Dr Karine Myriam David

PhD

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Senior Lecturer

Research | Current

The hormone signalling 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.

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.


Current projects

  1. 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 (www.isv.cnrs-gif.fr/veranglais/research/cra/cra.html).
    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.
     
  2. 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 to understand the mechanisms controlling cell expansion during apple fruit development to eventually improve the quality of fruit texture. We are also investigating how different hormones affect ripening in kiwifruit. These projects are developed in collaboration with Dr R. Schaffer (Plant and Food Research) and AP John Ross (University of Tasmania, Australia).

    Apple_cells_IAA_300px
    Effect of different IAA concentrations on apple cortex cell size. (C: Control)

     

    Auxin perception through the plasma membrane receptor

    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 signalling. We investigate the function of the ABP1 protein in Arabidopsis thaliana. We aim to (i) identify the proteins interacting with ABP1 at the plasma membrane and (ii) identify proteins/genes acting downstream of ABP1. This project is done in collaboration with Dr Rechenmann in France (CNRS).

    resized__500x323_auxin

Lab members' research

  • Nicky Read (Summer student): ABP1 signalling in Arabidopsis
  • Sam O'Donnell (Summer student): Analysis of cell wall defect in abp1 mutant
  • Ling Hong (MSc student): Characteristion of MADS8-overexpressing apple
  • Wendy Payne (Teaching technician)
  • Rosemary Bellamy (honorary research fellow) – Analysis of abp1 knock out mutants in Physcomitrella patens

Postgraduate supervision

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

Areas of expertise

Plant Molecular Science

Selected publications and creative works (Research Outputs)

  • Kinzurik, M. I., Ly, K., David, K. M., Gardner, R. C., & Fedrizzi, B. (2016). The GLO1 Gene Is Required for Full Activity of O -Acetyl Homoserine Sulfhydrylase Encoded by MET17. ACS Chemical Biology10.1021/acschembio.6b00815
    Other University of Auckland co-authors: Bruno Fedrizzi
  • McAtee, P. A., Richardson, A. C., Nieuwenhuizen, N. J., Gunaseelan, K., Hoong, L., Chen, X., ... Schaffer, R. J. (2015). The hybrid non-ethylene and ethylene ripening response in kiwifruit (Actinidia chinensis) is associated with differential regulation of MADS-box transcription factors. BMC plant biology, 15
    Other University of Auckland co-authors: Robert Schaffer
  • Schaffer, R. J., Crowhurst, R. N., Hallett, I. C., Atkinson, R. G., Bulley, S. M., Montefiori, M., ... Allan, A. C. (2015). A Genomics Approach to Understanding Fruit Characters. Paper presented at 8th International Symposium on Kiwifruit, Dujiangyan, PEOPLES R CHINA. 18 September - 22 September 2014. VIII INTERNATIONAL SYMPOSIUM ON KIWIFRUIT. (pp. 7).
    Other University of Auckland co-authors: Robert Schaffer, Andrew Allan
  • Karlova, R., Chapman, N., David, K., Angenent, G. C., Seymour, G. B., & de Maagd, R. A. (2014). Transcriptional control of fleshy fruit development and ripening. Journal of Experimental Botany, 65 (16), 4527-4541. 10.1093/jxb/eru316
  • Rae, G. M., Uversky, V. N., David, K., & Wood, M. (2014). DRM1 and DRM2 expression regulation: potential role of splice variants in response to stress and environmental factors in Arabidopsis. Molecular Genetics and Genomics, 289 (3), 317-332. 10.1007/s00438-013-0804-2
  • Ireland, H. S., Yao, J.-L., Tomes, S., Sutherland, P. W., Nieuwenhuizen, N., Gunaseelan, K., ... Schaffer, R. J. (2013). Apple SEPALLATA1/2-like genes control fruit flesh development and ripening. Plant J, 73 (6), 1044-1056. 10.1111/tpj.12094
    Other University of Auckland co-authors: Robert Schaffer
  • Rae, G. M., David, K., & Wood, M. (2013). The Dormancy Marker DRM1/ARP Associated with Dormancy but a Broader Role In Planta. Developmental Biology Journal, 2013, 1-12. 10.1155/2013/632524
  • Schaffer, R. J., Ireland, H. S., Ross, J. J., Ling, T. J., & David, K. M. (2013). SEPALLATA1/2-suppressed mature apples have low ethylene, high auxin and reduced transcription of ripening-related genes. AoB Plants, 510.1093/aobpla/pls047
    Other University of Auckland co-authors: Robert Schaffer