Abstract:NADPH-dependent acetoacetyl-CoA reductase gene (phbB) and poly-β-hydroxybu-tyrate (PHB) synthase gene (phbC) for biosynthesis of PHB were amplified and cloned from chromosomal DNA of Alcaligenes eutrophus H16 using PCR. The restriction maps and sequencing results show that both phbB and phbC have been cloned. It was found that the two genes cloned were highly homologous in DNA sequences to those being reported abroad. By DNA processing, the authors have constructed three tuber-specific plant expression vectors: pPSAGB (containing phbB), pBIBGC (containing phbC) and pPSAGCB (containing both phbB and phbC).