Epidermal root cells as a suitable cell biological model system to unravel PIN2 auxin efflux carrier turnover and differential growth regulation in plants

• Applicant: Dr. David Scheuring
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2013 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 233353861

• Final Report Year: 2015

Final Report Abstract

Plant growth depends on the increase of cell numbers and the increase of cell size. In nonmotile organisms, the increase in cell size is particularly important and must be tightly regulated. One of the key regulators for plant growth is the phytohormone auxin. In the root epidermis auxin steers root organ growth. I have used the cell size difference of atrichoblasts and trichoblasts in the epidermis as a model system to dissect cell size control and, more specifically the PIN2 auxin efflux carrier turnover. We could show that these epidermal cells show complex regulations of PIN2 auxin transport, jointly contributing to root organ growth. The obtained data suggests that auxin-dependent processes, particularly in trichoblast cells, may be vital for defined gravitropic root growth. Taken together we conclude that the root epidermis indeed represents a suitable cell-biological system to investigate complex growth regulations and the integration of growth in neighbouring tissues. Interestingly, auxin does not only impact on cell size but directly on the size and morphology of a prominent cell organelle – the vacuole. Using our root epidermal model system I helped to reveal that auxin controls the morphology of vacuoles and that this correlates with auxindependent cell size regulation. The mandatory techniques to highlight the lumen as well as the membrane of the vacuole I could describe and publish. Moreover, in another first author paper, I am unraveling the importance of actin/myosin dependent processes for the auxin effect on vacuolar morphogenesis required for cellular growth control.

Publications

• Springer press: Auxin and Its Role in Plant Development. 2014; pp 61-73. Online ISBN: 978-3-7091-1526-8
  Scheuring D., and Kleine-Vehn J.
  
• Auxin regulates SNARE-dependent vacuolar morphology restricting cell size. eLife 2015; 4:e05868
  Löfke C., Dünser K., Scheuring D. and Kleine-Vehn J.
  
• Tricho- and atrichoblast cell files show distinct PIN2 auxin efflux carrier exploitations and are jointly required for defined auxin-dependent root organ growth. J Exp Bot. 2015 Jun 3
  Löfke C., Scheuring D., Dünser K., Schöller M., Luschnig C., and Kleine-Vehn J.
  
• Vacuolar staining methods in plant cells. Methods Mol Biol. 2015;1242:83-92
  Scheuring D., Schöller M., Kleine-Vehn J. and Löfke C.