Evolution of diverse symbiotic phenotypes among native soil bacteria following spread of a genomic island from a rhizobial inoculant. The quality of legume protein depends on symbiotic nitrogen fixation by root nodule bacteria (RNB). Sustainable legume production in Australian agriculture depends on legume inoculation with effective strains of these bacteria. Unfortunately inoculant strains transfer DNA to other soil bacteria resulting in soil populations of RNB that compete for nodulation but a ....Evolution of diverse symbiotic phenotypes among native soil bacteria following spread of a genomic island from a rhizobial inoculant. The quality of legume protein depends on symbiotic nitrogen fixation by root nodule bacteria (RNB). Sustainable legume production in Australian agriculture depends on legume inoculation with effective strains of these bacteria. Unfortunately inoculant strains transfer DNA to other soil bacteria resulting in soil populations of RNB that compete for nodulation but are less effective in nitrogen fixation. This transfer of DNA threatens a $2 billion asset in Australian agriculture. We will use molecular microbial ecology to investigate the mechanisms of genetic transfer of symbiotic DNA in RNB, and use this knowledge to prevent it.Read moreRead less
Molecular dissection of resistance to subterranean clover mottle virus using Medicago truncatula. Plant virus diseases cause economic losses in most crop plants. Grain and pasture legumes are an important component of Australian agricultural cropping sytems, and provide human food and animal feed: they also contribute to higher yields of crops like cereals when grown in rotation, by providing nitrogen and a disease break. In this project, the 'model' legume, Medicago truncatula ('Barrel Medic') ....Molecular dissection of resistance to subterranean clover mottle virus using Medicago truncatula. Plant virus diseases cause economic losses in most crop plants. Grain and pasture legumes are an important component of Australian agricultural cropping sytems, and provide human food and animal feed: they also contribute to higher yields of crops like cereals when grown in rotation, by providing nitrogen and a disease break. In this project, the 'model' legume, Medicago truncatula ('Barrel Medic') will be used to identify a new virus resistance gene. The knowledge gained will be used to improve resistance to viruses in crop legumes, so reducing losses and aiding sustainability of production. This will support rural communities and the national economy.Read moreRead less
Does plant phosphorus economy determine ecological status in biodiverse Australian communities? The phosphorus (P)-impoverished nature of the soils of south-western Australia has allowed the evolution of many plant species that are amazingly efficient at acquiring and utilising P. Among the most P efficient are species of the Proteaceae, which produce cluster roots. We will explore why less efficient species can co-occur with the very efficient Proteaceae. A deep and thorough understanding of th ....Does plant phosphorus economy determine ecological status in biodiverse Australian communities? The phosphorus (P)-impoverished nature of the soils of south-western Australia has allowed the evolution of many plant species that are amazingly efficient at acquiring and utilising P. Among the most P efficient are species of the Proteaceae, which produce cluster roots. We will explore why less efficient species can co-occur with the very efficient Proteaceae. A deep and thorough understanding of the mechanism determining P efficiency of these species will contribute significantly to our basic understanding of P nutrition in plants and to our understanding of the P-impoverished ecosystems of the southwest. It will also assist in developing crops that are more efficient at acquiring and/or utilising P.Read moreRead less
Carboxylate exudation and phosphate nutrition in Hakea prostrata (Proteaecea). Nonmycorrhizal Proteaceae are very successful in acquiring phosphate from nutrient-impoverished soils; their cluster roots account for this. They are also extremely sensitive to phosphate toxicity. We will elucidate aspects of production and release of carboxylates that are associated with functioning of cluster roots, using Hakea prostrata (Proteaceae) as a model. Types and rates of exudation by cluster roots, as in ....Carboxylate exudation and phosphate nutrition in Hakea prostrata (Proteaecea). Nonmycorrhizal Proteaceae are very successful in acquiring phosphate from nutrient-impoverished soils; their cluster roots account for this. They are also extremely sensitive to phosphate toxicity. We will elucidate aspects of production and release of carboxylates that are associated with functioning of cluster roots, using Hakea prostrata (Proteaceae) as a model. Types and rates of exudation by cluster roots, as influenced by development and environmental signals, will be assessed. Our findings will provide key information on adaptive mechanisms associated with both phosphate acquisition from phosphate-fixing soils and phosphate toxicity.Read moreRead less
Expression profiling of giant cells induced in host plant roots by root-knot nematodes. Root-knot nematodes cause crop losses of over $400 million per annum in Australia. Control by toxic chemical nematicodes is expensive and can pollute groundwater. Benefits from this research for the Australian community are: (i) it will ensure that Australian researchers stay at the forefront of research in plant nematology, (ii) it provides significant local and international linkages that will stimulate res ....Expression profiling of giant cells induced in host plant roots by root-knot nematodes. Root-knot nematodes cause crop losses of over $400 million per annum in Australia. Control by toxic chemical nematicodes is expensive and can pollute groundwater. Benefits from this research for the Australian community are: (i) it will ensure that Australian researchers stay at the forefront of research in plant nematology, (ii) it provides significant local and international linkages that will stimulate research outputs, and (iii) new knowledge will be generated on how plants respond to attack by nematodes - this will generate new intellectual property, leading to better control methods and reduced costs that will support rural communities, and reduce environmental pollution.Read moreRead less
