From canonical to new model systems: The future of plant development
Bozhkov, Peter .
Norway spruce:A colossal organism to study fine processes.
The Norway spruce (Picea abies) is one of the most widely growing conifers, and is also one of the most economically important tree species in Europe. It is used for timber and paper production, as an ornamental tree in parks and gardens, and as a Christmas tree. Norway spruce played a crucial role in my scientific career and I stay devoted to it till today since after late 80s when I began to develop biotechnological methods for mass clonal propagation of this tree species. It turned out that cultured somatic cells of Norway spruce, just like carrot cells, could readily re-differentiate to form embryos. This opened possibilities to employ the process of somatic embryogenesis in forest breeding and biotechnology to mass propagate and cryopreserve elite genotypes and to shorten breeding cycle. On the other hand, we observed that somatic embryos of Norway spruce develop similar to zygotic embryos and the entire process of somatic embryogenesis can be synchronized by specific hormonal treatments. These features, together with feasibility to obtain transgenic embryogenic lines, made us to believe that somatic embryogenesis of Norway spruce can be used as a model system to address molecular mechanisms of multicellular patterning in gymnosperms and higher plants in general. An early embryo of spruce is composed of proliferating embryonal mass on the apical pole connected to the massive terminally-differentiated suspensor. While embryonal mass gives rise to plant, the suspensor functions during a brief period as a conduit of growth factors to the developing embryonal mass, but is not required at the later stages and therefore eliminated, demonstrating the earliest manifestation of programmed cell death (PCD) in plant life cycle. In the late 90s we have found that there is a gradient of successive stages of PCD along apical-basal axis of the early embryos. This gradient begins from living cells in the embryonal mass, followed by cells committed to death in the first layer of suspensor, and then continues along suspensor featuring successive stages of cell dismantling towards the basal end of the embryo where the hollow walled corpses of suspensor cells are located. In this way Norway spruce embryos have become one of the most fascinating cell-death paradigms and one of the best-understood models for studying mechanisms of developmental PCD in plants. During my talk I will present key molecular mechanisms of plant PCD that were recently discovered using Norway spruce as a model organism.
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1 - Uppsala BioCentre, Swedish University of Agricultural Sciences and Lin, Department of Plant Biology and Forest Genetics, Box 7080, Uppsala, SE-75007, Sweden
Programmed cell death.
Presentation Type: Symposium or Colloquium Presentation
Location: Delaware A/Hyatt
Date: Wednesday, July 11th, 2012
Time: 1:45 PM