Synthesis of a novel class of polyhydroxyalkanoates in Arabidopsis peroxisomes, and their use in monitoring short-chain-length intermediates of β-oxidation

The poly\(R)-3-hydroxyalkanoate\ (PHA) synthase gene (phaC(AC)) of Aeromonas caviae FA440 was modified by adding a peroxisome targeting signal encoding the last 10 amino acids at the carboxyl-terminal of spinach glycolate oxidase. The modified gene was introduced into Arabidopsis thaliana plants by Agrobacterium-mediated transformation. The transgenic Arabidopsis plant expressed the introduced gene and its protein, and it accumulated PHA in its tissues. Gas chromatography-mass spectrometry analysis demonstrated the accumulation of a novel type of PHA, poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate). This strongly suggests that short-chain-length (R)-3-hydroxyacyl-CoAs were generated from intermediates of peroxisomal P-oxidation. It was revealed by using this transgenic plant that TWeen-20 can activate peroxisomal P-oxidation of short-chain-length fatty acids.