PhD Thesisstarted in Jul 2010
Specificity and dynamics of the firebug-Coriobacterium symbiosis
Friedrich-Schiller-Universität Jena, Biologisch-Pharmazeutische Fakultät
First Supervisor: Dr. M. Kaltenpoth
Co-Supervisor(s): Dr. H. Vogel, Prof. J. Gershenzon “First forms minute, unseen by spheric glass,
Move on the mud, or pierce the watery mass;
There, as successive generations bloom,
New powers acquire, and larger limbs assume”
-Erasmus Darwin, “The Temple of Nature” (1802)
Symbiotic interactions are an integral source for the acquisition of novel traits and adaptations. However, despite the ubiquity of mutualisms and the increasing evidence of their ecological and evolutionary importance, the role of these partnerships in fueling adaptive radiation has been largely under-explored, at least quantitatively.
For my doctoral thesis, I aim to examine symbiont-mediated evolutionary diversification in the phytophagous insect family Pyrrhocoridae (Hemiptera) through functional assays aimed at elucidating the role of the dominant microbial partners that are consistently shared across the 300 known species of this family.
Recent characterization of the gut microbiota of the red firebug (Pyrrhocoris apterus), the African cotton stainer (Dysdercus fasciatus), as well as a number of pyrrhocorid species, revealed a distinct microbiota consisting of facultative and obligate anaerobes including Actinobacteria (Coriobacterium glomerans and Gordonibacter sp.), Firmicutes (Clostridium sp. and Lactococcus lactis) and Proteobacteria (Klebsiella sp. and a previously undescribed Rickettsiales bacterium) (Sudakaran et al., 2012; Salem et al., 2012).
Elimination of the symbionts by egg surface sterilization resulted in significantly higher mortality and reduced growth rates, indicating that the microbial community plays an important role for host nutrition and development. Community level analyses targeting the dominant bacterial strains allowed us to exclusively link the observed fitness effects to the abundance of the two actionbacterial symbionts, C. glomerans and Gordonibacter sp. (Salem et al., 2012). To elucidate the exact functions of C. glomerans and Gordonibacter sp. towards their hosts, additional approaches examining the metabolism, physiology and genomic signatures of these symbionts are currently underway.
Our current findings, coupled with the reports on the feeding biology of pyrrhocorid bugs, shed light on a rare nutritional mutualism with Actinobacteria that may have enabled this insect family to exploit Malvales plants as a food source and possibly occupy and diversify in this ecological niche.
| | last updated on 2013-01-30 |
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