Date: 13th September 2023
Timing of root barriers control soil-to-shoot integration of rhizosphere status
Location: Seminar room 228, Laboratory Building, Koetilantie 5 and remotely via Zoom
Host: Ari-Pekka Mähönen
Abstract: In roots, formation of the Casparian strip in the endodermal cell walls provides a mechanism for selective uptake of nutrients and water. Establishment of this filter is under spatial surveillance by a receptor-ligand mechanism termed the Schengen pathway. This system provides a mechanism to initiate downstream signaling responses in case of dysfunctional barrier establishment. Due to this interconnected nature, the endogenous physiological role of this survaillance mechanism remain difficult to untangle from the direct barrier function. This is in particularly evident in complex growth setups where multiple inputs are integrated into general whole-plant responses. we addressed this by rewiring the genetic network that underlies root barrier formation. We created plants with enhanced, Schengen-independent Casparian strip formation that are not only suitable to probe the role of stronger barrier establishment, but also to evaluate the associated signaling output independently. With focus on the latter, we subjected the rewired plants, as well as a number of established barrier mutants, to multifaceted growth conditions including nitrogen fertilized agricultural soil conditions. By profiling their above- and belowground (a)biotic responses our work reveals that, while increased Casparian strip formation mainly provides the plant with an improved stress resistance, the Schengen pathway is necessary for establishment of a growth-promoting root microbiome and serves to convey information of soil nitrogen status to the shoot. This identifies the Schengen pathway as an essential receptor-based signaling hub for adaptive integration of barrier status, nutritional responses and (a)biotic signaling between above- and belowground tissues.
Tonni is a group leader in plant molecular physiology and root development at the Max Planck Institute for Plant Breeding Research and a Sofja Kovalevskaya Fellow of the Alexander von Humboldt Society. He received his Ph.D. from the University of Copenhagen in 2012, working under Prof Barbara Ann Halkier. After a short period in the lab of Prof. Meike Burow, he joined the lab of Prof. Niko Geldner, University of Lausanne, Switzerland in 2014 as a Marie Curie research fellow. In 2019 he became an independent research group leader at the Max Planck Institute for Plant Breeding in Cologne, Germany. Dr. Andersen research is focused on understanding how plants communicate with the surroundings with the aim to provide a more efficient usage of nutrients and a stronger resistance to diseases. To address this, his lab employs a mixture of high-end fluorescence-based microscopical techniques, near-native physiological setups, microfluidics, transcript- and translatomics as well as microbiome-based community studies.