Our paper on "Natural Genetic Variation in Selected Populations of Arabidopsis thaliana Is Associated with Ionomic Differences" has just been published in PLoS ONE. I'm really happy that this paper is out because it demonstrates something that we have been talking about for several years now: that the ionome is dynamic and interconnected, and the relationships between elements are dependent on both genetics and the environment. The first three figures in this paper describe experiments which were the basis for three other papers that we have already published. Here is the abstract and none technical summary:
Controlling elemental composition is critical for plant growth and development as well as the nutrition of humans who utilize plants for food. Uncovering the genetic architecture underlying mineral ion homeostasis in plants is a critical first step towards understanding the biochemical networks that regulate a plant's elemental composition (ionome). Natural accessions of Arabidopsis thaliana provide a rich source of genetic diversity that leads to phenotypic differences. We analyzed the concentrations of 17 different elements in 12 A. thaliana accessions and three recombinant inbred line (RIL) populations grown in several different environments using high-throughput inductively coupled plasma- mass spectroscopy (ICP-MS). Significant differences were detected between the accessions for most elements and we identified over a hundred QTLs for elemental accumulation in the RIL populations. Altering the environment the plants were grown in had a strong effect on the correlations between different elements and the QTLs controlling elemental accumulation. All ionomic data presented is publicly available at www.ionomicshub.org.
Understanding how plants regulate element composition of tissues is critical for agriculture, the environment, and human health. Sustainably meeting the increasing food and biofuel demands of the planet will require growing crops with fewer inputs such as the primary macronutrients phosphorus (P) and potassium (K). Ionomics is the study of elemental accumulation in living systems using high-throughput elemental profiling. With this technique, we can rapidly generate large quantities of data on thousands of samples, allowing for the profiling of large genetic mapping populations and the discovery of hundreds of loci important for elemental accumulation. We have used this approach to sample the natural diversity present in collections of a model plant, the wild mustard Arabidopsis, and mapping populations derived from those collections. We find that when the soil environment changes, the identity of the genes important for elemental accumulation changes as well. We also find that elements will have different relationships between them depending on the environment and the lines under study. This suggests that crop varieties developed for improved elemental uptake and accumulation will be highly environment specific.