Dr. Tonni Grube Andersen is a group leader at the Max Planck Institute for Plant Breeding Research (MPIPZ) since 2019. Dr. Andersen’s research focuses on plant roots and, especially their ability to interact with and shape their surrounding environment in order to optimize plant growth. Dr. Andersen’s group aims to provide insights on how plants communicate with the surroundings to promote a more efficient usage of nutrients and stronger resistance to diseases.

Abstract

“The importance of barriers in a functional relationship”

Casparian strips (CS) need no introduction in this meeting. Due to members of this community, we have gained a tremendous insight into the CS barrier system and how it functions. However, most of this comes from the model Arabidopsis thaliana and we lack deeper insights into the CS in other species – especially the nodule-forming, nitrogen-fixing legumes where the initiation of these specialized bacteria-hosting organs occur in the CS-containing root zone.

With basis on this, we focused on the symbiosis model Lotus japonicus and identified mutants without CS. Combined, our findings reveal a surprising role for the CS in root-shoot communication of N-status which is essential for correct nodule establishment. Moreover, in these mutants, the forming nodules are devoid of vascular-associated CS, which creates an intriguing model to study the role of the CS in controlling metabolic exchange between the plant host and the associated bacteria. Through correlative meta transcript- and metabolomic imaging we were able to study how the homeostasis of nodule-residing bacteriods is affected when to-and-from flow of photo assimilates, nutrients and fixed-N is unrestricted. Taken together, our work establishes a novel toolbox for the study of symbiotic relationships and emphasizes the importance of barriers in spatially restricted plant-microbe associations.