A functional genomics approach toward the understanding of plant secondary metabolism: I. Transcriptomics and high-throughput functional analysis of genes in plant cells

Genetic knowledge on biosynthetic pathways and the regulation thereof is of crucial importance to bypass the low-product yield of various secondary metabolites in plant cells. To facilitate gene discovery in plant secondary metabolism, we have developed a comprehensive profiling approach that is based on functional genomics and can be applied on any plant system, without a need for prior sequence knowledge. Thus far, we have monitored jasmonate-induced changes on the transcript and alkaloid profiles of tobacco BY-2 and Catharanthus roseus cell cultures. Using cDNA-AFLP based transcript profiling, an inventory of hundreds of genes, potentially involved in plant secondary metabolism, has been built. A technology platform, especially driven towards the exploitation of plant cell suspension cultures, for high-throughput isolation and functional analysis of these genes has been established. This platform will allow creating a novel toolbox for metabolic engineering of plant cells. At present, more than 50 tobacco BY-2 full-length open reading frames have been isolated and are currently subjected to functional analysis in transgenic tobacco, Hyoscyamus muticus and C. roseus cell or hairy root lines.