Molecular Mechanisms of Petal Senescence in Ornamental Plants

Flower longevity is one of the most important traits for ornamental plants. Ethylene plays a crucial role in petal senescence in many plant species. Genes involved in ethylene biosynthesis, ethylene perception, and its signal transduction have been identified in several ornamental plants. Genetic modification of ethylene signaling genes has successfully improved flower longevity in several plant species. In contrast, regulatory mechanisms of petal senescence in flowers that show ethylene-independent senescence remain largely unknown. Japanese morning glory (Ipomoea nil) is a proposed model plant for ethylene-independent petal senescence, and an important role of autophagy in petal senescence has been highlighted in this plant. This review focused on our recent findings on ethylene signaling and our attempts to identify factors regulating ethylene-independent petal senescence.