Using the fractionation of hydrogen and carbon isotopes to analyse the mechanisms of the primary processes of photosynthesis. The primary processes of CO2 fixation and reduction in photosynthesis leave their signatures in the isotopic composition of organic matter. Although these signatures are used widely in geochemistry, biology and climatology to infer the dynamics and history of the biosphere, the information they provide about the mechanisms of the processes that produce them has not been e ....Using the fractionation of hydrogen and carbon isotopes to analyse the mechanisms of the primary processes of photosynthesis. The primary processes of CO2 fixation and reduction in photosynthesis leave their signatures in the isotopic composition of organic matter. Although these signatures are used widely in geochemistry, biology and climatology to infer the dynamics and history of the biosphere, the information they provide about the mechanisms of the processes that produce them has not been exploited fully. We propose to map the underlying biochemistry responsible for fractionation of hydrogen isotopes, to assess its ability to indicate the water relations of plants, and to use carbon-isotope discrimination to probe the catalytic chemistry of the CO2-fixing enzyme, Rubisco.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
What is the function of gamma-aminobutyric acid-gated anion channels in plants? The project will identify the molecular basis of gamma-aminobutyric acid (GABA) signalling in plants. This is significant because GABA regulates proteins that release molecules involved in root-soil interactions, growth, and fertilisation. The project's discoveries will allow improvement of these agronomic traits that ultimately determine crop yield.
Molecular and Cellular Characterisations of the Cortical Actin Cytoskeleton in the Plant Arabidopsis thaliana. Plant cells contain extensive arrays of the cytoskeletal protein actin that attach to the plasma membrane and may play important roles in cell elongation through interactions with cortical microtubules. However, the organisation, dynamics and functions of cortical actin remain poorly understood. I will combine cell and molecular approaches to understanding cortical actin in living tissu ....Molecular and Cellular Characterisations of the Cortical Actin Cytoskeleton in the Plant Arabidopsis thaliana. Plant cells contain extensive arrays of the cytoskeletal protein actin that attach to the plasma membrane and may play important roles in cell elongation through interactions with cortical microtubules. However, the organisation, dynamics and functions of cortical actin remain poorly understood. I will combine cell and molecular approaches to understanding cortical actin in living tissue of Arabidopsis, using both wild-type and previously uncharacterised mutants, and will develop a novel mutational screening strategy to isolate mutants disrupted in plasma membrane or microtubule binding. This research will contribute significantly to a greater understanding of how the plant grows and develops.Read moreRead less
Are flavonoids metabolic regulators of plant development? This project will investigate the mechanisms of action of flavonoids, which are abundant and diverse plant products contained in all fruits and vegetables. We have very little knowledge on the range of activities this large class of natural compounds has in plants. This research will investigate the role of flavonoids in regulating plant development to identify flavonoids and their target proteins and genes that could alter plant develo ....Are flavonoids metabolic regulators of plant development? This project will investigate the mechanisms of action of flavonoids, which are abundant and diverse plant products contained in all fruits and vegetables. We have very little knowledge on the range of activities this large class of natural compounds has in plants. This research will investigate the role of flavonoids in regulating plant development to identify flavonoids and their target proteins and genes that could alter plant development in specific ways to create improved crops. This project will also strengthen Australia's expertise in proteomics, an important tool for the advancement of knowledge and application in biotechnology.Read moreRead less
Novel photoprotective mechanisms and functional biodiversity of high light tolerance in the model alga Chlamydomonas. Most plants have limited capacity to avoid high light (HL) stress which commonly accompanies drought and high temperature stress. We will identify novel genes and proteins that underlie diverse mechanisms of photoprotection in unique very high light resistant (VHLR) mutants in the alga Chlamydomonas and develop new tools to screen other plants for these attributes. Depending on p ....Novel photoprotective mechanisms and functional biodiversity of high light tolerance in the model alga Chlamydomonas. Most plants have limited capacity to avoid high light (HL) stress which commonly accompanies drought and high temperature stress. We will identify novel genes and proteins that underlie diverse mechanisms of photoprotection in unique very high light resistant (VHLR) mutants in the alga Chlamydomonas and develop new tools to screen other plants for these attributes. Depending on progress, we expect to express them in the higher plant Arabidopsis as a first step towards utilization of VHLR genes for crop improvement. Understanding the mechanisms conferring HL photoprotection is a research priority in plant sciences and will further strengthen Australia's innovative contributions to the internationally networked Chlamydomonas Genome Project.Read moreRead less
