Claus Tittiger

We use functional genomics, molecular biology, and biochemical techniques to understand bark beetles and their interactions with host trees.  We are concentrating on two areas: the enzymes involved in isoprenoid pheromone biosynthetic pathways and the ability of the beetle to metabolize toxic resin components.

Pine bark beetles, while physically very small, can kill vast areas of coniferous forest during outbreak conditions. The increased forest fire risk and loss of timber are significant economic costs associated with bark beetle activity. Research in my lab focuses on understanding various aspects of the bark beetles’ biochemistry in order to better develop targeted control strategies. Our long term goal is to specifically regulate bark beetle populations, at least in an urban setting, without harming non-target organisms. There are two broad subject areas under study:

Pheromone Biosynthesis:Bark beetle outbreaks are mediated by aggregation pheromones, many of which are monoterpenes.  Since de novo monoterpene synthesis in the Metazoa is rare, the pheromone biosynthetic pathway is an attractive target for eventual control strategies.  Monoterpenoid pheromone components are synthesized in the midgut via the mevalonate (isoprenoid) pathway, with carbon likely being shunted away from the mevalonate pathway and into the pheromone pathway at geranyl diphosphate.

 

Phloem Detoxification:   Pine trees are full of toxic resin, which discourages animals from eating them.  The resin contains mostly monoterpenoid solvents  --turpentine and Pinesol are produced from pine trees-- and considering that drinking a medium-sized glass of turpentine is enough to kill most humans (not recommended, don’t try it!), it is remarkable that bark beetles can thrive in their environment.  Since different beetle species are more or less restricted to their host tree species, their detoxification processes are probably “tuned” to their host tree.  We are trying to understand the biochemical mechanisms the beetles use to survive constant monoterpene ingestion.

• BCH 405-605 - Molecular Biology (supported by WebCampus)