Ph.D., Biochemistry, 1989, The Australian National University, Australia
Research emphasis: Plant functional genomics
Since the turn of the century, genome sequencing of several plant species has revealed the full complement of genes and proteins in these species. Parallel developments in high-throughput analysis of gene transcripts, proteins, and metabolites, and in resources for forward and reverse genetics enable us to determine the roles of genes and proteins in plant biology in a systematic and high-throughput manner. These tools and approaches form part of a new scientific discipline called Functional Genomics, which is transforming the way we do biological research in the 21st century. My group is leading efforts to develop and apply tools for functional genomics in two plant species of interest to agriculture and the emerging bioenergy industry: Medicago truncatula, a model legume closely related to the world's most important forage legume, alfalfa; and Panicum virgatum, or switchgrass, a native C4 grass that is being developed as a biomass crop for biofuel production in the USA. Apart from developing resources for international research on these two species, we are applying the resources to several different areas of legume and switchgrass research.
Our research on Medicago truncatula is quite diverse, although it focuses on aspects of legume biology that are important to agriculture. Several projects focus on genes, genetic regulatory networks, and biochemical processes involved in root nodule development and symbiotic nitrogen fixation (SNF), which is a process of enormous importance to sustainable agriculture. By understanding better the molecular basis of SNF we hope to support future breeding efforts to enhance SNF in pasture and crop legumes. Another project explores the roles of transcription factors (TFs) in controlling seed development, differentiation, and storage metabolism. Legume seeds are an important source of protein, lipid, carbohydrate, secondary metabolites, and minerals for humans and other animals and key TFs may help to optimize the type and amount of these nutrients in legume seeds in the future. A third project area looks at how Medicago and its relative, alfalfa, respond to drought stress with a view to identifying genes that could be used to enhance drought tolerance in alfalfa and other forage or crop legumes. Greater drought tolerance in plants is likely to become more important in future as the share of water allocated to agriculture declines and if rainfall becomes more variable and uneven.
Work on switchgrass began recently and focuses on nutrient recycling during seasonal senescence. Switchgrass is a perennial plant that can be harvested multiple times per year over multiple years. Switchgrass shoots senesce or die-off before winter each year and transfer much of their macro-micronutrients, including N, P, and S to the root system, where they are stored until spring when the nutrients are used to support the growth of new shoots. This recycling of nutrients is important from both ecological and agricultural perspectives, because it helps plants hold on to hard-won nutrients that are limiting in the soil, and can be taken advantage of by judicious timing of harvesting of shoot biomass to minimize the loss of valuable nutrients from the plant-soil system. We are developing various resources for switchgrass functional genomics and using these to identify TFs that regulate senescence. Such TFs may be useful tools to maximize recycling of nutrients between the senescing shoot and the living root, which would minimize the need for fertilizer application to maintain productive fields of switchgrass for biofuel production. Therefore, sustainability of switchgrass production, like that of legumes, is first and foremost in our minds.