A Functional Genomics Strategy to Identify Genes That Regulate the Production of Biologically Active Metabolites in Plants

Abstract

Plants produce an extraordinary range of biologically active metabolites and many of these are valuable because of their roles in human health and nutrition. A majority of these natural products are classified as “secondary” compounds, to distinguish them from the essential products of primary metabolism. These are often unique to certain plant families or species. This diversity is one of several factors that has hampered the elucidation of many secondary pathways. Regulatory properties often associated with the biosynthesis of secondary compounds, such as cell-type specific localization and transient expression, also may obscure the true biosynthetic potential of a plant. An additional impediment to studying genes involved in this diverse metabolism is that many plant species have complex genomes and are not amenable to efficient genetic techniques. The strategy described here circumvents these difficulties by applying pharmacological activity screens at the level of undifferentiated plant callus tissue. This strategy allows functional detection of compounds of pharmacological interest and offers a means for applying a functional genomics strategy to mutagenized cell cultures.