Regulation of wound ethylene synthesis in plants

Abstract

Ethylene is produced by plants at specific stages of their life cycle and is involved in the regulation of many developmental processes, such as fruit ripening, flower fading, leaf abscission, growth in aquatic plants and initiation of flowering in bromeliads^1,2. Ethylene is also formed when plants are subjected to stress by, for example, wounding, noxious chemicals, drought or waterlogging^1–3. In both cases the biosynthetic pathway begins with methionine ^1–5. It proceeds to ethylene by way of S-adenosylmethionine (SAM) and 1-aminocyclopropane-1-carboxylic acid (ACC), a recently discovered intermediate^6,7, in ripening fruit^7,8 and auxin-treated pea stem sections^9,10. We now report that wound-induced ethylene synthesis also proceeds by way of ACC and that it is regulated at the level of the ACC-forming enzyme (ACC synthase). Wounding of pericarp tissue of tomato fruit (Lycopersicon esculentum Mill.) results in rapid enhancement of the activity of ACC synthase and, consequently, in a greatly increased rate of ACC synthesis.