Controlling the rate of transcription and translation of Rubisco transgenes effectively in higher-plant plastids. Genetic transformation of the circular genome of the plastids provides a containable means for modifying plant growth by manipulating photosynthesis. Although the transformation mechanism is precise, predicting the level of foreign gene expression is difficult because the amounts of messenger RNA and protein produced by foreign genes in plastids varies widely, even when the protein a ....Controlling the rate of transcription and translation of Rubisco transgenes effectively in higher-plant plastids. Genetic transformation of the circular genome of the plastids provides a containable means for modifying plant growth by manipulating photosynthesis. Although the transformation mechanism is precise, predicting the level of foreign gene expression is difficult because the amounts of messenger RNA and protein produced by foreign genes in plastids varies widely, even when the protein assembles without difficulty. This project will devise strategies for controlling this variability that will facilitate attempts to exploit plastid transformation for transplanting better versions of the photosynthetic CO2-fixing enzyme, Rubisco, into plants to improve their growth efficiency in terms of water, fertiliser and light use.Read moreRead less
Defining New Building Blocks for the Construction of Artificial Genetic Circuits. By characterising the components of a natural genetic switch, we will make available a set of well defined genetic building blocks for construction of rationally designed biological circuits. The ability to build such circuits would have significant economic benefit in areas such as metabolic engineering, to improve the efficiency of production of natural compounds from micro-organisms, and in biomedicine, for the ....Defining New Building Blocks for the Construction of Artificial Genetic Circuits. By characterising the components of a natural genetic switch, we will make available a set of well defined genetic building blocks for construction of rationally designed biological circuits. The ability to build such circuits would have significant economic benefit in areas such as metabolic engineering, to improve the efficiency of production of natural compounds from micro-organisms, and in biomedicine, for the controlled release of therapeutic compounds. The involvement of Honours and Ph.D students in this project will expose the next generation of Australian scientists to this emerging discipline. International collaboration leading to publications in high impact scientific journals will enhance Australia's scientific reputation.Read moreRead less
Practical strategies for engineering the CO2-fixing enzyme, Rubisco, whose subunits are encoded in different subcellular compartments. My recent replacement of the plant CO2-fixing enzyme, Rubisco, with a less efficient bacterial version, with a single type of subunit encoded by a single gene, demonstrated the feasibility of replacing Rubisco. This encourages ongoing attempts to replace plant Rubisco with more efficient versions that would allow the plants to grow with less water, fertiliser or ....Practical strategies for engineering the CO2-fixing enzyme, Rubisco, whose subunits are encoded in different subcellular compartments. My recent replacement of the plant CO2-fixing enzyme, Rubisco, with a less efficient bacterial version, with a single type of subunit encoded by a single gene, demonstrated the feasibility of replacing Rubisco. This encourages ongoing attempts to replace plant Rubisco with more efficient versions that would allow the plants to grow with less water, fertiliser or light. The most efficient Rubiscos are more complex, with two different types of subunits which, in plants, are encoded in different subcellular compartments (nucleus and plastid). This proposal addresses the challenges associated with complementary engineering both genomes to substitute foreign Rubiscos into higher-plant chloroplasts.Read moreRead less
IMPROVING NITROGEN USE EFFICIENCY IN CROP PLANTS: ROLE OF THE AMMONIUM TRANSPORT FAMILY AMT. Improving nitrogen use efficiency in crop plants will reduce the use of environmentally damaging nitrogen fertilisers that threaten through leaching the sustainability of Australia's agricultural sector and local water ecosystems. Plants contain genes that encode transport proteins required for the uptake of nitrogen (ammonium and nitrate) from the soil. We will identify the in planta activity of the A ....IMPROVING NITROGEN USE EFFICIENCY IN CROP PLANTS: ROLE OF THE AMMONIUM TRANSPORT FAMILY AMT. Improving nitrogen use efficiency in crop plants will reduce the use of environmentally damaging nitrogen fertilisers that threaten through leaching the sustainability of Australia's agricultural sector and local water ecosystems. Plants contain genes that encode transport proteins required for the uptake of nitrogen (ammonium and nitrate) from the soil. We will identify the in planta activity of the AMT family of ammonium transporters and associated signalling pathways which control the uptake and assimilation of ammonium in plants. This project will confirm the mechanisms involved in ammonium uptake from the soil and lead to the development of ammonium-nitrogen efficient crop plants.Read moreRead less
Biosynthesis of nonribosomal peptide toxins in cyanobacteria: A functional characterisation of microcystin synthetase. Microcystins are potent toxins and tumour promoters produced by cyanobacteria associated with blue-green algal blooms. This non-ribosomal peptide is produced by microcystin synthetase, a unique enzyme complex comprised of peptide synthetases, polyketide synthases, and integrated accessory enzymes. We have identified and characterised the extensive gene cluster encoding this enzy ....Biosynthesis of nonribosomal peptide toxins in cyanobacteria: A functional characterisation of microcystin synthetase. Microcystins are potent toxins and tumour promoters produced by cyanobacteria associated with blue-green algal blooms. This non-ribosomal peptide is produced by microcystin synthetase, a unique enzyme complex comprised of peptide synthetases, polyketide synthases, and integrated accessory enzymes. We have identified and characterised the extensive gene cluster encoding this enzyme. This project describes the biochemical characterisation of specific enzyme activities within microcystin synthetase and how they determine the final structure and toxicity of the many forms of microcystin. Interactions between this enzyme complex and its substrate amino acids will provide information for the genetic engineering of this and similar natural products.Read moreRead less
Targeted bioengineering and systems biology for solar powered hydrogen production in green algal cells. The development of clean fuels to combat climate change and protect against oil price shocks, is an urgent challenge facing our society. Fuels make up ~67% of the energy market, yet most low-CO2 emissions technologies (e.g. nuclear and clean-coal-technology) target the electricity market. In contrast the Solar Bio-H2 process uses algal photobioreactors to drive solar-powered H2 fuel production ....Targeted bioengineering and systems biology for solar powered hydrogen production in green algal cells. The development of clean fuels to combat climate change and protect against oil price shocks, is an urgent challenge facing our society. Fuels make up ~67% of the energy market, yet most low-CO2 emissions technologies (e.g. nuclear and clean-coal-technology) target the electricity market. In contrast the Solar Bio-H2 process uses algal photobioreactors to drive solar-powered H2 fuel production from water (ultimately sea water, facilitating desalination). This project aims to improve the efficiency of the process towards economical levels. The Solar Bio-H2 process reduces water requirements for biofuel production. Locating bioreactors on non-arable land also eliminates competition between biofuel and food production.Read moreRead less