The current knowledge of the molecular mechanisms for Mg transport in plants is very limited, with only three publications reporting a molecular basis for Mg transport in plants. However, the importance of Mg to plants has been well described, and physiological and ecophysiological studies about the effects of Mg are numerous. This section will summarise the knowledge of a gene family identified in plants that is distantly related to CorA. Another gene, a Mg/H exchanger (AtMHX), unrelated to this gene family and to CorA has also been identified, is localised to the vacuolar membrane, and will be described last.