Stopnisek Nejc, Zühlke Daniela, Carlier Aurélien, Barberán Albert, Fierer Noah, Becher Dörte, Riedel Katharina, Eberl Leo, Weisskopf Laure (2016), Molecular mechanisms underlying the close association between soil Burkholderia and fungi, in
The ISME Journal, 10, 253-264.
Stopnisek Nejc, Bodenhausen Natacha, Fierer Noah, Frey Beat, Eberl Leo, Weisskopf Laure (2014), Genus-wide acid tolerance accounts for the biogeographical distribution of soil Burkholderia populations, in
Environmental Microbiology, 16(6), 1503-1512.
Kost Thomas, Stopnisek Nejc, Agnoli Kirsty, Eberl Leo, Weisskopf Laure (2014), Oxalotrophy, a widespread trait of plant-associated Burkholderia species, is involved in successful root colonization of lupin and maize by Burkholderia phytofirmans., in
Frontiers in microbiology, 4, 421.
Groenhagen Ulrike, Baumgartner Rita, Bailly Aurélien, Gardiner Amber, Eberl Leo, Schulz Stefan, Weisskopf Laure (2013), Production of bioactive volatiles from different Burkholderia ambifaria strains, in
Journal of Chemical Ecology, 39(7), 892-906.
Schwager S Lumjiaktase P Stöckli M Weisskopf L and Eberl L (2012), The genetic basis of cadmium resistance of Burkholderia cenocepacia, in
Environmental Microbiology Reports, 4(5), 562-568.
Weisskopf Laure Heller Stefanie and Eberl Leo (2011), Burkholderia sp are major inhabitants of white lupin cluster roots, in
Applied and Environmental Microbiology, 77(21), 7715-7720.
Recent studies have shown that pH plays a major role in the biogeography of micro-organisms. However, the mechanisms that enable specific taxa to establish in low pH environments, while others are excluded have not yet been investigated. In this project, we address this question using Burkholderia as a model genus. The genus Burkholderia (ß-Proteobacteria) comprises over 50 species that are characterized by a very versatile metabolism and broad ecological amplitude. Burkholderia sp. are typical soil and rhizosphere inhabitants and engage in a variety of interactions (both mutualistic and parasitic) with other organisms (plants, fungi, animals, humans). We have accumulated evidence that Burkholderia sp. are among those populations that become dominant in acidic soils and we want to investigate the underlying mechanisms responsible for this dominance.The goals of this project are:i)to evaluate the role of acid tolerance in the biogeography of the genus Burkholderiaii)to assess the species-specificity of the acid toleranceiii)to investigate the mechanisms leading to acid toleranceIn order to reach these goals, we plan the following experiments/analyses:i)Taking advantage of an available soil DNA sample collection of continental scale (98 soil DNA samples from across North and South America), we will analyze the dominance of Burkholderia sp. using a quantitative PCR approach. The intra-generic specificity of the acid tolerance will be evaluated by cloning-sequencing of 16S rRNA and recA genes in a subset of samples.ii)The existence of a causal link between low pH and Burkholderia dominance will be tested using a microcosm design allowing for pH manipulation. Changes in Burkholderia abundance and species diversity will be monitored using the same methods as mentioned for i). In addition, Burkholderia strains will be isolated, identified and submitted to low pH tolerance in vitro assays.iii)Tolerance mechanisms will be elucidated by using a combination of molecular analyses (taking advantage of available tools, e.g. a transposon mutant bank and other Burkholderia mutants in putative acid tolerance factors) and of physiological tests on our vast Burkholderia strain collection (growth in low pH media, competition experiments with other soil/rhizosphere strains).This project will lead to a better understanding of the biogeography of the Burkholderia genus and provide valuable information for a broader audience (e.g. for Burkholderia species of agronomical or clinical relevance). Moreover, it will bring the first step towards an understanding of the mechanisms underlying low pH tolerance in Burkholderia sp., a question that has not yet been addressed at all.