Preparation of Photo-Affinity Molecular Probes for the Identification of Gibberellin Receptors. Bioactive gibberellins affect numerous processes during plant growth and development, including seed germination, leaf expansion, stem elongation, flowering and fruit development. However, only very limited information is available regarding their mode of action at the molecular level. The central aim of the project is to prepare a family of photo-affinity molecular probes based on the gibberellin m ....Preparation of Photo-Affinity Molecular Probes for the Identification of Gibberellin Receptors. Bioactive gibberellins affect numerous processes during plant growth and development, including seed germination, leaf expansion, stem elongation, flowering and fruit development. However, only very limited information is available regarding their mode of action at the molecular level. The central aim of the project is to prepare a family of photo-affinity molecular probes based on the gibberellin molecule that will be designed to provide critical information on the location and structure of gibberellin receptors. Screening of the probes for potential effectiveness will be determined initially by the measurement of alpha-amylase produced in a standard barley aleurone assay.Read moreRead less
Comparative Biophysical Studies on Photosystem II of Higher Plants and Cyanobacteria. Photosystem II (PS-II) is one of two light trapping protein assemblies involved in the conversion of light into metabolic energy in all plants and algae. The manganese containing active site of PS-II is responsible for oxygen formation from water. The organisation and functioning of this centre and the detailed mechanism of photochemical energy conversion are not understood. This project will employ a combinati ....Comparative Biophysical Studies on Photosystem II of Higher Plants and Cyanobacteria. Photosystem II (PS-II) is one of two light trapping protein assemblies involved in the conversion of light into metabolic energy in all plants and algae. The manganese containing active site of PS-II is responsible for oxygen formation from water. The organisation and functioning of this centre and the detailed mechanism of photochemical energy conversion are not understood. This project will employ a combination of powerful biophysical techniques to probe the structure and mechanism of PS-II as a knowledge base for eventual genetic manipulation of plants and stategies for artificial photosynthesis.Read moreRead less
Connecting soil nitrogen and plant uptake for greener agriculture. This project will use synthetic organic chemistry, biochemistry, root and rhizosphere biology and rhizosphere modelling to establish detailed mechanistic knowledge of the nitrogen (N) transport and uptake processes at the soil-root interface to develop new, efficient urease and nitrification inhibitors for reliable provision of N to the plant/root system. The reduction of excessive N fertilisation has significant environmental be ....Connecting soil nitrogen and plant uptake for greener agriculture. This project will use synthetic organic chemistry, biochemistry, root and rhizosphere biology and rhizosphere modelling to establish detailed mechanistic knowledge of the nitrogen (N) transport and uptake processes at the soil-root interface to develop new, efficient urease and nitrification inhibitors for reliable provision of N to the plant/root system. The reduction of excessive N fertilisation has significant environmental benefits by reducing greenhouse gas emissions and water pollution. This project will lead to a breakthrough for the triple challenge of food security, environmental degradation and climate change, while improving plant productivity and increasing the profitability of agriculture through lower fertiliser costs.Read moreRead less
Disorder as a novel determinant of photosynthetic structure and function: an experimental study. Australia enjoys a world reputation in photosynthesis research, typified by hosting the 2001 International Photosynthesis Congress. It also has a claim to fame for theoretical work in non-equilibrium thermodynamics concerning production of disorder or entropy, yielding new insights into planetary climates. This experimental project investigates the novel relation between entropy/entropy production ....Disorder as a novel determinant of photosynthetic structure and function: an experimental study. Australia enjoys a world reputation in photosynthesis research, typified by hosting the 2001 International Photosynthesis Congress. It also has a claim to fame for theoretical work in non-equilibrium thermodynamics concerning production of disorder or entropy, yielding new insights into planetary climates. This experimental project investigates the novel relation between entropy/entropy production and the structure/function of the solar powerhouse of plants (chloroplasts), and addresses fundamental questions at the interface of biology and physics. The research explores chloroplasts as a manifestation of the all-pervading Second Law of Thermodynamics, advancing Australia's contribution to basic science and helping to train researchers.Read moreRead less
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
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
Molecular analysis of photosynthetically-linked, active CO2 uptake and CO2 signal transduction by cyanobacteria (blue-green algae). Cyanobacteria (blue-green algae) have evolved a very efficient means of capturing and concentrating CO2 for photosynthetic fixation into sugars, the basic building blocks for cell growth. This process is dependent on the operation of several unique, active uptake systems for CO2 and HCO3-, with their genetic expression regulated by CO2 supply. This proposal will cap ....Molecular analysis of photosynthetically-linked, active CO2 uptake and CO2 signal transduction by cyanobacteria (blue-green algae). Cyanobacteria (blue-green algae) have evolved a very efficient means of capturing and concentrating CO2 for photosynthetic fixation into sugars, the basic building blocks for cell growth. This process is dependent on the operation of several unique, active uptake systems for CO2 and HCO3-, with their genetic expression regulated by CO2 supply. This proposal will capitalize on our progress in describing the functional genetics of this process and aims to elucidate the mechanism of active CO2 uptake and the way that cells sense the ambient CO2 concentration. The information gained is likely to be useful for designing improved crops.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
Clocks in crops: exploring the role of circadian rhythms in crop adaptation. The project aims to analyse how the circadian clock provides adaptive advantages in legumes and cereals, two major crop groups of global importance. The project expects to produce new fundamental knowledge about how the clock in these crops coordinates their development, physiology, and metabolism in response to environmental cues. The anticipated outcome is a better understanding of key similarities and differences in ....Clocks in crops: exploring the role of circadian rhythms in crop adaptation. The project aims to analyse how the circadian clock provides adaptive advantages in legumes and cereals, two major crop groups of global importance. The project expects to produce new fundamental knowledge about how the clock in these crops coordinates their development, physiology, and metabolism in response to environmental cues. The anticipated outcome is a better understanding of key similarities and differences in clock functions in different species. Another is knowledge of how the ancient clock gene variants still in use today may limit the current or future performance of those crops. This will provide significant benefits, such as to improve productivity of crop plants in diverse and changing environments.Read moreRead less
New approaches to unravelling post-translational controls operating on the cyanobacterial carbon dioxide concentrating mechanism. Marine blue-green algae contribute to global primary productivity but their carbon dioxide acquisition processes are poorly understood. The project will employ mutagenesis and genome sequencing to discover the controls that regulate carbon dioxide uptake processes required for efficient photosynthesis and use this data to aid in engineering crop plants that use less w ....New approaches to unravelling post-translational controls operating on the cyanobacterial carbon dioxide concentrating mechanism. Marine blue-green algae contribute to global primary productivity but their carbon dioxide acquisition processes are poorly understood. The project will employ mutagenesis and genome sequencing to discover the controls that regulate carbon dioxide uptake processes required for efficient photosynthesis and use this data to aid in engineering crop plants that use less water.Read moreRead less