A homolog of the defender against apoptotic death gene (DAD1) in senescing gladiolus petals is down-regulated prior to the onset of programmed cell death.

We isolated a homolog of the potential anti-apoptotic gene, defender against apoptotic death (DAD1) from gladiolus petals as full-length cDNA (GlDAD1), and investigated the relationship between its expression and the execution processes of programmed cell death (PCD) in senescing petals. RNA gel blotting showed that GlDAD1 expression in petals was drastically reduced, considerably before the first visible senescence symptom (petal wilting). A few days after down-regulation GlDAD1 expression, DNA and nuclear fragmentation were observed, both specific for the execution phase of PCD.