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
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
Enhancing plant photosynthesis by engineering the carbon dioxide (CO2)-fixing enzyme Rubisco. Improving the ability of crops to use water, sunlight and fertiliser more efficiently would have economic benefits for Australia and ease the environmental impacts associated with agricultural practices. Photosynthesis research has confirmed that such improvements are theoretically possible by enhancing the efficiency of the protein, Rubisco, which initiates the conversion of carbon dioxide into carbon ....Enhancing plant photosynthesis by engineering the carbon dioxide (CO2)-fixing enzyme Rubisco. Improving the ability of crops to use water, sunlight and fertiliser more efficiently would have economic benefits for Australia and ease the environmental impacts associated with agricultural practices. Photosynthesis research has confirmed that such improvements are theoretically possible by enhancing the efficiency of the protein, Rubisco, which initiates the conversion of carbon dioxide into carbon compounds required for growth. The biotechnological research proposed here uses unique capabilities to improve our understanding of structural features in Rubisco that influence its assembly and functional efficiency in plants. This knowledge will pave the way for transplanting more efficient Rubisco into crops to improve their growth.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
Stomatal function in transgenic plants with altered guard cell metabolism. Guard cells on the surface of leaves control the rate of water loss and CO2 uptake by changing stomatal aperture in response to environmental signals such light, CO2, humidity and water status. Guard cells therefore play a major role in determining plant productivity and water use efficiency. This project aims to examine the contribution of guard cell energy and carbon metabolism in mediating stomatal responses to the env ....Stomatal function in transgenic plants with altered guard cell metabolism. Guard cells on the surface of leaves control the rate of water loss and CO2 uptake by changing stomatal aperture in response to environmental signals such light, CO2, humidity and water status. Guard cells therefore play a major role in determining plant productivity and water use efficiency. This project aims to examine the contribution of guard cell energy and carbon metabolism in mediating stomatal responses to the environment in intact plants through the generation and analysis of transgenic plants with altered guard cell function. This will aid in the development of strategies for direct manipulation of stomatal function.Read moreRead less
Sodium homeostasis and the molecular basis for neurotoxin production by bacteria and algae. An understanding of the physiology of saxitoxin-producing microorgansims in response to salt stress is critical for the prevention of toxic blooms and for risk assessment of contaminated water bodies. This is nowhere more relevant than in the depleted and increasingly saline water resources of inland Australia. This project will develop genetic tests to assay for saxitoxin-producers and to monitor toxin p ....Sodium homeostasis and the molecular basis for neurotoxin production by bacteria and algae. An understanding of the physiology of saxitoxin-producing microorgansims in response to salt stress is critical for the prevention of toxic blooms and for risk assessment of contaminated water bodies. This is nowhere more relevant than in the depleted and increasingly saline water resources of inland Australia. This project will develop genetic tests to assay for saxitoxin-producers and to monitor toxin production in response to the environment, representing an easier, more economic and ethical alternative to current tests. The market for this type of predictive test includes environmental, anti-bioterrorism and fishery organisations. These genes will also allow the bioengineering of novel therapeutic drugs based on neuroactive alkaloids.Read moreRead less
Identifying potential barriers to transplanting modified forms of the CO2-fixing enzyme, Rubisco, into plants. Improving the ability of crops to use water, light and fertiliser more efficiently would have economic benefits and ease the environmental impacts associated with agricultural practices. It is thought that such improvements can be made by enhancing the efficiency of the photosynthetic protein, Rubisco, which fixes most of the CO2 in the biosphere. The research proposed here uses unique ....Identifying potential barriers to transplanting modified forms of the CO2-fixing enzyme, Rubisco, into plants. Improving the ability of crops to use water, light and fertiliser more efficiently would have economic benefits and ease the environmental impacts associated with agricultural practices. It is thought that such improvements can be made by enhancing the efficiency of the photosynthetic protein, Rubisco, which fixes most of the CO2 in the biosphere. The research proposed here uses unique Rubisco transplantation capabilities that I have developed to improve our fundamental understanding of how Rubisco is processed and its activity regulated in plants. This will pave the way for our ongoing efforts to engineer and transplant more efficient Rubisco into crops.Read moreRead less
Probing the four photosynthetic membrane protein complexes at work in situ in leaves. This proposal aims at sustainable improvements in plant productivity and photosynthetic adaptation in drastic Australian climates. In photosynthesis, membranes with the four multiprotein complexes use sunlight to make compounds that drive carbon assimilation. Instead of the usual dissection of photosynthetic membranes, this project will develop and refine the applicant's rapid, reliable, non-intrusive technique ....Probing the four photosynthetic membrane protein complexes at work in situ in leaves. This proposal aims at sustainable improvements in plant productivity and photosynthetic adaptation in drastic Australian climates. In photosynthesis, membranes with the four multiprotein complexes use sunlight to make compounds that drive carbon assimilation. Instead of the usual dissection of photosynthetic membranes, this project will develop and refine the applicant's rapid, reliable, non-intrusive techniques to probe the four membrane complexes at work in their native state in leaves. Two portable commercial instruments will potentially emerge from the techniques. This novel non-reductionist approach will identify key limitations to photosynthetic performance under stress, and insights into improvements for primary plant productivity.Read moreRead less
FUNCTIONAL GENOMICS OF PLANT MITOCHONDRIA: THEIR ROLE IN DEVELOPMENT, OXIDATIVE STRESS AND PLANT DEFENSE. Crops encounter many situations in their environment which place them under stress. Reactive oxygen molecules produced in these situations act as messengers to trigger defence mechanisms but also cause cellular damage. Mitochondria are the subcellular compartments involved in energy production and are essential for plant development and growth. However, they also have been implicated in th ....FUNCTIONAL GENOMICS OF PLANT MITOCHONDRIA: THEIR ROLE IN DEVELOPMENT, OXIDATIVE STRESS AND PLANT DEFENSE. Crops encounter many situations in their environment which place them under stress. Reactive oxygen molecules produced in these situations act as messengers to trigger defence mechanisms but also cause cellular damage. Mitochondria are the subcellular compartments involved in energy production and are essential for plant development and growth. However, they also have been implicated in the response of plants to stress and pathogen attack, and in production of reactive oxygen molecules. This proposal seeks to investigate how mitochondria are involved in these processes, using the latest plant genome information. Potential outcomes include crops better able to cope with environmental stress.Read moreRead less
Active bicarbonate transporters from cyanobacteria: physiological properties, genetic regulation, and introduction into plants for crop improvement. An intriguing set of membrane transport proteins that accumulate bicarbonate into marine cyanobacterial cells will be investigated. These proteins support the crucial process of photosynthetic carbon dioxide fixation in marine cyanobacteria (blue-green algae), which are major contributors to global carbon dioxide sequestration and form one of the f ....Active bicarbonate transporters from cyanobacteria: physiological properties, genetic regulation, and introduction into plants for crop improvement. An intriguing set of membrane transport proteins that accumulate bicarbonate into marine cyanobacterial cells will be investigated. These proteins support the crucial process of photosynthetic carbon dioxide fixation in marine cyanobacteria (blue-green algae), which are major contributors to global carbon dioxide sequestration and form one of the foundations of the marine food web. These bicarbonate "transporters" will also be transferred into a model plant system to test whether the efficiency of photosynthesis can be improved, with corresponding gains in the water-use efficiency of these plants. If successful this technology will have profound global implications for improving crop production in semi-arid areas.Read moreRead less