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

  • 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
  • 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   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
  • Arabidopsis BTB/POZ protein-dependent PENETRATION3 trafficking and disease susceptibility 
    Mao, Hailiang; Aryal, Bibek; Langenecker, Tobias; et al. 
    NATURE PLANTS, 3 (11): 854-858 10.1038/s41477-017-0039-z  NOV 2017
  • Plant hormone transporters: what we know and what we would like to know 
    Park, Jiyoung; Lee, Youngsook; Martinoia, Enrico; et al. 
    BMC BIOLOGY, 15: 10.1186/s12915-017-0443-x  OCT 25 2017
  • A Critical View on ABC Transporters and Their Interacting Partners in Auxin Transport 
    Geisler, Markus; Aryal, Bibek; di Donato, Martin; et al. 
    PLANT AND CELL PHYSIOLOGY, 58 (10): 1601-1614  10.1093/pcp/pcx104  OCT 2017
  • SHADE AVOIDANCE 4 Is Required for Proper Auxin Distribution in the Hypocotyl 
    Ge, Yanhua; Yan, Fenglian; Zourelidou, Melina; et al. 
    PLANT PHYSIOLOGY, 173 (1): 788-800 10.1104/pp.16.01491 JAN 2017
  • Flavonol-induced changes in PIN2 polarity and auxin transport in the Arabidopsis thaliana rol1-2 mutant require phosphatase activity 
    Kuhn, Benjamin M.; Nodzynski, Tomasz; Errafi, Sanae; et al. 
    SCIENTIFIC REPORTS, 7: 10.1038/srep41906  FEB 6 2017
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