Abstract
Some processes of programmed cell death (PCD) are associated with petal senescence, but little is known about the induction mechanism. In senescing petals of Japanese morning glory (Ipomoea nil), we have detected PCD-specific changes in DNA and nuclei. We have also estimated that those genes inducing petal senescence were expressed between anthesis and just before wilting on the basis of the effect of RNA synthesis inhibitor on senescence. In the present study, we isolated 23 genes that changed their expression during the estimated period using cDNA subtraction and differential screening. We also confirmed mRNA levels of isolated genes in the petals using real-time RT-PCR. The levels of mRNA from unknown genes (3), senescence-related homologues (5), and also cell death-related homologues (4) showed remarkable changes in the petals during induction period of senescence. This suggests that PCD process may be also associated with the induction of petal senescence in Ipomoea nil.
