Suppression subtractive hybridization (SSH) was used to generate a cDNA library enriched for sequences induced in a late-blight-resistant potato cultivar undergoing the hypersensitive response (HR). Of 100 partial cDNA sequences submitted to international DNA and protein data bases, 42 showed similarity to 35 genes, of which 31 were from plants. Of these, 13 were previously characterized as either defense-, stress-, or senescence-associated. One sequence matched (75 to 81%) all known serine palmitoyltransferases (SPTs) at the protein level. SPT catalyzes the first committed step in the synthesis of sphingolipids, important signaling molecules involved in cell differentiation and apoptosis. Putative products of other genes identified here may play a role in programmed cell death, including protein degradation, DNA degradation, metal ion chelation, and signal transduction. cDNA-amplified fragment length polymorphism was used to confirm differential expression of sequences isolated by SSH.