title: Peroxisomal polyhydroxyalkanoate biosynthesis is a promising strategy for bioplastic production in high biomass crops.
abstract: Polyhydroxyalkanoates (PHAs) are bacterial carbon storage polymers with diverse plastic-like properties. PHA biosynthesis in transgenic plants is being developed as a way to reduce the cost and increase the sustainability of industrial PHA production. The homopolymer polyhydroxybutyrate (PHB) is the simplest form of these biodegradable polyesters. Plant peroxisomes contain the substrate molecules and necessary reducing power for PHB biosynthesis, but peroxisomal PHB production has not been explored in whole soil-grown transgenic plants to date. We generated transgenic sugarcane (Saccharum sp.) with the three-enzyme Ralstonia eutropha PHA biosynthetic pathway targeted to peroxisomes. We also introduced the pathway into Arabidopsis thaliana, as a model system for studying and manipulating peroxisomal PHB production. PHB, at levels up to 1.6%-1.8% dry weight, accumulated in sugarcane leaves and A. thaliana seedlings, respectively. In sugarcane, PHB accumulated throughout most leaf cell types in both peroxisomes and vacuoles. A small percentage of total polymer was also identified as the copolymer poly (3-hydroxybutyrate-co-3-hydroxyvalerate) in both plant species. No obvious deleterious effect was observed on plant growth because of peroxisomal PHA biosynthesis at these levels. This study highlights how using peroxisomal metabolism for PHA biosynthesis could significantly contribute to reaching commercial production levels of PHAs in crop plants.
authors: The University of Queensland, School of Biological Science, Brisbane, Qld, Australia.
authors: Kimberley
authors: K
authors: Tilbrook
authors: Leigh
authors: L
authors: Gebbie
authors: Peer M
authors: PM
authors: Schenk
authors: Yves
authors: Y
authors: Poirier
authors: Stevens M
authors: SM
authors: Brumbley
mesh_terms: D000102:Acetyl-CoA C-Acyltransferase / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D003001:Cloning, Molecular; D020118:Cupriavidus necator / Q000235:genetics / Q000378:metabolism; D057075:Enzyme Assays; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D020675:Peroxisomes / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D031786:Saccharum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D036226:Seedlings / Q000235:genetics / Q000378:metabolism; D014170:Transformation, Genetic; D014617:Vacuoles / Q000378:metabolism; D003313:Zea mays / Q000235:genetics; D000094122:Polyhydroxybutyrates
chemical_list: D000102:Acetyl-CoA C-Acyltransferase; D011091:Polyesters; D054813:Polyhydroxyalkanoates; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates