Dr Karine David

Senior Lecturer

Senior Lecturer

Plant Molecular Science

Phone: 09-3737599 x83793
Rm 110-310
Email: k.david@auckland.ac.nz

The hormone signaling group

My group is investigating the early events of auxin signalling. Auxin is one of the major plant hormone implicated in virtually every aspect of plant growth and development. Despite its established biological and agronomic importance, the molecular mechanisms underlying the auxin early response remain unclear.

auxin

We are particularly interested in the auxin extracellular receptor ABP1 (Auxin-binding protein 1), an essential membrane-bound protein that control early events in auxin signaling. We investigate the function of th ABP1 protein in 2 model systems: Arabidopsis thaliana and the moss Physcomitrella patens.

We are also interested by understanding the role of auxin during fruit development and ripening. This work is done in collaboration with Dr R. Schaffer’s group (Fruit texture and Genomics) at Plant and Food Research .

The approaches we use are multidisciplinary and combine genetic, molecular biology, biochemistry and proteomic.

Research projects in the hormone signaling lab can be based in here at the School of Biological Sciences or carried out with collaborators at Plant and Food Research (Mt Albert).

Auxin perception through the plasma membrane receptor, the Auxin Binding Protein 1 (ABP1)

We aim to (i) identify the proteins interacting with ABP1 at the plasma membrane and (ii) identify proteins/genes acting downstream of ABP1. We mainly use Arabidopsis as a plant model. Because a mutation in ABP1 gene is embryo lethal, we use conditional knock-out lines of ABP1 obtained by the group of C. Rechenmann in France (CNRS), who we have a collaboration with (http://www.isv.cnrs-gif.fr/veranglais/research/cra/cra.html).

arabidopsis Physcomitrella
We also investigate how auxin signalling pathways have evolved by studying auxin responses of the moss Physcomitrella patens. This model plant is considered as the ‘green yeast’ as it is the only plant in which targeted gene knock-out by homologous recombination is possible.

The role of auxin during apple fruit development and ripening:

Fruit texture is an important criterion affecting consumer preference. Two main factors affect this character - cell size and cell-wall rigidity. Both are partly controlled by the plant hormone auxin. We are deciphering the role of auxin during apple fruit development. We aim understand the mechanisms controlling cell expansion during apple fruit development to eventually improve the quality of fruit texture. This project is a collaboration with Dr R. Schaffer (Plant and Food Research) and AP John Ross (University of Tasmania, Australia).

Lab members


  • Nathan Deed (PhD student) – Cell expansion - What are the molecular mechanisms underlying the auxin response?
  • Georgina Rae (PhD student, co-supervised by Dr Marion Wood at PFR) – Role of dormancy associated genes DRM1 and DRM1-H in Arabidopsis thaliana
  • Thomas Doucen (French internship) – Expression analysis of early response genes during apple fruit development
  • Jeannette Keeling (technician) - Development of transient assay in fruits
  • Wendy Payne (Teaching technician) – Cell expansion in apple cell cultures
  • Rosemary Bellamy (honorary research fellow) – Analysis of abp1 knock out mutants in Physcomitrella patens

Recent Publications

M Gunl, F M Liew, David K.M., J Putterill. (2009). Analysis of a post-translational steroid induction system for GIGANTEA in Arabidopsis. BMC Plant Biology 9:141. 2009.

Braun N, Wyrzykowska J, Muller P, David K.M., Couch D, Perrot-Rechenmann C and Fleming AJ (2008). Conditional Repression of AUXIN BINDING PROTEIN1 Reveals That It Coordinates Cell Division and Cell Expansion during Postembryonic Shoot Development in Arabidopsis and Tobacco. Plant Cell, 20:2746-62.

Kim W.Y., Fujiwara S., Suh S.S., Kim J., Kim Y., Han L., David K.M., Putterill J., Nam H.G. and Somers D.E (2007). ZEITLUPE is a circadian photoreceptor stabilized by GIGANTEA in blue light. Nature, 449: 356-60.

David K.M., Couch D, Braun N, Brown S, Grosclaude J, Perrot-Rechenmann C (2007). The auxin-binding protein 1 is essential for the control of cell cycle. Plant J. 50(2):197-206.

David K.M., Couch D and Perrot-Rechenmann C (2007). Does auxin-binding protein 1 control both cell division and cell expansion?. Plant Signaling & Behavior 2(5):376-377.

David K.M., Armbruster U, Tama N, Putterill J (2006). Arabidopsis GIGANTEA protein is post-transcriptionally regulated by light and dark. FEBS Lett. 580:1193-1197.

Napier R.M., David K.M. & Perrot-Rechenmann C (2002). A short history of auxin-binding proteins. Plant Molecular Biology, 49: 339-348.

David K.M., Carnero-Diaz E., Leblanc N., Monestier M., Grosclaude J. & Perrot-Rechenmann C (2001). Conformational dynamics underlies Nt-abp1 activity. Journal of Biological Chemistry, 276: 34517-34523.

David K.M. & Perrot-Rechenmann C (2001). Characterisation of a tobacco BY2 cell line expressing the tetracycline repressor at a high level for strict regulation of transgene expression. Plant Physiology, 125: 1548-1553.

Leblanc N., David K.M., Grosclaude J., Pradier J.M., Barbier-Brygoo H., Labiau S. & Perrot-Rechenmann C (1999). A novel immunological approach establishes that the auxin-binding protein Nt-abp1 is an element involved in auxin signaling at the plasma membrane. Journal of Biological Chemistry, 274: 28314-28320.

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