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
Molecular, physiological and environmental regulation of toxic prussic acid levels (cyanogenesis) in forage sorghum. Forage sorghum is grown widely in dry, tropical areas of Australia. The leaves contain dhurrin, a natural defence product that liberates prussic acid (cyanide) when leaf tissue is disrupted (eg when chewed). The problem is that young plants or those experiencing drought are highly toxic, resulting in financial loss through reduced nutritive value, livestock loss and wasted feed. U ....Molecular, physiological and environmental regulation of toxic prussic acid levels (cyanogenesis) in forage sorghum. Forage sorghum is grown widely in dry, tropical areas of Australia. The leaves contain dhurrin, a natural defence product that liberates prussic acid (cyanide) when leaf tissue is disrupted (eg when chewed). The problem is that young plants or those experiencing drought are highly toxic, resulting in financial loss through reduced nutritive value, livestock loss and wasted feed. Using new, non-GM technology we will identify novel genetically altered sorghum lines with negligible prussic acid. Lines with enhanced levels could be used as soil biofumigants. Breeders can use this germplasm to develop varieties tailored for increasingly dry Australian conditions. The new varieties with controlled dhurrin content will be suitable for export.Read moreRead less
Dissecting the Indigo Pathway in Natural Indigo Producing Plants: Intricate Pathway Engineering for the Generation of Blue-Fibre Cotton. Australian cotton growers must maintain a sustained competitive advantage in the future to compete within the global cotton market by commanding higher margins for specialty cotton lint over and above current revenues. Development, via biotechnology, of naturally-colored, 'blue' lint cottons is the technical goal, where novel environmentally-benign textile prod ....Dissecting the Indigo Pathway in Natural Indigo Producing Plants: Intricate Pathway Engineering for the Generation of Blue-Fibre Cotton. Australian cotton growers must maintain a sustained competitive advantage in the future to compete within the global cotton market by commanding higher margins for specialty cotton lint over and above current revenues. Development, via biotechnology, of naturally-colored, 'blue' lint cottons is the technical goal, where novel environmentally-benign textile products could be produced without the use of toxic synthetic dyes or caustic dyeing processes. Success will provide a unique opportunity to re-establish an Australian cotton/textile industry by allowing direct participation in the development, branding and marketing of novel Australian textile products, generating potential revenue upwards of $10B/year. Read moreRead less
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
Integrated genetic regulation of photomorphogenesis in Pisum. This project will use a molecular genetic approach in garden pea to investigate the roles of photoreceptors that mediate developmental responses to light. It will define gene families encoding phytochrome, cryptochrome and phototropin photoreceptors, characterise photoreceptor gene expression, and identify mutants with impaired response to light. The mutants will be used in molecular, physiological and biochemical studies to examine h ....Integrated genetic regulation of photomorphogenesis in Pisum. This project will use a molecular genetic approach in garden pea to investigate the roles of photoreceptors that mediate developmental responses to light. It will define gene families encoding phytochrome, cryptochrome and phototropin photoreceptors, characterise photoreceptor gene expression, and identify mutants with impaired response to light. The mutants will be used in molecular, physiological and biochemical studies to examine how photoreceptors control and co-ordinate development throughout the plant via effects on plant hormone synthesis and response. Results from the project will be of practical importance in manipulating key aspects of plant growth to better suit particular environmental and agronomic objectives.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
The role of plant hormones in arbuscular mycorrhizal symbiosis. The vast majority of plant species can form a beneficial symbiosis with specialised soil fungi, an association that can enhance the uptake of nutrients from the soil, improve tolerance to drought and disease and minimise soil erosion. An understanding of how plants establish and regulate this important symbiosis has the potential to contribute to the development of productive and sustainable farming systems by making efficient use o ....The role of plant hormones in arbuscular mycorrhizal symbiosis. The vast majority of plant species can form a beneficial symbiosis with specialised soil fungi, an association that can enhance the uptake of nutrients from the soil, improve tolerance to drought and disease and minimise soil erosion. An understanding of how plants establish and regulate this important symbiosis has the potential to contribute to the development of productive and sustainable farming systems by making efficient use of the limited water resources, reducing soil erosion, reducing reliance on pesticides and fertilisers and producing more nutritious fruits, vegetables and grains.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