My main research interest is the ecology and evolution of fluorescent pseudomonads. Fluorescent pseudomonads form an ubiquitous taxon that colonizes plant roots and protect the host plant against soil borne pathogens by producing antifungal toxins. They present thus a great potential as biological control agent in the agriculture, as alternative to fungicides.
My work aims at understanding how biotic interactions drive the fitness and activity of rhizosphere bacteria. Bacteria are in intense competion for resources (soil minerals and plant-derived exudates), and have to evade predation by protozoa and nematodes. Bacteria can defend themselves by producing broad spectrum anti-eukaryotic toxins that will repel or inhibit the predators. Interestingly, the same toxins helping bacteria to resist predation also inhibit plant pathogens, and intense predation may promote plant protecting bacterial populations.

I use Pseudomonas fluorescens as model bacterial species to investigate these biotic interactions.

My research covers the following aspects:

• Effect of biodiversity on the performance and evolution of microbial communities
  
• Effect of secondary metabolites on the interaction between bacteria and microfaunal predators.
  
• Chemical communication between biocontrol bacteria and surrounding microorganisms and plants
  

Publications

1. Friman, VP., Jousset, A., Buckling, A. Rapid prey evolution can alter the structure of predator-prey communities. Journal of Evolutionary Biology (accepted)

2. Jousset, A., Becker, J., Chatterjee, S., Karlovsky, P., Scheu, S., Eisenhauer, N. Biodiversity and species identity shape the antifungal activity of bacterial communities. Ecology in press

3. Jousset, A., Eisenhauer, N., Materne, E., Scheu, S. (2013): Evolutionary history predicts the stability of cooperation in microbial communities. Nature Communications 4:2573.

4. Müller, MS., Scheu, S., Jousset, A. (2013): Protozoa drive the dynamics of culturable biocontrol bacterial communities. PLoS ONE 8: e66200

5. Li, M., Huang, WE., Gibson, CM., Fowler, PW., Jousset, A. (2013): Stable isotope probing and Raman spectroscopy for monitoring carbon flow in a food chain and revealing metabolic pathway. Analytical Chemistry 85: 1642−1649.

6. Eisenhauer, N., Schulz, W., Scheu, S., Jousset, A. (2013): Niche dimensionality links biodiversity and invasibility in microbial communities. Functional Ecology 27:282-288.

7. Becker, J., Eisenhauer, N., Scheu, S., and Jousset, A. (2012) Increasing antagonistic interactions cause bacterial communities to collapse at high diversity. Ecology Letters 15: 468-474. (rated “2 stars” by Faculty of 1000)

8. Eisenhauer, N., Scheu, S., and Jousset, A. (2012) Bacterial diversity stabilizes community productivity. PLoS ONE 7: e34517.

9. Jousset, A. (2012) Ecological and evolutive implications of bacterial defences against predators. Environmental Microbiology 14:1830-1843.(Invited review)

10. Latz, E., Eisenhauer, N., Rall, B.C., Allan, E., Roscher, C., Scheu, S., and Jousset, A. (2012) Plant diversity improves protection against soil-borne pathogens by fostering antagonistic bacterial communities. Journal of Ecology 100: 597-604.(Notebook article in “The Scientist”)

11. Henkes, G., Jousset, A., Bonkowski, M., Thorpe, M.R., Scheu, S., Schurr, U., and Röse, U.S.R. (2011) Pseudomonas fluorescens CHA0 maintains carbon delivery to Fusarium graminearum infected roots and prevents reduction in biomass of barley shoots through systemic interactions. Journal of Experimental Botany 62: 4337-4344.

12. Jousset, A., Rochat, L., Lanoue, A., Keel, C., Bonkowski, M., and Scheu, S. (2011) Plants respond to pathogen infection by enhancing the antifungal activity of root-associated bacteria. Molecular Plant-Microbe Interactions 24: 352-358.

13. Jousset, A., Schmid, B., Scheu, S., and Eisenhauer, N. (2011) Genotypic richness and dissimilarity opposingly affect ecosystem performance. Ecology Letters 14: 537-624 (cited in various German newspapers including die Welt, Göttinger Tagesblatt, Berliner Morgenpost)

14. Jousset, A., Schulz, W., Scheu, S., and Eisenhauer, N. (2011) Intraspecific genetic richness and relatedness predict the invasibility of bacterial communities ISME Journal 5: 1108-1114. (Research Highlight in Nature Reviews Microbiology 9:312-313)

15. Neidig, N., Paul, R., Scheu, S., and Jousset, A. (2011) Secondary metabolites of Pseudomonas fluorescens CHA0 drive complex non-trophic interactions with bacterivorous nematodes. Microbial Ecology 61: 853-859.

16. Jousset, A., and Bonkowski, M. (2010) The model predator Acanthamoeba castellanii induces the production of 2,4- DAPG by the biocontrol strain Pseudomonas fluorescens Q2-87. Soil Biology & Biochemistry 42: 1647-1649.

17. Jousset, A., Rochat, L., Scheu, S., Bonkowski, M., and Keel, C. (2010) Predator-prey chemical warfare determines the expression of antifungal genes by rhizosphere pseudomonads. Applied and Environmental Microbiology 76: 5263-5268. (rated “9 ” by Faculty of 1000)

18. Neidig, N., Jousset, A., Nunes, F., Bonkowski, M., Paul, R.J., and Scheu, S. (2010) Interference between bacterial feeding nematodes and amoebae relies on innate and inducible mutual toxicity Functional Ecology 24: 1133-1138.

19. Jousset, A., Lara, E., Nikolausz, M., Harms, H., and Chatzinotas, A. (2009) Application of the denaturing gradient gel electrophoresis (DGGE) technique as an efficient diagnostic tool for ciliate communities in soil. Sci Total Environ 408: 1221-1225.

20. Jousset, A., Rochat, L., Keel, C., Pechy-Tarr, M., Scheu, S., and Bonkowski, M. (2009) Predators promote toxicity of rhizosphere bacterial communities by selective feeding on non-toxic cheaters. ISME Journal 3: 666-674.(Research Highlight in Nature Reviews Microbiology 7:326-327)

21. Schebb, N.H., Vielhaber, T., Jousset, A., and Karst, U. (2009) Development of a liquid chromatography-based screening methodology for proteolytic enzyme activity. Journal of Chromatography A 1216: 4407-4415.

22. Jousset, A., Scheu, S., and Bonkowski, M. (2008) Secondary metabolite production facilitates establishment of rhizobacteria by reducing both protozoan predation and the competitive effects of indigenous bacteria. Functional Ecology 22: 714-719.

23. Jousset, A., Lara, E., Wall, L.G., and Valverde, C. (2006) Secondary metabolites help biocontrol strain Pseudomonas fluorescens CHA0 to escape protozoan grazing. Applied and Environmental Microbiology 72: 7083-7090.