How do nano-molecular carboxysome protein structures function in alpha and beta-cyanobacteria and can we use them for novel reaction compartmentalisation? In blue-green algae, protein nano-structures, known as carboxysomes, act as tiny compartments where carbon dioxide (CO2) can be fixed into simple sugars at high efficiency. This important photosynthetic process forms the basis of global primary productivity on this planet, but most land-based CO2 fixation lacks the efficiency seen in blue-gree ....How do nano-molecular carboxysome protein structures function in alpha and beta-cyanobacteria and can we use them for novel reaction compartmentalisation? In blue-green algae, protein nano-structures, known as carboxysomes, act as tiny compartments where carbon dioxide (CO2) can be fixed into simple sugars at high efficiency. This important photosynthetic process forms the basis of global primary productivity on this planet, but most land-based CO2 fixation lacks the efficiency seen in blue-greens. This research aims to determine how the proteins that make up carboxysomes are 3-dimensionally arranged and how these structures function to enhance rates of CO2 fixation. A more thorough understanding of the carboxysome is likely to have potential applications in industrial nano-technology and improve our understanding of oceanic primary productivity.Read moreRead less
Photosynthetically active bicarbonate transporters from cyanobacteria & their rational redesign for application in engineered crops that use less water. Marine blue-green algae are critical components of global primary productivity and fisheries productivity but CO2 acquisition processes in these organisms are poorly understood. Our aim is to determine the protein structure and regulatory controls present in two classes of cyanobacterial bicarbonate transporters that are required for efficient p ....Photosynthetically active bicarbonate transporters from cyanobacteria & their rational redesign for application in engineered crops that use less water. Marine blue-green algae are critical components of global primary productivity and fisheries productivity but CO2 acquisition processes in these organisms are poorly understood. Our aim is to determine the protein structure and regulatory controls present in two classes of cyanobacterial bicarbonate transporters that are required for efficient photosynthesis. This information is now critical to the our goal of redesigning these bicarbonate transporters so they will be functional in plants, thereby contributing to the applied objective of engineering crop plants that could produce good grain yields with reduced water requirements.Read moreRead less
Identification of transcription factor genes involved in the regulation of aspects of photosynthetic capacity in plants. There is increasing evidence to suggest that we may be reaching a yield plateau with many agricultural plants and that future avenues for yield increases may depend on increases in photosynthetic capacity per unit leaf area. Molecular genetic technology offers the promise of the direct manipulation of photosynthetic gene expression to increase photosynthetic capacity. This pro ....Identification of transcription factor genes involved in the regulation of aspects of photosynthetic capacity in plants. There is increasing evidence to suggest that we may be reaching a yield plateau with many agricultural plants and that future avenues for yield increases may depend on increases in photosynthetic capacity per unit leaf area. Molecular genetic technology offers the promise of the direct manipulation of photosynthetic gene expression to increase photosynthetic capacity. This project aims to understand one important part of genetic regulation, the transcription factors, that may determine aspects of photosynthetic capacity. Altered expression of these transcription factors in transgenic plants will be used to test the their ability to control photosynthesis and generate agricultural intellectual property.Read moreRead less
Temperature response and thermal acclimation of mesophyll conductance. Photosynthetic rate and efficiency depend on diffusion of carbon dioxide from the atmosphere into leaf mesophyll cells. Carbon dioxide diffusion is affected by temperature, but we lack knowledge of how this varies between plant species. Stable isotope methodology will be used to characterise the temperature response of this carbon dioxide diffusion step. Plants from contrasting climates will be grown in different temperature ....Temperature response and thermal acclimation of mesophyll conductance. Photosynthetic rate and efficiency depend on diffusion of carbon dioxide from the atmosphere into leaf mesophyll cells. Carbon dioxide diffusion is affected by temperature, but we lack knowledge of how this varies between plant species. Stable isotope methodology will be used to characterise the temperature response of this carbon dioxide diffusion step. Plants from contrasting climates will be grown in different temperature regimes to reveal the extent of variation in adaptation and acclimation to temperature. This will provide new insights towards modifying photosynthesis to increase crop yield and it will also improve forecasting of global atmospheric carbon dioxide fluxes derived from the analysis of atmospheric isotope data.Read moreRead less