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
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
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
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
Genetic and Hormonal Regulation of Plant Growth. Leguminous plants make a substantial contribution to the Australian economy. To ensure future growth, we need to know more about how legume development is regulated. Genetic mutants, typically affecting the growth-promoting gibberellin plant hormones, played a key role in the green revolution, which transformed agriculture world-wide. Recent results show that gibberellin acts in concert with another hormone, auxin. We will generate new auxin-relat ....Genetic and Hormonal Regulation of Plant Growth. Leguminous plants make a substantial contribution to the Australian economy. To ensure future growth, we need to know more about how legume development is regulated. Genetic mutants, typically affecting the growth-promoting gibberellin plant hormones, played a key role in the green revolution, which transformed agriculture world-wide. Recent results show that gibberellin acts in concert with another hormone, auxin. We will generate new auxin-related mutants that will help us to understand how auxin and auxin-mediated interactions affect crop architecture and performance. Further benefit will accrue from training of students in state-of-the-art techniques, and the generation of new germplasm for use by other researchers and plant breeders. Read moreRead less
Genetic and Hormonal Interactions Controlling Shoot Growth. This project will determine how plant growth is regulated at the genetic, biochemical, and physiological levels, and how plant hormones provide key links between the genotype and overall phenotype (phenome). The work uses peas as a model because of the wealth of mutants available and the suitability of the species for physiological and biochemical studies. Our results will allow comparison of development in the caulescent pea plant wi ....Genetic and Hormonal Interactions Controlling Shoot Growth. This project will determine how plant growth is regulated at the genetic, biochemical, and physiological levels, and how plant hormones provide key links between the genotype and overall phenotype (phenome). The work uses peas as a model because of the wealth of mutants available and the suitability of the species for physiological and biochemical studies. Our results will allow comparison of development in the caulescent pea plant with other model species with different growth habits, such as Arabidopsis. The project is significant because it will enable shoot growth to be modified either genetically or chemically to meet particular agronomic objectives.Read moreRead less
Development and regulation of thermogenesis in thermoregulating flowers. Flowers of certain primitive plants produce enough heat to raise their temperatures up to 40 C above the air, and regulate it at a nearly constant level. Like warm-blooded mammals, the flowers increase heat production as environmental temperature falls. However, they thermoregulate on a cellular level, unlike mammals with their complex nervous system. We aim to elucidate the mechanisms involved in regulation of heat-prod ....Development and regulation of thermogenesis in thermoregulating flowers. Flowers of certain primitive plants produce enough heat to raise their temperatures up to 40 C above the air, and regulate it at a nearly constant level. Like warm-blooded mammals, the flowers increase heat production as environmental temperature falls. However, they thermoregulate on a cellular level, unlike mammals with their complex nervous system. We aim to elucidate the mechanisms involved in regulation of heat-production, with molecular, biochemical and stable isotope techniques. We will investigate spatial and temporal patterns of gene expression and activity of putative regulatory enzymes. The results will have implications for human physiology and agriculture.Read moreRead less
Brassinosteroids and Plant Development. Brassinosteroids are steroid hormones, which are essential for normal plant growth and development. This project will address fundamental questions regarding the biology of these substances. The work uses pea as a model species because of its suitability for physiological, biochemical and genetic studies. The results obtained will substantially increase our knowledge of the way in which these substances regulate plant growth. This is significant as it will ....Brassinosteroids and Plant Development. Brassinosteroids are steroid hormones, which are essential for normal plant growth and development. This project will address fundamental questions regarding the biology of these substances. The work uses pea as a model species because of its suitability for physiological, biochemical and genetic studies. The results obtained will substantially increase our knowledge of the way in which these substances regulate plant growth. This is significant as it will ultimately allow plant growth to be modified either genetically or chemically, to meet particular agronomic objectives.Read moreRead less