Abstract

Multicellular organisms are comprised of many cell types with distinct identities and functions. Furthermore, the scale or plasticity of potential responses within cell types also differs dramatically. Our previous work has shown that regulation of developmental plasticity is genetically encoded, and that perturbing ‘plasticity’ genes alters the extent of highly specific root architecture responses to the environment. We are interested in quantifying the level of plasticity in cell types in order to uncover the mechanisms underlying whole organism plasticity.

Formation of nodules as a result of cell division specifically in the legume root cortical cell layer is a developmental mechanism with intriguing parallels to lateral root development from pericycle. It follows that environmental conditions that control formation of these structures should be sensed in a highly cell specific fashion. To detect cell specific changes responses during nodulation and nitrogen influx we use Fluorescence Activated Cell Sorting (FACS) followed by transcriptomics and network inference. This allows us to carry out comparative expression multi-point timecourse profiling between the legume Medicago truncatula and the non-legume Arabidopsis thaliana. It is possible that the genes enabling nodulation already exist in non-legumes, but are not expressed in the appropriate cell types. Reengineering plants to express symbiosis genes under a synthetic set of cell-specific promoters could extend the developmental plasticity of cell types and enable nodulation in non-legume crops.