Plant responses to hypoxia - is survival a balancing act?

Molecular-oxygen deficiency leads to altered cellular metabolism and can dramatically reduce crop productivity. Plants that survive or succumb to transient submergence differ in the timing and duration of carbohydrate consumption and anaerobic metabolism. The increased production of alcohol dehydrogenase, which is required for anaerobic fermentation, paradoxically involves the formation of a reactive oxygen species. Activation of a Rho of plant (Rop) G-protein results in an increase in hydrogen peroxide that correlates with elevation of alcohol dehydrogenase expression. Tolerance of oxygen deficiency requires both activation and inactivation of the G-protein by negative-feedback regulation. We propose that the magnitude and the duration of the signaling can provide tolerance of oxygen deficiency through management of carbohydrate consumption and avoidance of oxidative stress.