Root responses to abiotic stress: a comparative look at root system architecture in maize and sorghum

Under all environments, roots are important for plant anchorage and acquiring water and nutrients. However, there is a knowledge gap regarding how root architecture contributes to stress tolerance in a changing climate. Two closely related plant species, maize and sorghum, have distinct root system architectures and different levels of stress tolerance, making comparative analysis between these two species an ideal approach to resolve this knowledge gap. However, current research has focused on shared aspects of the root system that are advantageous under abiotic stress conditions rather than on differences. Here we summarize the current state of knowledge comparing the root system architecture relative to plant performance under water deficit, salt stress, and low phosphorus in maize and sorghum. Under water deficit, steeper root angles and deeper root systems are proposed to be advantageous for both species. In saline soils, a reduction in root length and root number has been described as advantageous, but this work is limited. Under low phosphorus, root systems that are shallow and wider are beneficial for topsoil foraging. Future work investigating the differences between these species will be critical for understanding the role of root system architecture in optimizing plant production for a changing global climate. Plant root systems are important for crop productivity. Here we highlight the shared and distinct responses of root systems to environmental stress conditions in maize and sorghum.

Automated summary

Root systems play a crucial role in plant performance and adaptation to various environments. Comparative analysis of root system architecture between maize and sorghum, two related plant species with different stress tolerance levels, can help bridge the knowledge gap regarding the contribution of root architecture to stress tolerance in a changing climate. Steeper root angles and deeper root systems are proposed to be advantageous under water deficit conditions for both species. Limited research suggests that a reduction in root length and number may be beneficial in saline soils. Under low phosphorus conditions, shallow and wider root systems are beneficial for topsoil foraging. Future research focusing on the differences between these species is critical for understanding the role of root system architecture in optimizing plant production in a changing global climate.