Generation of poly-β-hydroxybutyrate from externally provided acetate in rice root

► Externally provided 14C-acetate was rapidly converted to PHB in rice and wheat. ► In rice root provided 14C-acetate, an unknown organic acid (X) was detected. ► The X was extracted by alkaline solution, and matched authentic β-hydroxybutyrate. ► The original form of this X was identified as poly-β-hydroxybutyrate (PHB). ► PHB might have important role in organic acid metabolism in higher plants.