Symbiosis Control

Wolbachia is an intracellular maternally inherited bacterium which is able to invade and maintain itself in numerous arthropod host species by manipulating their reproduction. These reproductive manipulations include the induction of parthenogenetic development in certain parasitic wasps, overriding chromosomal sex determination to convert infected genetic males into functional females in some isopod species, male killing and most commonly the induction cytoplasmic incompatibility (CI), a form of embryonic lethality in crosses between males and females of different Wolbachia infection status. Each of these reproductive effects favors the transmission of this maternally inherited bacterial agent often at the expense of the arthropod host. There is an increasing interest in the use of Wolbachia infections in an applied context. It has been proposed that they might be used either as a tool to drive desirable genotypes into natural populations of insects or alternatively to directly suppress insect populations. 

Relevant Wolbachia Web Pages and Information

    * Wolbachia, University of Queensland, Australia  http://www.wolbachia.sols.uq.edu.au/index.html

    * FIBR: the NSF-funded Wolbachia Project http://research.amnh.org/FIBR/  

    * The NEB-funded Wolbachia Project http://tools.neb.com/wolbachia/  

    * The European Wolbachia Project http://www.nf-2000.org/secure/FP5/S1415.htm  

All inquiries of this application are directed to Associate Professor Kostas Bourtzis at the Department of Environmental and Natural Resources Management, University of Ioannina, Greece: http://www.env.uoi.gr/dep_1.asp?id=6  

Kostas Bourtzis, Ph.D.

Associate Professor in Molecular Biology and Biochemistry

Department of Environmental and Natural Resources Management

University of Ioannina

2 Seferi Street

30100 Agrinio

Greece

Phone office: 30-26410-39514

Phone lab: 30-26410-39503

Fax: 30-26410-33716

kbourtz@cc.uoi.gr 

Dr. Bourtzis’ research aims to understand the interactions of the intracellular bacterium Wolbachia with its insect hosts. Our basic studies mainly focus on the unraveling of the mechanism of Wolbachia-induced CI using biochemical, genetic, cellular and molecular techniques as well as genomic, proteomic and bioinformatic approaches. Our research also focuses on the use of Wolbachia-induced CI towards the development of novel and environmentally friendly approaches for the control of pest and vector species of economic and health relevance.

We have recently established Wolbachia-infected lines of the medfly Ceratitis capitata, a major agricultural pest, using the infected cherry fruit fly Rhagoletis cerasi as donor. Wolbachia induced complete (100%) CI in the novel host. Our study clearly showed that Wolbachia endosymbionts can be experimentally transferred over genus barriers into a novel host, forming associations which express complete CI. In addition, laboratory cage populations were completely suppressed by single releases of infected males suggesting that Wolbachia-induced CI (unidirectional and, importantly, bidirectional) could be used as a novel and environment friendly tool for the control of natural medfly populations (see our ms: S. Zabalou, M. Riegler, M. Theodorakopoulou, C. Stauffer, C. Savakis and K. Bourtzis (2004). Wolbachia-induced cytoplasmic incompatibility as a means for insect pest population control. Proceedings of National Academy of Sciences USA, 101: 15042-15045). For effective Wolbachia-based population suppression, an efficient genetic sexing system producing males only is necessary. Such systems are available in medfly.

Altogether, our results encourage efforts to transfer Wolbachia into insect pests or disease vectors for suppression or modification of natural populations. We plan to apply the above mentioned Wolbachia-based technology to another major agricultural insect pest, the olive fly, Bactrocera oleae.

Selected Publications

   1. S. Zabalou, M. Riegler, M. Theodorakopoulou, C. Stauffer, C. Savakis and K. Bourtzis (2004). Wolbachia-induced cytoplasmic incompatibility as a means for insect pest population control. Proceedings of National Academy of Sciences USA, 101: 15042-15045. 

   2. Z. Veneti, M. E. Clark, T. L. Karr, C. Savakis and K. Bourtzis (2004). Heads or tails: host-parasite interactions in the Drosophila-Wolbachia system. Applied and Environmental Microbiology, 70: 5366-5372.

   3. S. Zabalou, S. Charlat, A. Nirgianaki, D. Lachaise, H. Merçot and K. Bourtzis (2004). Natural Wolbachia infections in the Drosophila yakuba species complex do not induce cytoplasmic incompatibility but fully rescue the wRi modification. Genetics, 167: 827-834.

   4. K. Bourtzis, H.R. Braig and T.L. Karr (2003). Cytoplasmic Incompatibility. In: K. Bourtzis, T. Miller, eds. Insect Symbiosis. CRC Press, Florida, USA, pp. 217-246.

   5. K. Bourtzis and T. Miller eds. (2003). Insect Symbiosis. CRC Press, Florida, USA, pp. 347.

   6. Z. Veneti, M.E. Clark, S. Zabalou, T.L. Karr, C. Savakis and K. Bourtzis (2003). Cytoplasmic incompatibility and sperm cyst infection in different Drosophila-Wolbachia associations. Genetics, 164: 545-552.

   7. A. Nirgianaki, G.K. Banks, D. Frohlich, Z. Veneti, H.R. Braig, T.A. Miller, I.D. Bedford, P.G. Markham, C. Savakis, and K. Bourtzis (2003) Wolbachia infections of the whitefly Bemisia tabaci. Current Microbiology, 47: 93-101.

   8. K. Bourtzis, M.M. Pettigrew and S.L. O’Neill (2000). Wolbachia neither induces nor suppresses transcripts encoding antimicrobial peptides. Insect Molecular Biology 9: 635-639.

   9. K. Bourtzis, S.L. Dobson, H.R. Braig and S.L. O’Neill (1998). Rescuing Wolbachia have been overlooked. Nature 391: 852-853.

  10. K. Bourtzis, A. Nirgianaki, G. Markakis  and C. Savakis (1996). Wolbachia infection and cytoplasmic incompatibility in Drosophila species. Genetics 144:1063-1073.