EST Sequencing from Embryogenic Cyclamen persicum Cell Cultures Identifies a High Proportion of Transcripts Homologous to Plant Genes Involved in Somatic Embryogenesis

Abstract

To learn more about the process of somatic embryogenesis in the economically important ornamental plant Cyclamen persicum, we initiated an expressed sequence tag (EST) project. A normalized cDNA library was constructed from embryogenic cell material in different developmental stages, and clones were subsequently sequenced from the 5′ end. A total of 2083 filtered EST with an average length of 499 bases were analyzed in this study and submitted to the international sequence databases. By computational analyses, the Cyclamen transcripts were annotated and checked against plant genes previously described to be involved in somatic embryogenesis. Approximately one third of those genes were covered by the Cyclamen EST analyzed in this study. A high proportion of homologs to genes involved in somatic embryogenesis in the model system Daucus carota (carrot) were found in the Cyclamen EST collection. Of special interest are transcripts encoding gibberellin oxidases and somatic embryogenesis receptor-like kinases (SERK), both of which were confirmed to be important for development of embryos from somatic carrot cells. In addition, the set of candidate genes was expanded by using gene ontology (GO) annotations as well as by comparison with EST that were shown to be upregulated during Glycine max (soybean) somatic embryogenesis in a microarray approach. Our computational biology approach disclosed a set of around 90 candidate genes that now can be tested in the wet lab for their influence on somatic embryogenesis in Cyclamen. The annotated Cyclamen transcripts are available via http://www.Cyclamen-est.de.