Using modelling to optimise the structure and function of crop root systems for dryland agriculture. The crop root systems are poorly suited to harsh conditions in Australian agriculture, especially as climate is getting drier. Poor water-use efficiency lowers crop yields below the potential yield; moreover, unutilised water and nutrients contribute to environmental problems, eg salinity and eutrophication. This project will use our simulation model to develop computer-aided design of 3-D root s ....Using modelling to optimise the structure and function of crop root systems for dryland agriculture. The crop root systems are poorly suited to harsh conditions in Australian agriculture, especially as climate is getting drier. Poor water-use efficiency lowers crop yields below the potential yield; moreover, unutilised water and nutrients contribute to environmental problems, eg salinity and eutrophication. This project will use our simulation model to develop computer-aided design of 3-D root structure and function (water and nutrient uptake) tailored to particular environments. Modelling will also link suitable root traits to genetic markers in well-characterised lupin germplasm. The blueprint developed here will be adaptable to other crops. The project will enhance breeding for increased water- and nutrient-use efficiency.Read moreRead less
Role of intracellular calcium homeostasis and aluminium transport across the plasma membrane in aluminium toxicity to plants. Aluminium is the most important yield-limiting factor in acid soils throughout the world. The problem of aluminium toxicity is aggravated by continuous acidification of arable land. Mechanisms of aluminium toxicity in plant cells are poorly understood. The present project seeks to elucidate the molecular basis of the interaction between intracellular calcium homeostasis, ....Role of intracellular calcium homeostasis and aluminium transport across the plasma membrane in aluminium toxicity to plants. Aluminium is the most important yield-limiting factor in acid soils throughout the world. The problem of aluminium toxicity is aggravated by continuous acidification of arable land. Mechanisms of aluminium toxicity in plant cells are poorly understood. The present project seeks to elucidate the molecular basis of the interaction between intracellular calcium homeostasis, cytosolic pH and aluminium uptake across the plasma membrane in aluminium toxicity to plants. Knowledge of primary triggers of aluminium toxicity will pay off in a breeding programme aimed at selecting crop genotypes with increased resistance to aluminium toxicity.Read moreRead less
Aluminium uptake across the root-cell plasma membrane. Aluminium toxicity limits crop growth in acid soils that occupy about 24 million hectares of agricultural land in Australia. Liming can increase pH of the surface soil, but is frequently too expensive in the low-input Australian agriculture. Surface-applied lime is poorly effective in ameliorating subsoil acidity, and incorporating lime deep into the profile is prohibitively expensive and technically difficult. Hence, Al-resistant crop culti ....Aluminium uptake across the root-cell plasma membrane. Aluminium toxicity limits crop growth in acid soils that occupy about 24 million hectares of agricultural land in Australia. Liming can increase pH of the surface soil, but is frequently too expensive in the low-input Australian agriculture. Surface-applied lime is poorly effective in ameliorating subsoil acidity, and incorporating lime deep into the profile is prohibitively expensive and technically difficult. Hence, Al-resistant crop cultivars are important part of sustainable farming in Australia. This project will characterise early triggers of Al toxicity in plants, providing a foundation for increasing Al resistance in crop cultivars. Understanding the physiological basis of Al toxicity will lead to improved crop breeding strategies.Read moreRead less
Genome Approaches to Investigate Metabolic Coordination in Plant Cells. Metabolism of C and N in legume nodules requires interaction between the symbiotic bacteria and plant organelles, particularly metabolism in plastids and mitochondria. Fixed N is assimilated through the de novo synthesis of purines in both plastids and mitochondria. However, each of the nine pathway enzymes is encoded by a single gene, indicating each protein is targeted to both organelles. Purine metabolism will provide ....Genome Approaches to Investigate Metabolic Coordination in Plant Cells. Metabolism of C and N in legume nodules requires interaction between the symbiotic bacteria and plant organelles, particularly metabolism in plastids and mitochondria. Fixed N is assimilated through the de novo synthesis of purines in both plastids and mitochondria. However, each of the nine pathway enzymes is encoded by a single gene, indicating each protein is targeted to both organelles. Purine metabolism will provide a model to assess the more general occurrence of dual-targeted proteins in plants. The aim is to identify and eventually exploit the signalling mechanism(s) that mediate communication between plastids and mitochondria.Read moreRead less
Protein Complexes and Supercomplexes of Plant Organelles. Ample parts of plant primary metabolism occur in subcellular structures called mitochondria, plastids and peroxisomes. They are vital for plant growth and development and are central to the early success of germinating and growing seedlings. This project intends to analyze the protein complexes and supercomplexes within these organelles using state of the art instrumentation and technologies. Findings from this research have the potential ....Protein Complexes and Supercomplexes of Plant Organelles. Ample parts of plant primary metabolism occur in subcellular structures called mitochondria, plastids and peroxisomes. They are vital for plant growth and development and are central to the early success of germinating and growing seedlings. This project intends to analyze the protein complexes and supercomplexes within these organelles using state of the art instrumentation and technologies. Findings from this research have the potential to directly flow into the plant biotechnology industry and could assist the future development of Australian agriculture through genetic improvements. The expertise developed by this work will ensure that Australia is well placed to meet future needs and to generally improve agricultural technology. Read moreRead less