Fröschel Lab (now at Bot II, University of Würzburg)

The endodermis is a cell-layer of the root that separates the inner vasculature from the outer cortex. Although it is a thin cell-layer, it is of central importance. Hydrophobic cell wall reinforcements, such as the Casparian strip (CS) or suberin deposits, seal the endodermal extracellular space and block free diffusion. This allows a selective uptake of water and nutrients across the plasma membrane and controls the bidirectional flow to the vasculature. To date, little is known about how the structures surrounding the endodermal cells protect the root from microbial invasion. It is essential for the plant to keep microbes from the xylem vessels, where they can otherwise easily spread systemically with the water flow. Using the highly specialized and morphologically well-defined endodermis, we address the question of how barrier assembly is regulated and adapted to different stress situations. We decipher multicomponent networks that control endodermis-specific gene expression and distinguish between transcriptional (e.g., characterization of cell type-specific transcription factors) and post-transcriptional (e.g., cell type-specific translational adaptation) control mechanisms. Knowing more about how endodermal features arise will provide new opportunities for breeding more resilient crop plants.

Literature: Fröschel et al., Cell Host and Microbe 2021

Researcher: Christian Fröschel

The rhizosphere harbors a highly complex microbial community that is in close contact with plant roots. Yet, just a few mechanisms are known by which roots defend against microorganisms. New knowledge of root-microbe interactions is required to develop novel strategies in agriculture and reduce crop losses. We use fungi of the genus Verticillium as model organisms to study interactions of the root with soil-borne microbes. These fungi are characterized by an unusual colonization strategy: after the hyphae have reached the host roots, they traverse all concentric cell layers and penetrate the central cylinder. Once there, the fungus spreads to the above-ground plant parts via the water vessels. The infected host plant suffers growth defects and develops premature senescence, chlorosis or wilting. We have established several infection systems and use Arabidopsis, oilseed rape as well as tomato as model plants to study how the fungi spread in their host plants from the roots to the shoot. We are investigating how the plant defends itself against the fungus and how the fungus can manipulate the plant's immune system utilizing effectors.

Literature: Fröschel, Plant Methods 2021

Researchers: Christian Fröschel, Alexander Marsell