Try or Die: Dynamics of Plant Respiration and How to Survive Low Oxygen Conditions.

Fluctuations in oxygen (O 2 ) availability occur as a result of flooding, which is periodically encountered by terrestrial plants. Plant respiration and mitochondrial energy generation rely on O 2 availability. Therefore, decreased O 2 concentrations severely affect mitochondrial function. Low O 2 concentrations (hypoxia) induce cellular stress due to decreased ATP production, depletion of energy reserves and accumulation of metabolic intermediates. In addition, the transition from low to high O 2 in combination with light changes-as experienced during re-oxygenation-leads to the excess formation of reactive oxygen species (ROS). In this review, we will update our current knowledge about the mechanisms enabling plants to adapt to low-O 2 environments, and how to survive re-oxygenation. New insights into the role of mitochondrial retrograde signaling, chromatin modification, as well as moonlighting proteins and mitochondrial alternative electron transport pathways (and their contribution to low O 2 tolerance and survival of re-oxygenation), are presented.