saha3768

 Dr. Sabine Hänniger

   
   Department of Entomology
 Phone:+49 (0)3641 57 1516Max Planck Institute for Chemical Ecology
 Fax:+49 (0)3641 57 1502Hans-Knöll-Straße 8
  emailD-07745 Jena

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Master projects, Bachelor projects and Internships possible!

Please contact me!



Current project:

Never too late to mate? -
Evolution of timing of attraction as a driver of species diversification


Virtually all life on earth experiences the same rhythmic change of day to night and the environmental changes connected to it, e.g. light intensity, temperature, predators, availability of food and mating partner. Thus processes of life, like the sleep-wake cycle, occur with circadian (circa = about, and dia = day) periodicity in most organisms, which allows them to predict the rhythmic changes in the environment. Some species have evolved to be day-active, while others are night-active. Even closely related species living in the same habitat can differ from each other in their daily activity rhythms.
The scientific community has recently acknowledged the importance of (understanding) the molecular basis of the inner clock by awarding the 2017 Nobel Prize in Physiology or Medicine jointly to Jeffrey C. Hall, Michael Rosbash and Michael W. Young for their discoveries of molecular mechanisms controlling the circadian rhythm.

Despite this growing recognition and knowledge on the molecular basis of circadian rhythms, the evolution of differentiation in daily activity patterns is largely unexplored. In insects, there are many examples of timing differentiation, and in some cases it prevents gene flow between populations. If gene flow between populations is inhibited, genetic differences may be fixed within the populations which can result in the formation of new species. By determining the genetic basis of allochronic differentiation between closely related species, or even between divergent populations within species, the initial steps causing differentiation in daily activity rhythms can be discovered, which is important for an understanding of the evolution of circadian rhythms on a micro-evolutionary time-scale.

The noctuid moth Spodoptera frugiperda is an ideal system to study the evolution of differentiation in daily activity patterns and how this differentiation drives divergence between populations. This species consists of two strains which co-exist in sympatry, the so-called corn-strain and rice-strain. The strains are morphologically indistinguishable, yet show genetic differentiation and are hypothesized to undergo speciation in sympatry. The two strains are prevented from merging into one homogeneous population, but how? Three major phenotypic differences have been described which potentially act as isolation barriers: differential host plant usage (i.e. the corn-strain feeding on taller grasses like corn and the rice-strain feeding on smaller grasses like pasture or rice), differential sexual communication and differentiation in daily rhythm, with the differentiation in daily rhythms seeming to be the strongest isolation barrier between the two strains. Therefore, my project aims to identify and characterize the genetic basis of the most consistent isolation barrier between the two S. frugiperda strains, the differentiation in daily rhythms.

I will

  • Determine the temporal isolation present in the field by quantifying differences in timing of behavior and circadian rhythm genes in different populations

  • Identify the gene(s) underlying the strain divergence in timing, by using male-informative backcrosses to construct a fine-scale linkage map and mapping the genes determining the circadian rhythm

  • Compare the expression profiles of clock genes between males and females

  • Functionally characterize candidate genes identified from the fine-scale mapping by CRISPR/Cas9 to determine their role in in the timing of sexual activities


Previous project:

Deciphering an insect-microbe interaction

using CRISPR/Cas9


The noctuid moth Spodoptera littoralis is a generalist able to feed on a large variety of plant families. Upon feeding, it encounters a huge variety of microbes. Yet, the microbial gut community of the insect mainly varies between life stages of the insect and only depends very little on the microbes encountered on different diets. This indicates that S. littorals is able to control its gut microbiome.

The metabolite 8-HQA is found in the gut of noctuid larvae and is hypothesized to be involved in the control of the gut microbiome. I used CRISPR/Cas9 genome editing to knock out genes from the biosynthetic pathway of 8-HQA and established a stable line of S. littoralis not producing 8-HQA.

Furthermore, I studied the eye and wing color changes that occurred in the knock-out mutants.


(Co-)Supervision


  • 2018 Seminarfacharbeit N. Böhmer, V. Sälzer, T. Ehrhardt (Ernst-Abbe-Gymnasium Jena)
    Nur noch Insekten im Kühlschrank? – Entomophagie als Lebensgrundlage

  • 2018 Master thesis Gözde Güney (Ankara University)
    Fat metabolism in Colorado potato beetles

  • 2018 Bachelor thesis Cansu Doğan (Ankara University)
    Livers of Insects: The fat body, structure and functions

  • 2018 Mphil thesis Djima Koffi (University of Ghana)
    Occurrence and distribution of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) and similar moths on maize in Ghana

  • 2017 Bachelor thesis Maud Hulswit (University of Amsterdam)
    The vrille protein sequence significantly differs between diurnal
    and nocturnal Lepidoptera


  • 2017 Bachelor thesis Elianne van der Valk (University of Amsterdam)
    Vrille expression involvement in mating activity differences in Lepidoptera

  • 2012 Diploma thesis André Busch (Johannes-Gutenberg-Universität Mainz)
    Differential gene expression in pheromone glands of Spodoptera frugiperda strains

Methods


  • Genome editing using CRISPR/Cas9

  • Manual Gene annotation

  • Molecular methods: Population genetic analysis and QTL analysis using AFLP markers, strain diagnosis of S. frugiperda individuals using mitochondrial markers (CO1) and restriction enzymes, strain diagnosis via SNP identification in Sanger sequences of Tpi gene in S. frugiperda, RAD sequencing of S. frugiperda QTL backcrosses, RACE PCR, qPCR, gene walk

  • Bioassays: Observation of mating and oviposition behaviour, larval performance, larval preference (choice/ no choice), oviposition choice (whole plants, plant parts), attraction to synthetic plant odors in the field and in the wind tunnel

  • Volatile collection in lab and field using SuperQ and PoraQ volatile collection traps, analysis with GC-EAD, GC-MS

  • Electrophysiology: GC-EAD, EAG

Collaborators


Dr. Stefan Bartram, MPICE, Department of Bioorganic Chemistry, Jena, Germany

Dr. Jehangir Bhadha, University of Florida, EREC, Belle Glade, FL, USA

Dr. Georg Goergen, IITA Cotonou, Benin

Prof. Dr. Astrid Groot, University of Amsterdam, the Netherlands

Dr. María Laura Juárez, CCT-CONICET-TUCUMAN, San Miguel de Tucumán, Argentina

Djima Koffi, University of Ghana

Tilottama Mazumdar, MPICE, Department of Bioorganic Chemistry, Jena, Germany

Dr. Rob Meagher, USDA-ARS Gainesville, FL, USA

Dr. Michael Reichelt, MPICE, Department of Biochemistry, Jena, Germany

Dr. Hannah Rowland, MPICE, Max Planck Research Group Predators and Prey, Jena, Germany

Dr. Melanie Unbehend, MPICE, Department of Entomology, Jena, Germany

Dr. Tom Walsh, CSIRO Canberra, Australia

Dr. Jörg Wennmann, Julius Kühn-Institut, Darmstadt, Germany
last updated on 2018-10-10