Master Project in the Department of Molecular Ecology

Project description:

Plants must defend themselves against a myriad of herbivores attacking in different ways, over different spatial scales and with more or less severe consequences for the plant’s Darwinian fitness. Plants deploy morphological or chemical defense mechanisms to repel, starve or kill herbivores and attract natural enemies of herbivores. Herbivores evolve mechanisms to counter plants’ defense mechanisms. It is therefore advantageous to plants must if they can recognize the specific attacker in order to activate optimal defense mechanisms. One of the best studied systems for plant-insect interactions is the native tobacco species Nicotiana attenuata Torr. Ex. Wats and its specialized herbivore, the tobacco hornworm Manduca sexta (Lepidoptera, Sphingidae). Nicotiana attenuata (coyote tobacco) is a wild tobacco native to the Great Basin Desert in the USA (Goodspeed 1954). It belongs to the family of Solanaceae (nightshades), one of the most widespread families in the plant kingdom with about 2500 species. Many solanaceous plants are used for their pharmacological and nutritional qualities, for example potato (Solanum tuberosum), pepper (Capsicum annuum), Datura (Datura spp.). Nicotiana attenuata produces various defense chemicals in response to attack from its specialist herbivore, Manduca sexta. Some of these defense compounds are 17-hydroxygeranyllinalool diterpene glycosides (HGL-DTGs).>

Hydroxygeranyllinalool (HGL)-DTGs consist of a acyclic C20 17-hydroxygeranyllinalool skeleton conjugated to sugar groups (glucose and rhamnose) via bonds at C-3 and C-17 hydroxylated carbons; these sugars are conjugated to the C’-2, C’-4 or C’-6 hydroxyl groups and malonyl groups which are typically connected to the C’-6-hydroxyl group of the glucose(s). HGL-DTGs have been isolated from many members of the Solanaceae including tobacco (Nicotiana spp.). HGL-DTGs are abundant secondary metabolites that occur in concentrations equivalent to starch (mg/g Fresh weight) in aboveground tissue of N. attenuata whose biosynthetic steps of glycosylation and malonylation are regulated by the defense phytohormon jasmonic acid [1]. HGL-DTGs act as potent anti-herbivore defenses.

The aim of this Master/Diploma project is to isolate an identify novel and already know HGL-DTGs for a full characterization via mass spectrometry (MS) and nuclear magnetic resonance (NMR) in N. attenuata and N. cavicola.

We are looking for motivated and reliable Master/Diploma students (natural product chemistry/analytical chemistry/biology/ biotechnology/ biochemistry/ botany) having strong interests in plant secondary metabolite identification and characterization.

Methods involved in the proposed project:

  • Identification of novel compounds and structure elucidation of secondary metabolites via FPLC, HPLC, MS and NMR
  • Mass spectrometric characterization via high resolution mass spectrometry U(H)PLC-ESI-TOF/MS, U(H)PLC-ESI-qTOF/MS
  • Method development via HPLC-UV and ESI-Q3-MS

 

Duration: 6-12 months

Contact:
Sven Heiling
Department of Molecular Ecology
Max Planck Institute for Chemical Ecology
Hans-Knöll-Straße 8
D-07745 Jena
sheiling [at] ice.mpg.de