Elevated carbon dioxide-induced regulation of ethylene in plants

Climate change-associated rise in atmospheric CO 2 concentration has a wide range of both beneficial and detrimental effects on global food production. In C 3 plants, elevated CO 2 concentrations enhance photosynthesis, growth, yield and abiotic stress tolerance, but reduce nutritional values and plant defense against certain pests and pathogens. Phytohormone ethylene is involved in many biological processes and also mediates responses to CO 2 . Elevated CO 2 has been shown to increase, impede, or have no influence on ethylene production at various phases of plant growth and development. Recent studies have unveiled the importance of ethylene biosynthesis and signaling in elevated CO 2 -induced stress tolerance. Diverse and complex effects of elevated CO 2 on ethylene production, stomatal behavior, photosynthesis and metabolic homeostasis mediate abiotic stress tolerance; whereas suppression of ethylene/jasmonate pathways by elevated CO 2 attenuates plant defense against insect herbivores and necrotrophic fungal pathogens. Furthermore, treatments with high CO 2 concentrations have been found advantageous for postharvest storage of a variety of fresh horticultural products. The senescence-delaying impact of CO 2 is ascribed to its role as an ethylene competitor at the ethylene receptor site and on various metabolic pathways. In this review, we firstly discuss the impacts of high atmospheric CO 2 concentrations on photosynthesis, stomatal movement, ethylene production and its relationship to plant growth, development, physiology and stress responses. We also expand the discussion to the effect of increased CO 2 levels on commercially important plant organs, such as fruit, vegetables and flowers concerning its advantages and disadvantages in postharvest management. As atmospheric CO 2 concentrations will further rise, it is far more important than ever to know how plants react to high CO 2 concentrations using cutting-edge molecular technology. • High CO 2 (eCO 2 ) has both beneficial and detrimental effects on crop production. • Phytohormone ethylene mediates plant responses to eCO 2 in many biological processes. • Ethylene biosynthesis and signaling also alters stress tolerance under eCO 2 conditions. • Senescence-delaying impact of CO 2 is linked to ethylene metabolism and signaling. • Ethylene management by eCO 2 is advantageous for postharvest management of crops.