One of our main topics of interest is the study of endodermis as an invariant feature of vascular plants. It fulfils a crucial barrier function separating the extracellular space of outer cell layers from the inner apoplastic space of the vascular bundles. The "Casparian strip" has been defined as an area where endodermal cells secrete hydrophobic material in a highly localised and coordinated fashion to act as a barrier. The Casparian strip is composed of a ligno-suberic polymer, which forms an extensive, supra-cellular network. We demonstrate that there is no lateral diffusion across the Casparian Strip Domain (CSD) between outer and inner plasma membrane domains and we have identified transporters that localise to one or the other membrane region, depending on their function in uptake or efflux of nutrients. In addition we identified a new class of proteins that mark and predict the formation of the CSD. We will investigate the mechanisms underlying the formation of the Casparian Strip sub-domain on cellular surface and the localisation of proteins to either its central or peripheral side.

• A two-way molecular dialogue between embryo and endosperm is required for seed development
  Doll, N. M.; Royek, S.; Fujita, S.; Okuda, S.; Chamot, S.; Stintzi, A; Widiez, T; Hothorn, M; Schaller, A; Geldner, N; Ingram, G
  Science  367(6476): 431-+ SI DOI: 10.1126/science.aaz4131 JAN 24 2020
• Co-incidence of Damage and Microbial Patterns Controls Localized Immune Responses in Roots
  Zhou, Feng; Emonet, Aurelia; Tendon, Valerie Denervaud; Marhavy, Peter; Wu, Dousheng; Lahaye, Thomas; Geldner, Niko
  Cell  180(3): 440-+ DOI: 10.1016/j.cell.2020.01.013 FEB 6 2020
• Molecular mechanism for the recognition of sequence-divergent CIF peptides by the plant receptor kinases GSO1/SGN3 and GSO2
  Okuda, Satohiro; Fujita, Satoshi; Moretti, Andrea; Hohmann, Ulrich; Doblas, Veronica G.; Ma, Y; Pfister, A; Brandt, B; Geldner, N; Hothorn, M
  Proceedings Of The National Academy Of Sciences Of The United States Of America, 10.1073/pnas.1911553117, FEB 4 2020
• Root endodermal barrier system contributes to defence against plant-parasitic cyst and root-knot nematodes
  Holbein, J; Franke, RB; Marhavy, P; Fujita, S; Gorecka, M; Sobczak, M; Geldner, N; Schreiber, L; Grundler, FMW; Siddique, S
  PLANT JOURNAL, 10.1111/tpj.14459 
• Single-cell damage elicits regional, nematode-restricting ethylene responses in roots
  Marhavy, P; Kurenda, A; Siddique, S; Tendon, VD; Zhou, F; Holbein, J; Hasan, MS; Grundler, FMW; Farmer, EE; Geldner, N
  EMBO JOURNAL, 38 (10):10.15252/embj.2018100972 MAY 15 2019
• The Casparian strip-one ring to bring cell biology to lignification?
  Barbosa, ICR; Rojas-Murcia, N; Geldner, N
  CURRENT OPINION IN BIOTECHNOLOGY, 56 121-129; 10.1016/j.copbio.2018.10.004 APR 2019
• Diffusible repression of cytokinin signalling produces endodermal symmetry and passage cells.
  Andersen TG, Naseer S, Ursache R, Wybouw B, Smet W, De Rybel B, Vermeer JEM, Geldner N.
  Nature. 2018 Mar 22;555(7697):529-533. doi: 10.1038/nature25976. Epub 2018 Mar 14. PMID:29539635
• A protocol for combining fluorescent proteins with histological stains for diverse cell wall components.
  Ursache R, Andersen TG, Marhavý P, Geldner N.
  Plant J. 2018 Jan;93(2):399-412. doi: 10.1111/tpj.13784. PMID:29171896
• Surveillance of cell wall diffusion barrier integrity modulates water and solute transport in plants
  Wang, P; Calvo-Polanco, M; Reyt, G; Barberon, M; Champeyroux, C; Santoni, V; Maurel, C; Franke, RB; Ljung, K; Novak, O; Geldner, N; Boursiac, Y; Salt, DE
  SCIENTIFIC REPORTS, 9 10.1038/s41598-019-40588-5 MAR 12 2019
• Root zone-specific localization of AMTs determines ammonium transport pathways and nitrogen allocation to shoots
  Duan, FY; Giehl, RFH; Geldner, N; Salta, DE; von Wiren, N
  PLOS BIOLOGY, 16 (10):10.1371/journal.pbio.2006024 OCT 2018
• Minimum requirements for changing and maintaining endodermis cell identity in the Arabidopsis root
  Drapek, C; Sparks, EE; Marhavy, P; Taylor, I; Andersen, TG; Hennacy, JH; Geldner, N; Benfey, PN
  NATURE PLANTS, 4 (8):586-595; 10.1038/s41477-018-0213-y AUG 2018
• Correction: Diffusible repression of cytokinin signalling produces endodermal symmetry and passage cells
  Andersen, Tonni Grube; Naseer, Sadaf; Ursache, Robertas;  Wybouw, Brecht; Smet, Wouter; De Rybel, Bert; Vermeer, Joop EM; Geldner, Niko
  NATURE (2018) DOI: 10.1038/nature25976), NATURE 10.1038/s41586-018-0231-y

• The root endodermis as a polar epithelium 
• Receptor trafficking in plants 
• Waves lines: Mapping the complexity of the plant membrane system

• WAVE lines: a set of fluorescent markers for plant membrane compartments
• The pNIGEL recombination vector series
• Live cell imaging
• Forward and reverse genetic screens
• Proteomic approaches