A Molecular Framework for Arabidopsis Somatic Embryogenesis


In plants, embryogenesis usually takes place in the seed after egg and sperm fusion, however this process can also be induced in vitro, either from unfertilized gametophytic cells or from the cells of vegetative tissue explants. Somatic embryogenesis, in which embryos are derived from vegetative cells of the plant, is most commonly induced by exposing explants to stress conditions and/or exogenous growth regulators. There is considerable interest in somatic embryogenesis, both as a clonal propagation tool for the green sector and as a model system for understanding plant cell totipotency. Historically more emphasis has been placed on achieving and optimising somatic embryo (SE) production in different species than on understanding the mechanism underlying SE formation. The few mechanistic studies have used "static" approaches, which has made it difficult to establish causal relationships between the observed changes and the developmental fate of individual cells. In the last decade, significant progress has been made in developing arabidopsis as a model for studies on SE. Still, there are very large gaps in our knowledge with respect to the dynamic steps needed to convert a differentiated cell into a SE. Here we propose to use a combination of cell biology, physiology and molecular and genetic approaches to identify these steps during arabidopsis somatic embryo development, and in particular, the role of auxin biosynthesis, transport and signalling, and the BBM transcription factor in this process. We will focus our efforts on the earliest stages of SE induction by the auxin analog 2,4-D in vitro, and use these results as a framework to understand the relationship between this process and BBM-mediated SE induction in planta.





Dr. R. Offringa

Verbonden aan

Universiteit Leiden, Faculteit der Wiskunde en Natuurwetenschappen, Instituut Biologie Leiden IBL


Drs. C. Philipsen


24/10/2011 tot 02/08/2016