How the Environment Regulates Root Architecture in Dicots

The efficient acquisition of soil resources (nutrients and water) through the root system is crucial for crop productivity. In order to adapt root growth to the soil environment, plants can optimize their root architecture by initiating primordia and influencing growth of primary roots or lateral roots (LRs). Root architecture results from the integration of genetic programs governing root growth patterns and environmental factors which affect signaling pathways. We review here recent knowledge acquired mainly in Arabidopsis thaliana on primary root and LR development and the impact that different environmental constraints (water, phosphate, nitrate, and sulfate) have on root growth and development. Since Arabidopsis is unable to develop specific organogenesis resulting from symbiotic interactions, we also discuss recent molecular data on the analysis of the nitrogen‐fixing symbiotic nodules and their influence on root architecture in legumes. Finally, molecular analysis of the role of noncoding RNAs in environmentally activated signaling pathways will be discussed. These RNAs are emerging as crucial regulators of differentiation and adaptation to environmental conditions.