Expression of poly-3-(R)-hydroxyalkanoate (PHA) polymerase and acyl-CoA-transacylase in plastids of transgenic potato leads to the synthesis of a hydrophobic polymer, presumably medium-chain-length PHAs

• Published in: Planta 2005, Vol.220 (3), p.455-464
• Main Authors: Romano, A, Plas, L.H.W. van der, Witholt, B, Eggink, G, Mooibroek, H
• Format: Article
• Language: English
• Subjects: acyl-coenzyme A-transacylase; acyltransferases; Acyltransferases - metabolism; Bacterial Proteins - metabolism; beta-oxidation; Biological and medical sciences; Biosynthesis; biosynthetic-pathway; Complementary DNA; Fatty acids; fluorescent pseudomonads; functional expression; Fundamental and applied biological sciences. Psychology; Gas chromatography; Gene Expression; Genes, Bacterial; genetic transformation; Molecular and cellular biology; Molecular genetics; molecular sequence data; Monomers; nonrelated carbon-sources; nucleotide sequences; particle bombardment; Phenotype; phenotypic variation; plant morphology; plant proteins; Plants; Plants, Genetically Modified - metabolism; Plastids; Plastids - metabolism; poly-3-(R)-hydroxyalkanoate polymerase; Polyhydroxyalkanoates; polyhydroxyalkanoic acid; Polymerase chain reaction; Polymers; Potatoes; Pseudomonas oleovorans - genetics; Pseudomonas putida - genetics; pseudomonas-aeruginosa; Research universities; Solanum tuberosum; Solanum tuberosum - genetics; Solanum tuberosum - metabolism; Transgenic plants; unsaturated fatty-acids; Vegetables
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-004-1349-8

Medium-chain-length poly-3-(R)-hydroxyalkanoates (mcl-PHAs) belong to the group of microbial polyesters. The minimum gene-set for the accumulation of mcl-PHAs from de novo fatty acid biosynthesis has been identified in prokaryotes B. Rehm et al. (1998) J. Biol Chem 273:24044-24051 as consisting of the Pha-C1 polymerase and the ACP-CoA-transacylase. In this paper, the synthesis of mcl-PHAs has been attempted in transgenic potato (Solanum tuberosum L.) using the same set of genes that were introduced into potato by particle bombardment. Polymer contents of transgenic lines were analysed by gas chromatography and by a new simple method employing a size-exclusion filter column. The expression of the Pha-C1 polymerase and the ACP-CoA-transacylase in the plastids of transgenic potato led to the synthesis of a hydrophobic polymer composed of mcl-hydroxy-fatty acids with carbon chain lengths ranging from C-6 to C-12 in leaves of the selected transgenic lines. We strongly suggest that the polymer observed consists of mcl-PHAs and that this report establishes for the first time a possible route for the production of mcl-PHAs from de novo fatty acid biosynthesis in plants.