Dr. Arunika Nishanthi Gunawardena

ASSOCIATE PROFESSOR
BSc (Peradeniya, Sri Lanka, 1993)
PhD (Oxford Brookes, UK, 2000)
Postdoc (Toronto, Canada, 2002-2006)


  • Teaching & Research
  • Graduate Studies
  • Publications 
  • Links
  • Teaching & Research
    programmed cell death, apoptosis, lace plant, Aponogeton madagascariensis, plant development, cell biology, perforation formation, caspases, ethylene, developmental PCD

    My research interest is programmed cell death (PCD) in plant development. The development of complex leaf shape through perforation formation is a unique and fascinating use of developmental PCD. Several Monstera species (Araceae) and a single species of the distantly related Aponogeton family,

    Aponogeton madagascariensis (lace plant) are the only vascular plants that form perforations by PCD during leaf development. Lace plant is native to Madagascar where it grows in river habitats as a submerged aquatic. Mature leaf blades are highly unusual in that they are perforated with holes that extend through the blade, forming an open lattice pattern. Perforations are positioned equidistantly between the longitudinal and transverse veins, and are large and rectangular near the midvein, but smaller and rounder near the margin. Immature leaves are rolled longitudinally, but unfurl as they expand from the apical region of the corm-like tuber to form a flat leaf blade with a simple shape. Young leaves are red in color due to anthocyanin which disappears as they mature (Figures 1-3).

    PCD is initiated in a population of cells at the center of the perforation site, and then is propagated outward through epidermal and mesophyll cells until it reaches tissue that is about 5 cells from the veins. This spatial pattern makes it possible to predict which cells are going to die and to identify adjacent cells of the same age that will not undergo the PCD process.

    Classes in which Arunika currently teaches
  • Biology 2004: Diversity of Life II
  • Biology 4220/5220: Plant Cell Biology
  • The accessibility and predictability of perforation formation in aquatic lace plant provides an extremely tractable system in which to study the process of PCD, as well as its developmental control

    Although some of the steps of cell death execution have been identified in this unique case of developmentally-regulated PCD in plants, nothing is known about the developmental cues, signaling pathways, or molecular regulation of the PCD process during perforation formation. Therefore, my research goals are:

    1. To test the hypothesis that ethylene is an inductive candidate signal of PCD
    2. To test the effect of inhibitors of caspase enzymes on cell death in plants
    3. To use molecular markers to characterize key events of PCD in living cells
    4. To identify genes involved in PCD in lace plant perforation formation using laser capture microdissection (LCM) and differential display techniques

    GRADUATE  STUDIES:

    Currently accepting applications from undergraduate and postgraduate students to undertake the above projects.

     


    Selected Publications

    Lord, C, Wertman, J., Lane, S. and Gunawardena, A.H.L.A.N. (2011). Do mitochondria play a role in remodelling lace plant leaves through programmed cell death?” BMC Plant Biology doi:10.1186/1471-2229-11-102.

    Carter, J. and Gunawardena, A.H.L.A.N. (2011). Regeneration of the aquatic monocot Aponogeton madagascariensis (lace plant) through callus induction. Aquatic Botany 94: 143–149.

     Lord, C., and Gunawardena, A.H.L.A.N (2011). Environmentally induced programmed cell death in leaf protoplasts of Aponogeton madagascariensis. Planta 233: 407-421.

    Lord, C., and Gunawardena, A.H.L.A.N (2010). Isolation of leaf protoplasts from the submerged aquatic monocot Aponogeton madagascariensis. The Americas Journal of Plant Science and Biotechnology 4 (Special issue 2), 6-11.

    Elliott, A. and Gunawardena, A.H.L.A.N. (2010). Calcium inhibition halts developmental programmed cell death in the lace plant, Aponogeton madagascariensis? Botany 88: 206-210.

    Wright, H., van Doorn W.G, Gunawardena, A.H.L.A.N. (2009). In vivo study of developmental programmed cell death using the lace plant (Aponogeton madagascariensis; Aponogetonaceae) leaf model system. American Journal of Botany 96(5): 865-876. Cover image by Harrison Wright.

    Gunawardena A.H.L.A.N. (2008) Programmed cell death and tissue remodeling in plantsJournal of Experimental Botany 59: 445 – 451. 

    Urquhart, W., Gunawardena, A.H.L.A.N., Moeder, W., Ali, R., Berkowitz, G.A., and Yoshioka, K. (2007). The chimeric cyclic nucleotide-gated ion channel ATCNGC11/12 constitutively induces programmed cell death in a Ca2+ dependent manner. Plant Molecular Biology 65: 747-761.

    Gunawardena, A.H.L.A.N., Greenwood, J.S., and Dengler, N.G. (2007). Cell wall degradation and modification during programmed cell death in lace plant, Aponogeton madagascariensis (Aponogetonaceae). American Journal of Botany 94(7): 1116–1128. Cover image by Arunika Gunawardena.

    Gunawardena, A.H.L.A.N., and Dengler, N.G. (2006). Alternative modes of leaf dissection in monocotyledonsBotanical Journal of Linnean Society 150: 25-44. 

    Gunawardena, A.H.L.A.N., Greenwood J.S. and Dengler, N.G. (2005). Programmed cell death and leaf morphogenesis in Monstera obliqua.  Planta  221: 607-618. 

    Gunawardena, A.H.L.A.N., Greenwood, J.S., and Dengler, N.G. (2004). Programmed cell death remodels lace plant leaf shape during development.  Plant Cell 16: 60-73.  Cover image by Arunika Gunawardena.


    Links



    • (e-mail enabled browser is not required)
    HALIFAX, NOVA SCOTIA | CANADA B3H 4R2 | +1 (902) 494-3515