Over the last 100 years, the atmospheric concentration of carbon dioxide has dramatically increased, in major part due to the burning of fossil fuels, recent rapid industrialization, and land use changes. The predicted effects of continued climate change are complex but include effects on air and surface temperature, with coincident effects on water availability. Soil temperature can influence root growth, cell elongation, root length and extension, initiation of new lateral roots and root hairs, and root branching. These effects are likely manifestations of the variety of physiological effects brought about by temperature on plant roots; including changes in root respiration, nutrient uptake, as well as physicochemical effects on the soil environment (e.g., changes in nitrogen mineralization). Ambient temperature changes also affects other parts of the plant (e.g., photosynthetic rates), which also affects below ground growth and physiology. When we include in this discussion issues of plant genetic variation, as well as the effects of temperature on water availability, the full complexity of the effects of climate change on the plant root environment becomes clear.
In order to properly understand the effects of climate change, models must be developed that predict impacts across broad temporal (seconds to millennia) and spatial (microns to global) scales. In order to be useful, these models must draw upon accurate experimental data. Systems biology seeks to address these needs by providing a comprehensive, quantitative analysis of the manner in which all the components of a biological system interact functionally over time and space. The recent explosion of interest in systems biology is the result of the development of new tools for system-level analysis of cellular function and the availability of an increasing number of full genome sequences, which enables the full application of these new technologies. The ultimate goal is a new, predictive view of biological function, supplanting the older descriptive understanding. Hence, there is a need to integrate system approaches to understand the effects of climate change on molecules, cells, organisms and ecosystems.
However, the promise of this new ‘predictive’ science has yet to achieve its full potential. A number of challenges remain. For example, although the new tools do indeed provide for a full systems view of cellular function, integration of dissimilar data (e.g., proteomics, metabolomics, transcriptomics, etc.) remains a formidable challenge. Among the issues compounding the problems of data integration is the issue of “signal dilution”, which results from the fact that most studies average the response of whole tissues, obscuring the actual cellular response. Hence, it is impossible to discern the difference, for example, of a gene that is expressed at a low level in all cells from a gene that is expressed at a very high level, but only in a few cells. Approaches are needed to conduct functional genomics on single cells.
Our work addresses the question of signal dilution by focusing, specifically, on soybean root hair cells, which represent a single, differentiated cell type. Over the past 5 years, we have established the soybean root hair cell as an excellent platform for plant systems biology studies. It is now arguably the best characterized cell type in plant biology, as exemplified by our various publications, databases and additional information yet to be published (see other pages on this site).
Our vision is to utilize the soybean root hair system to explore, at a systems level, the biology of a single, differentiated plant cell type, while gaining novel insight into the impacts of temperature and water availability on a crucial root cell necessary for nutrient uptake. The research should provide unambiguous measurements of the impact of these environmental factors on plant cell function, without the compounding effects of tissue dilution. The proposed research will focus on defining the transcriptional, metabolomic and proteomic response of the soybean root hair cell to variations in temperature and water availability. These data will allow the development of computational models to examine regulatory networks that function at a single cell level to control the response to environmental change. The data obtained should provide a better understanding of the impacts of climate change (heat and water limitation) on plant root physiology.