Biogeography and evolution of plant-microbe interactions

Adjunct professor
Department of biological sciences - University of Montreal

Botanist and researcher
Montreal Botanical Garden


Understanding the origins and consequences of global microbial diversity represents a priority for biologists of the 21st century. From improving human and plant health to maintaining air, water and soil quality, the applications of research in microbial ecology are particularly relevant to answer to the great environmental challenges of our time.

My research at IRBV aims to understand the ecological and evolutionary mechanisms underlying the associations between plants and their leaf microbes. Namely, my laboratory is interested in understanding which types of microbes live at the surface of leaves and within them, and which adaptations allow them to survive in these habitats. We combine conceptual and experimental approaches to ask these questions, namely ones based on the traits of organisms and their phylogenetic relationships. We are also interested in the ways in which the plant microbiome can prevent the emergence and spread of plant diseases at the Botanical garden of Montreal.

Keywords: Plant and microbial ecology Host-symbiont associations Population and community ecology Genomics Bioinformatics Functional traits and phylogenetics


Ph.D. students
Mobina Gholamhosseini, co-supervision with Anne Bruneau

M.Sc. students
Laurine Dariel


  • Lajoie, G. and Parfrey, L.W. Beyond specialization: re-examining routes of host influence on symbiont evolution. Accepted. Trends in Ecology and Evolution.
  • Lajoie, G. and Kembel, S.W. 2021. Plant-bacteria associations are phylogenetically structured in the phyllosphere. Molecular Ecology. 30: 5572-5587.
  • Lajoie, G. and Kembel, S.W. 2021. Host neighborhood shapes bacterial community assembly and specialization on tree species across a latitudinal gradient. Ecological Monographs. 91: e01443.
  • Rivest, S., Lajoie, G., Watts, D. and Vellend, M. 2021. Earlier spring reduces potential for gene flow via reduced flowering synchrony across an elevational gradient. American Journal of Botany. 108: 538-545.
  • Lajoie, G., Maglione, R. and Kembel, S.W. 2020. Adaptive matching between phyllosphere bacteria and their tree hosts in a neotropical forest. Microbiome. 8: 70.
  • Malaterre, C., Dussault, A.C., Rousseau-Mermans, S., Barker, G., Beisner, B.E., Bouchard, F., Desjardins, E., Handa, I.T., Kembel, S., Lajoie, G., Maris, V., Munson, V., Munson, A., Odenbaugh, J., Poisot, T., Shapiro, B.J., Suttle, C.A. 2019. Functional diversity: An epistemic roadmap. BioScience. 69: 800-811.
  • Lajoie, G. and Kembel, S.W. 2019. Making the most of trait-based approaches for microbial ecology. Trends in Microbiology, 27: 814-823.
  • Lajoie, G. and Vellend, M. 2018. Characterizing the contribution of plasticity and genetic differentiation to community-level trait responses to environmental change. Ecology and Evolution, 8: 3895-3907.
  • Houle D., Lajoie G. and Duchesne L. 2016. Major losses of nutrients following a severe drought in a boreal forest. Nature Plants, 2: 16187.
  • Lajoie G. and Vellend M. 2015. Understanding context dependence in the contribution of intraspecific variation to community trait-environment matching. Ecology, 96: 2912-2922.
  • Vellend M., Lajoie G., Bourret A., Múrria C., Kembel S.W., and Garant D. 2014. Drawing ecological inferences from coincident patterns of population- and community-level biodiversity. Molecular Ecology, 23: 2890-2901.