Paradigm Genetics, Inc,; PO Box 14528; Research Triangle Park, NC 27709-4528, USA

Following an initial pathogen infection, many species of plants can be induced to resistance against further infection. Resistance can be systemic, long-lasting and effective against a broad spectrum of pathogens. This response has been referred to as systemic acquired resistance (SAR). In the past ten years, there has been significant progress in understanding molecular events that occur during the initiation and maintenance of SAR. This talk will review the current understanding of SAR and will detail some new results where 250,000 mutants of Arabidopsis have been screened for the constitutive expression of a PR-1 promoter/luciferase transgene. Over 1000 putative mutants were isolated and characterized. Of these 16 that do not show a lesion mimic morphology were selected for further study.
Analysis of these mutants suggests that there are at least 3 independent pathways that can lead to disease resistance in Arabidopsis.