells at the micro-organism invasion site. Evidence is increasing that this hypersensitive response (HR) is a form of programmed cell death(PCD) that shares some characteristics with PCD in animals, particularly during the execution phase. However, in contrast to mammalian PCD, there is no consistent morphology of the dying cell that uniquely identifies the HR and the sequence of cellular events may vary between different pathosystems, perhaps reflecting different modes of HR induction. Nevertheless, the HR elicits a characteristic set of local and systemic responses within the plant that enhances resistance to subsequent pathogen invasion. Rapid progress is being made in identifying genes that may be involved in the regulation of the HR.