New ZealandCountry of destination:
Rhizobia are a large family of bacteria that are able to establish a nitrogen-fixing symbiosis with legume plants. Over the course of evolution, the ability to interact symbiotically with plants spread among different bacterial genera, including to previously pathogenic bacteria. This spread required the horizontal transfer of key symbiotic genes as a first step, but additional genetic modifications are required for the recipient bacteria to become nitrogen-fixing mutualists. The genetic and selective conditions underpinning this second step of the evolution of rhizobial symbionts are still unclear. To replay the evolution of new rhizobia, the host team has initiated an evolution experiment by transferring symbiotic genes into a bacterial pathogen, and evolving this chimeric strain under plant selection pressure. In the course of this experiment, bacteria greatly improved their ability to form nodules and infect plant cells. Several adaptive mutations responsible for these phenotypic changes have been identified but their effect on bacterial transcriptome within plant nodules is unknown. It is also unknown how plant nodule transcriptional programme is regulated in the course of bacterial evolution. In this project, I will employ dual RNA-sequencing to characterize transcriptomes of both partners - plant nodules and evolved bacteria - during the symbiotic interaction. It will allow us to understand to which extend adaptive mutations re-organize bacterial transcriptional programmes, and will also shed light on how plant responses (in particular, immunity and developmental responses) accompany and shape the evolution of new bacterial symbionts.
I am a microbiologist with a particular interest in evolutionary genetics. My general approach is to use experimental evolution to investigate the genetic and selective causes of bacterial adaptation to various conditions. I received my PhD in 2011 from University Paul Sabatier in Toulouse, France. My PhD work was carried out at the Laboratory of Plant-Microbe Interactions (LIPM) and focused on the evolution and function of a family of secreted virulence effectors from the plant pathogenic bacterium Ralstonia solanacearum. I then joined the team of C. Masson, still at LIPM, for a first post-doc to work on an experimental evolution project aiming at evolving a plant symbiotic bacterium from a pathogenic one. My specific contribution was directed to understand the origin and consequences of a transient hypermutagenesis phenomenon that had been identified during this experiment. In 2013, I moved to New Zealand and joined the team of Paul Rainey to expand my skills in experimental evolution. There, I investigated the genetic bases of phenotypic heterogeneity in the bacterium Pseudomonas fluorescens, and studied the evolution of multicellularity. I am currently back at LIPM as part of my AgreenSkills mobility project.
Daubech B.*, P. Remigi*, G. Doin de Moura, M. Marchetti, C. Pouzet, M.C. Auriac, C.S. Gokhale, C. Masson-Boivin and D. Capela. 2017. Spatio-temporal control of mutualism in legumes helps spreading symbiotic nitrogen fixation. eLife. 6:e28683. Doi: 10.7554/eLife.28683. (* denotes first co-authorship)
Farr A., P. Remigi and P.B. Rainey., 2017. Adaptive evolution by spontaneous domain fusion and protein relocalisation. Nature Ecology and Evolution. 1: 1562-1568. Doi:10.1038/ s41559-017-0283-7.
Gallie J., E. Libby, F. Bertels, P. Remigi, C.B. Jendresen, G.C. Ferguson, N. Desprat, M.F. Buffing, U. Sauer, H.J.E. Beaumont, J. Martinussen, M. Kilstrup, and P.B. Rainey. 2015. Bistability in a metabolic network underpins the de novo evolution of colony switching in Pseudomonas fluorescens SBW25. PLOS Biology 13(3):e1002109. Doi: 10.1371/journal.pbio.1002109.
Remigi P., D. Capela, C. Clerissi, L. Tasse, O. Bouchez, J. Batut, S. Cruveiller, E.P.C. Rocha and C. Masson-Boivin. 2014. Transient hypermutagenesis accelerates the evolution of legume endosymbionts following horizontal gene transfer. PLOS Biology 12(9):e1001942. Doi: 10.1371/journal. pbio.1001942.
Remigi P., M. Anisimova, E. Wicker, S. Genin, N. Peeters. 2011. Functional divergence of the GALA family of typethree effectors from the phytopathogenic bacterium Ralstonia solanacearum. New Phytologist, 192:976-987.