Repeated evolution of a plant defense strategy – insights in the evolutionary machinery
The defense against herbivores is a central interface that led to the origin of a vast diversity of secondary plant metabolites. Pyrrolizidine alkaloids (PAs) are a class of metabolites that are toxic and that have an impact on animal nutrition. Some insects developed strategies not only to cope with the chemical plant defense, but also to use these toxins for their own benefit.
Current data suggest that the biosynthetic pathway of PAs was invented several times independently during angiosperm evolution. Therefore, PAs are described to occur in plant families as diverse as the daisy family (Asteraceae) or the orchids (Orchidaceae). This parallel evolution of the biochemical capacity allows comparative analyses of the pathway in different plant lineages to elucidate the mechanisms that acted during evolution. As the first specific step of this pathway is well characterized, further enzymes of this pathway are under study to answer the question how a complete pathway could evolve and how this was integrated into the already existing plant metabolism. As part of the project we will study plant lineages in which this pathway evolved already a long time ago in comparison to lineages, in which the pathway is just establishing.
We offer an array of various methods for your scientific repertoire, such as natural compound analyses, biochemical studies of enzyme activities, standard molecular techniques, and phylogenetic/bioinformatic tools to study sequence evolution.