Averting a sweet demise: sugars change the transcriptional hypoxia response in maize roots

Low oxygen (hypoxic) conditions can occur in hypoxic niches during normal plant development or as a result of plant submergence. Hypoxia limits mitochondrial respiration and causes a serious drop in available energy. To ensure cell survival during hypoxia, plants typically switch on alternative energy producing pathways that don’t require oxygen, such as glycolysis and fermentation. However, glycolysis can quickly drain the plant’s carbohydrate reserves, as 1 glucose molecule only yields 2 ATP (compared to 36 ATP through oxidative phosphorylation). Consequently, sugar and hypoxia responses need to be tightly regulated to maintain cellular homeostasis and ensure survival. While several hypoxia responses were shown to be dependent on the plant’s carbohydrate status, little is known about how the plant’s sugar status and signaling interact with the hypoxia response. In this issue of Plant Physiology, Sanclemente et al. (2020) show that glucose levels have several distinct effects on the hypoxia response in maize (Zea mays L.) roots.