Proteornic analysis of pollination-induced senescence in Petunia flowers

Senescence represents the last stage of flower development, ultimately culminating in the death of the petals. The senescence program is regulated by coordinated changes in gene and protein expression, and the later stages of senescence share many characteristics of programmed cell death. In some flowers, like petunias, petal senescence is associated with increased ethylene production and wilting is accelerated by treatment with ethylene. We have recently taken a proteomic approach to profile protein changes during the pollination-induced senescence of petunia petals. Two-dimensional electrophoresis comparing unpollinated corollas at 24 h, 48 h, and 72 h after flower opening to corollas at 24 h, 48 h, and 72 h after pollination has identified a number of proteins that are up- or down-regulated during corolla senescence. Electrospray ionization-tandem mass spectrometry (ESI-MS/MS) has been used to determine the identity of these differentially expressed proteins. A total of 143 proteins have been sequenced and greater than 85% have been identified. The function of the up-regulated proteins is being confirmed using virus-induced gene silencing (VIGS).