Functional interactomics of auxin transport

Molecular Plant Physiology - Hormone Transport

Work in our group is concentrating on the individual roles of auxin catalysts – members of ABCB/PGP- and PIN families - in auxin transport, their functional interaction and regulation and their impact on auxin-mediated plant physiology and plant development. Although ABCB- and PIN-mediated auxin efflux can apparently function independently, ABCBs and PINs are able to interactively and coordinately transport auxin. The current model is that in interacting cells, multilaterally expressed ABCBs minimize apoplastic reflux while polar ABCB-PIN interactions provide the basis for specific, vectorial auxin streams.

Meanwhile, we have substantially characterized the FKBP42, TWISTED DWARF1 (TWD1), as a positive regulator of ABCB-catalyzed auxin transport by protein-protein interaction (Fig. 1). ABCB-TWD1 interaction and thus auxin flows are disrupted by binding of the diagnostic auxin efflux inhibitor, NPA, suggesting that ABCBs and TWD1 are key components of the NPA-sensitive auxin efflux complex. Recent work has identified flavonols as endogenous modulators of auxin transport by inhibiting ABCBs and promoting asymmetric PIN shifts in the root (Fig. 2). Moreover, by means of chemical genomics, we have identified a novel ABCB-specific auxin transport inhibitor, called BUM.


Recent Publications

  • ABCG36/PEN3/PDR8 Is an Exporter of the Auxin Precursor, Indole-3-Butyric Acid, and Involved in Auxin-Controlled Development
    Aryal, B; Huynh, J; Schneuwly, J; Siffert, A; Liu, J; Alejandro, S; Ludwig-Muller, J; Martinoia, E; Geisler, M
    FRONTIERS IN PLANT SCIENCE, 10 10.3389/fpls.2019.00899 JUL 9 2019
  • HSP90 and co-chaperones: a multitaskers' view on plant hormone biology
    di Donato, M; Geisler, M
    FEBS LETTERS, 593 (13):1415-1430; SI 10.1002/1873-3468.13499 JUL 2019
  • A substrate of the ABC transporter PEN3 stimulates bacterial flagellin (flg22)-induced callose deposition in Arabidopsis thaliana
    Matern, A; Bottcher, C; Eschen-Lippold, L; Westermann, B; Smolka, U; Doll, S; Trempel, F; Aryal, B; Scheel, D; Geisler, M; Rosahl, S
    JOURNAL OF BIOLOGICAL CHEMISTRY, 294 (17):6857-6870; 10.1074/jbc.RA119.007676 APR 26 2019
  • The auxin influx carrier, OsAUX3, regulates rice roots development and response to Al stress.
    Wang M, Qiao Y, Yu C, Chen H, Sun, C, Huang L, Li, C, Geisler M,Qian Q, Jiang DA
    Plant Cell & Environ. 1-14, doi: 10.1111/pce.13478   2019
  • Tomato ATP-Binding Cassette Transporter SlABCB4 Is Involved in Auxin Transport in the Developing Fruit
    Ofori PA; Geisler M; di Donato M; Pengchao H; Otagaki S; Matsumoto S; Shiratake K
    PLANTS-BASEL, 7 (3):10.3390/plants7030065 2018
  • Seeing is better than believing: visualization of membrane transport in plants
    Geisler, M
    CURRENT OPINION IN PLANT BIOLOGY 46, Pages: 104-112, DOI: 10.1016/j.pbi.2018.09.005, DEC 2018
  • A transportome-scale amiRNA-based screen identifies redundant roles of Arabidopsis ABCB6 and ABCB20 in auxin transport
    Zhang, YQ; Nasser, V; Pisanty, O; Omary, M; Wulff, N; Di Donato, M; Tal, I; Hauser, F; Hao, PC; Roth, O; Fromm, H; Schroeder, JI; Geisler, M; Nour-Eldin, HH; Shani, E
    NATURE COMMUNICATIONS, 9 10.1038/s41467-018-06410-y OCT 11 2018
Geisler Markus

PD Dr. Markus Geisler
University of Fribourg
Department of Biology
1700 Fribourg

Tel: +41 (0)26 300 88 27

Research topics

  • Interactomics and cell biology of auxin transport complexes
  • Drug-modulation of transport complexes
  • Regulation of auxin catalystis by protein phosphorylation
  • Chemical genetic screens for natural and synthetic growth regulators
  • In silico analysis of transport complex functionality and interaction
  • Auxin transporter-cytoskeleton interaction



  • Hormone transport and action
  • Arabidopsis developmental biology
  • Transporter structure-function relationships
  • Chemical genomics