Metabolic strategies in hypoxic plants.

Complex multicellular organisms have evolved in an oxygen-enriched atmosphere. Oxygen is therefore essential for all aerobic organisms, including plants, for energy production through cellular respiration. However, plants can experience hypoxia following extreme flooding events and also under aerated conditions in proliferative organs or tissues characterized by high oxygen consumption. When oxygen availability is compromised, plants adopt different strategies to cope with hypoxia and limited aeration. A common feature among different plant species is the activation of an anaerobic fermentative metabolism to provide ATP to maintain cellular homeostasis under hypoxia. Fermentation also requires many sugar substrates, which is not always feasible, and alternative metabolic strategies are thus needed. Recent findings have also shown that the hypoxic metabolism is also active in specific organs or tissues of the plant under aerated conditions. Here, we describe the regulatory mechanisms that control the metabolic strategies of plants and how they enable them to thrive despite challenging conditions. A comprehensive mechanistic understanding of the genetic and physiological components underlying hypoxic metabolism should help to provide opportunities to improve plant resilience under the current climate change scenario.