PHA production, from bacteria to plants.

Abstract The genes encoding the polyhydroxyalkanoate (PHA) biosynthetic pathway in Ralstonia eutropha (3-ketothiolase, phaA or bktB ; acetoacetyl-CoA reductase, phaB ; and PHA synthase, phaC ) were engineered for plant plastid targeting and expressed using leaf (e35S) or seed-specific (7s or lesquerella hydroxylase) promoters in Arabidopsis and Brassica . PHA yields in homozygous transformants were 12–13% of the dry mass in homozygous Arabidopsis plants and approximately 7% of the seed weight in seeds from heterozygous canola plants. When a threonine deaminase was expressed in addition to bktB , phaB and phaC , a copolyester of 3-hydroxybutyrate and 3-hydroxyvalerate was produced in both Arabidopsis and Brassica .