大野, 豊 ,
長谷, 純宏 ,
Oxalate is a simple dicarboxylic acid, which is accumulated in leaves of various plant species. Excess uptake of oxalate rich leaves causes mineral lacking and urinary syndrome to livestock. In plants, the oxalate is a useful metabolite for defense against predators, detoxification of metallic ions such as aluminium, and a source of hydrogen peroxide which plays an important role as a signal molecule in wounded or aging leaves. For the oxalate synthesis, three pathways (glycolate, isocitrate, and ascorbate pathway) have been reported in plants. However, it remains unknown which pathway contributes to oxalate accumulation in rice. In the previous study, we showed that isocitrate lyase (ICL) is an important enzyme involved in oxalate synthesis in oxalate rich weed Rumex obtusifolius. In this research, we focused on the role of ICL in the rice oxalate synthesis. Treatment of itaconate (an inhibitor of ICL) to rice seedlings showed that ICL was also involved in the oxalate accumulation in rice. Metabolome analysis of leaves arised from ion beam-irradiated rice seeds revealed that carbon flow via isocitrate pathway affected oxalate accumulation.