Abstract: Transgenic plants, plant material, plant cells, and genetic constructs for synthesis of biopolymers, for example polyhydroxyalkanoates (“PHA”) are provided. In one embodiment, the transgenic plants synthesize polyhydroxybutyrate (“PHB”). In one embodiment the transgenic plant encodes siRNA for one or more of the genes encoding enzymes for producing PHA. In a more preferred embodiment, the siRNA expression is under the control of an inducible regulatory element. In another embodiment, the transgenic plant contains transgenes that encode expression enzymes that will degrade the polymer. In a preferred embodiment, the expression of these enzymes is under the control of a germination specific, inducible, or minimal promoter. In another embodiment, the transgenic plant contains transgenes encoding enzymes that increase carbon flow for polymer synthesis. In a preferred embodiment, these transgenes encode enzymes that increase carbon flow in the Calvin Cycle.

Abstract: Transgenic plants that produce high levels of polyhydroxybutyrate and methods of producing them are provided. In a preferred embodiment the transgenic plants are produced using plastid transformation technologies and utilize genes which are codon optimized. Stably transformed plants able to produce greater than 10% dwt PHS in tissues are also provided.

Abstract: Transgenic plants, plant material, plant cells, and genetic constructs for synthesis of biopolymers, for example polyhydroxyalkanoates (“PHA”) are provided. In one embodiment, the transgenic plants synthesize polyhydroxybutyrate (“PHB”). In one embodiment the transgenic plant encodes siRNA for one or more of the genes encoding enzymes for producing PHA. In a more preferred embodiment, the siRNA expression is under the control of an inducible regulatory element. In another embodiment, the transgenic plant contains transgenes that encode expression enzymes that will degrade the polymer. In a preferred embodiment, the expression of these enzymes is under the control of a germination specific, inducible, or minimal promoter. In another embodiment, the transgenic plant contains transgenes encoding enzymes that increase carbon flow for polymer synthesis. In a preferred embodiment, these transgenes encode enzymes that increase carbon flow in the Calvin Cycle.

Abstract: Transgenic plants, transgenic plant material, and transgenic plant cells for the improved synthesis of polyhydroxyalkanoates, preferably poly(3-hydroxybutyrate) (also referred to as PHB), have been developed. In one embodiment, carbon flow is modulated to increase production of PHB. Preferred plants that can be genetically engineered to produce PHB include plants that produce a large amount of lignocellulosic biomass that can be converted into biofuels, such as switchgrass, Miscanthus, Sorghum, sugarcane, millets, Napier grass and other forage and turf grasses. An exemplary plant that can be genetically engineered to produce PHB and produces lignocellulosic biomass is switchgrass, Panicum virgatum L. A preferred cultivar of switchgrass is Alamo. Other suitable cultivars of switchgrass include, but are not limited to, Blackwell, Kanlow, Nebraska 28, Pathfinder, Cave-in-Rock, Shelter and Trailblazer.

Abstract: Transgenic plants and methods of culturing them using sorbitol as a sole carbon source are provided. One embodiment provides a method and system for positively selecting transgenic plants carrying and expressing a gene of interest. The transgenic plants are engineered to express sorbitol dehydrogenase in an amount effective to allow the transgenic plant to grow using sorbitol as the sole carbon source. In a preferred embodiment, the plant to be transformed does not have endogenous sorbitol dehydrogenase activity. Representative plants that can be transformed, include but are not limited to members of the Brassica family, industrial oilseeds, Arabidopsis thaliana, algae, soybean, cottonseed, sunflower, palm, coconut, rice, safflower, peanut, mustards, silage corn, alfalfa, switchgrass, miscanthus, sorghum, tobacco, sugarcane and flax.

Abstract: Transgenic plants that produce high levels of polyhydroxybutyrate and methods of producing them are provided. In a preferred embodiment the transgenic plants are produced using plastid transformation technologies and utilize genes which are codon optimized. Stably transformed plants able to produce greater than 10% dwt PHS in tissues are also provided.