Using Elemental Profiling and Systems Biology to Identify Genes Underlying Toxic Element Uptake in Plants

The vast majority of the elements that make up a seed, with the exception of carbon and oxygen, are obtained from soil via the roots.  These soil-derived elements are required for plant structure, metabolism, protein function, signaling, and proper osmotic and electrostatic potential.  Elemental accumulation requires the integration of processes across biological scales, including interactions with the soil matrix and biota, subcellular localization, metabolism, and gas exchange. Thus, the elemental composition of seeds (the “ionome”), including both beneficial and toxic elements, is a consequence of complex plant-environment interactions with serious nutritional implications.  High-throughput ionomics workflows allow a single inductively coupled plasma mass spectrometer (ICP-MS) to precisely analyze hundreds of samples for more than 20 elements per day. We have used ionomic profiling of 200,000+ maize kernels, soybeans and cotton seeds to detect the genetic and environmental determinants of the ionome.  Using modern genetic approaches, we can easily identify loci that control the ionome in a given environment. We are using several different approaches to integrate ionomic and other systems biology datasets to identify the causal genes underlying these phenotypes. We can use this knowledge to identify genes important for toxic element accumulation in plants.