Root cap at soil interface: a driving force towards plant adaptation and development
Land plants harbour robust roots to grow in diverse soil ecosystems. The distal end of the primary root tip has specialized tissue, called “root cap.” The evolution of root cap-like structures in early plants rudimentary roots and well-developed root caps in vascular plants hints towards developing an adaptive trait for a localized plant habitat. Root cap interacts with soil and assists roots in penetrating the below ground, avoid/adsorb metals, uptake water, minerals, and regulates rhizosphere microbiota that drives plant-soil feedback. Besides, the root cap governs lateral root patterning and directs root growth in varying conditions. This review article presents the retrospective and our perspective on root cap characters for root-soil interaction. We discussed the anatomy of root cap among the different taxa of land plants and their relevance in diverse habitats and elucidated the root cap functions under various growth conditions. We took advantage of recently published single-cell RNAseq data and shed light on biological relevance of root cap cell-type enriched genes from arabidopsis, rice, maize, and tomato. Additionally, analyzed the transcription factor binding site enrichment in root cap enriched genes and constructed gene-regulatory networks operating in root cap to contribute its multi-faceted role in plant growth and adaptation.