Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Workshop: Apomixis
            

APOMIXIS TECHNOLOGY DEVELOPMENT: STRATEGIES TO GENERATE ELEMENTS OF APOMIXIS IN SEXUAL MODEL SYSTEMS.

¹ Institute for Plant Biology, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland

² CINVESTAV Plant Biotechnology Unit, CP 36500 Irapuato, México.

The development of apomixis technology in crop plants is a desirable goal. Naturally occurring apomicts derive their asexual reproductive mode from three major elements of apomixis. These are (i) the absence or alteration of meiosis preventing reduction (apomeiosis), (ii) the activation of the egg cell to form an embryo in the absence of fertilization (parthenogenesis), and (iii) the initiation of endosperm development (either autonomously or pseudogamously). The development of functional endosperm in pseudogamous apomicts relies on specific alterations of embryo sac development and fertilization or the circumvention of seed abortion due to parental effects (e.g. imprinting barriers). Apomictic development can be considered as a short-circuiting or deregulation of key stages of the sexual developmental program. Because apomixis and sexual reproduction are closely interrelated, a better understanding of the genetic and molecular basis of sexual reproduction will provide new insights for the development of apomixis technology. We use Arabidopsis as a model for a multifaceted effort to identify genes and regulatory elements that can be used as molecular tools for engineering elements of apomixis in sexual plants. We have used the enhancer detection system developed by Sundaresan et al. (Genes & Dev. 9: 1997) to identify genes and regulatory elements specific to developmental cells, tissues or stages where deregulation of the sexual developmental program is likely to occur in apomicts. An overview of these screens will be presented. A major focus has been the elucidation of the molecular mechanisms of genomic imprinting, which will allow imprinting barriers to the introduction of apomixis into sexual cereals to be overcome. Over the longer term, the combined molecular and genetic approaches described will facilitate the engineering of apomixis technology in sexual crop plants.