Abstract
Polygonaceous plants contain high concentrations of oxalate. Excess uptake of this substance is toxic to animals. In plants, oxalate plays an important role as a source of hydrogen peroxide, which may act as defense molecules. Furthermore, some plants secrete oxalate to the rhizosphere, which could detoxify metallic ions.
Oxalate is known to be synthesized through several pathways. However, detailed studies concerning biochemical and molecular analysis of the pathways have not been presented. In this investigation, we analyzed the biochemical regulation of oxalate accumulation in polygonaceous plants. Measurement of metabolites by CE-MS indicated that oxalate levels were quite different among plant species. Enzyme assays demonstrated that the lactate dehydrogenase showed highest activity among other enzymes. The metabolic significance of such pathway in oxalate synthesis in polygonaceous plants will be presented.
