Ethylene as a plant aging modulator

Ethylene is well known as inducer of the final stage of plant aging, senescence. However, aging occurs all through the lifecycle of a plant, and here we define plant aging as the passing of time in a living plant in chronological order. Thus, in this chapter, we explore the role of ethylene in plant aging, starting from seed germination and ending at plant death. Much of the work discussed is based on research performed with the monocarpic model plant Arabidopsis thaliana, while we aimed to venture away from this small plant where possible. We found that ethylene-signaling peaks during germination, around the floral transition and during senescence. This is consistent with prominent evidence of ethylene’s role in these processes. Ethylene interacts with various other phytohormones, notably with abscisic acid, jasmonic acid, and cytokinin, in different ways and throughout aging to exert its effects. Plants can finish their lifecycle in the absence of ethylene signaling, and our analysis of current literature suggests that although ethylene is not critical, it is an important modulator of aging in plants.