Detoxifying aluminium with buckwheat

Aluminium toxicity is a major problem limiting crop production in acid soils, which account for around 40% of the world's arable land1. Some plants have developed strategies to avoid or tolerate aluminium, including buckwheat (Fagopyrum esculentum Moench cv. Jianxi), which has a high resistance to aluminium, but the mechanism responsible for resistance is not known. We have found that the aluminium-resistant Juanxi cultivar of buckwheat secretes oxalic acid from its roots specifically and quickly in response to aluminium stress. Further, aluminium accumulates in the leaf cells in a non-toxic Al-oxalate complex with a 1:3 ratio of aluminium to oxalic acid.