Root Biology

Research / Root Biology

Border cells are a specialized cell type localized around the root cap of many terrestrial plant species. The exception are those of the Brassicaceae family which possess border-like cells. Border cells are major secretion machines, secreting DNA, mucilage, proteins, and metabolites into the rhizosphere. They have been shown to participate heavily in facilitation of host-microbe interactions. However, they tend to be overlooked in many studies concerning plant roots. As such, their considerable contributions are not properly analyzed. The Sumner lab aims to understand the metabolite basis of border cell host-microbe interactions.

Project One: Construction of a Metabolite Atlas of Spatially Separated Root Tissues in Medicago truncatula

In our efforts to understand the metabolic basis for differentiated root tissue functions, it became necessary to spatially separate these tissues for further study. Our goal was to distinguish metabolites that exhibit localization on a per tissue basis. We distinguished these tissues by Border cells, rhizosphere secretions, root cap, elongation zone, and mature tissue. These samples were analyzed using LCMS and GCMS to probe their metabolite contents. Concurrently with this project, we engaged with another goal to simply the process of displaying large-scale metabolomics data. We accomplished this through development of a metabolite atlas we have named Medicago truncatula Metabolite Atlas. This atlas allows user selection of a metabolite, wherein metabolite localization will be displayed as a heat map overlaying images of the tissues at hand (

Relevant scientific article(s) published by our team:

Project Two: Analysis of Isolated Border Cell Secretions in Response to Commensal and Pathogenic Microbial Elicitation