Functions of rhizosheath on facilitating the uptake of water and nutrients under drought stress: A review

Background and Aims: The optimal management of plant nutrition is an effective strategy for sustainable agriculture under various conditions. Soil drying is one of the main limiting factors for plant nutrient acquisition. Plants imposed to these limitations have evolved several strategies such as modifying root-to-shoot ratio, modifying their root anatomy, modifying microbial diversity, and engineering their surrounding soil via rhizodeposition and rhizosheath formation. Rhizosheath is referred to as the soil that remained attached to the root system after being removed from the soil and shacked. Here we reviewed the processes contributing to rhizosheath formation and the mechanisms underlying how it affected the plant's ability to uptake water and nutrients. Methods: To shed light on the unexplored aspects of rhizosheath and identify potential research directions, we conducted a comprehensive review of the relevant literature on the mechanisms of rhizosheath formation and its impacts on water and nutrient uptake. Results: The results showed that the presence of mucilage, root hairs and dry-rewetting cycles play a vital role in the formation and strength of rhizosheath. Rhizosheath enables plants to adapt to their environment by keeping the soil and roots hydraulically connected during a soil drying cycle and promoting water and nutrients uptake at the roots-soil interface. Conclusion: It is concluded that the rhizosheath is the most chemically and biologically active part of the soil. Breeding plants to strengthen their ability to form stable rhizosheath may be one solution to achieving a sustainable agricultural system and maintaining agricultural production under drought stress.