The plant homologue of the defender against apoptotic death gene is down-regulated during senescence of flower petals.

Petal senescence is an example of a highly reproducible cell death programme. In this programme, DNA is fragmented internucleosomally and cells with condensed nuclei containing an increased number of 5' ends can be detected with the TUNEL technique. The pea homologue of defender against apoptotic death (dad), a gene described to suppress endogenous programmed cell death in Caenorhabditis elegans and mammals was isolated. Expression studies show that dad declines dramatically upon flower anthesis disappearing in senescent petals, and is down-regulated by the plant hormone ethylene.