Robert Verpoorte – författare

To date, several possibilities exist to change the genetics of plants including classical breeding and modern molecular biological approaches such as recombinant DNA techniques and plant trans­ formation methods. The aim of this publication is to review the feasibilities, offered by the current technologies, to modify flower colours. Due to the great importance of anthocyanins as flower pigments, the main part of this study deals with this class of flavonoids responsible for most red-, purple- and blue colours. Being electron deficient, the flavylium nucleus of the anthocyanins is highly reactive and undergoes - dependent upon pH - readily structural transformations which are coupled with colour changes. A number of mechanisms that stabilizes the coloured - at expense of the colourless structures in plants are described, including acylation, co pigmentation and metal complex formation. Because no plant species possesses the genetic capacity for producing varieties in the full spectrum of colours, man has looked for methods to change the genetic properties of plants. In recent years, conventional flower breeding is more and more being supplemented by genetic engineering techniques. This technology offers the possibility to insert specific genes into the cell genome and to transfer genes most efficiently between different organisms. The common flower pigments, the anthocyanins, have been studied for many years and represent now the best understood group of secondary plant metabolites with respect to (bio)chemistry and genetics.

Since 1984 and 1988, when meetings were held on the topic of primary and secondary metabolism of plant cell cultures, there has been a clear shift of the focus of ongoing research. While the cell culture itself and the production of secondary metabolites and the biosynthetic pathways and the activity of enzymes were major topics, now these aspects are linked with genes, i.e. molecular biology becomes more prominent. This book has contributions on such subjects as fermentation, enzymology of secondary metabolism, catabolism of secondary metabolites, elicitation of pathways and genetic modification of metabolic pathways. It includes contributions on the most recent achievements in the research on among other things tropane and indole alkaloids, phenolics, (iso)flavonoids, terpenes and cardenolides. It should be a useful review of the progress made in the past years and a perspective on the future developments.