Plant-symbiotic fungi influence the structure of ecosystems, but factors shaping species distributions in time and space are seldom understood. In our work on palm trees Astrocaryum sciophilum, we have observed that the young unopened leaves are colonized with endophytic bacteria only, and that fungi progressively replace the bacteria as the leaves get older.

  1. What are the schemes of colonization of leaves by fungi? What is the distribution of endophytic bacteria and fungi as leaves age?
  2.  By which mechanisms fungi replace bacteria? What are the biological targets of fungal metabolites? Do fungi produce bacteriotoxic compounds only or do they act on other targets (bacterial quorum sensing for example)?
  3. How do fungi overcome the development of chemoresistant bacteria?
  4. Can these mechanisms inspire the discovery of new efficient antibacterial agents or a combination of them?

We will undertake an investigation of the two model systems Astrocaryum sciophilum and Posidonia oceanica.