35th NPS abstract book

Session 4: Comparative, functional and ecological genomics
Chair: Catherine Kidner
Ectomycorrhizal fungi are playing JAZs during
symbiosis formation
S4.1
JONATHAN M PLETT 1,2 , YOHANN DAGUERRE 1 , IAN C 15:00–15.30
ANDERSON 2 , CLAIRE VENEAULT-FOURREY 3 and FRANCIS
MARTIN 1
j.plett@uws.edu.au
1 Labex ARBRE, Tree-Microbe Interactions’ department, INRA-Nancy,
Champenoux, France; 2 Hawkesbury Institute for the Environment,
University of Western Sydney, Richmond, NSW, Australia; 3 University of
Lorraine, Nancy, 54000, France
In forest ecosystems, ectomycorrhizal (ECM) fungi constitute a significant proportion of soil
microbial biomass where they form symbioses with tree roots, providing growth limiting nutrients
such as nitrogen and phosphorus to the tree in return for up to 20-30% of photosyntheticallyderived
carbon from their hosts. While colonization of roots by ECM fungi is a very invasive process
reminiscent of when pathogens take over plant tissues, in-growth of ECM fungal hyphae into roots is
typically characterized by a relatively low defense response on the part of the tree host. Our ongoing
research is beginning to uncover how the ECM fungus is able to avoid immune detection by
the plant: through the use of small secreted effector proteins. I will focus on our current
understanding of how one of these proteins, MiSSP7 encoded by the ECM fungus Laccaria bicolor,
enters poplar tree root cells and interacts with JAZ proteins – the co-receptors to the plant defense
hormone jasmonic acid (JA). Interaction between MiSSP7 and the JAZ proteins is essential for L.
bicolor colonisation of poplar roots and leads to a repression of one part of the JA signaling pathway.
I will cover our most recent findings concerning the role of JAZ proteins in poplar cellular biology as
well as our preliminary work characterizing the role of these proteins during the interaction between
Eucalyptus grandis and its ECM symbiont Pisolithus microcarpus.
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