Root Systems Biology: bridging regulatory networks to rhizosphere-scale processes

Our understanding of root biology has advanced over the last decade, in large part due to genetic and genomic approaches in model organisms. Recently, researchers have started to study the mechanisms controlling root growth and development using systems biology approaches. Modeling is set to become much more important as our knowledge of root regulatory pathways becomes increasingly complex and their outputs less intuitive. In order to relate root genotype to phenotype we must move beyond the network scales and employ multiscale modeling approaches to predict emergent properties at the tissue, organ, organism and rhizosphere levels. The interplay between scales is complex and an integrative approach is essential to understand the underlying biological mechanisms. We describe examples where such approaches have been successful and conclude by discussing the merits of developing digital plant models able to span the network to population scales and interact with their environment.