Visiting Scientists : Andrea Genre seminar

Andrea Genre is associate professor in Plant Biology at the University of Turin. Since his PhD, his research interests have been focused on the molecular/cellular bases of plant-fungal interactions in mycorrhizal symbioses. He is currently investigating the plant pathways involved in the perception of symbiotic fungal signals and the cellular processes underlying host cell reorganization during intracellular accommodation of arbuscular mycorrhizal fungi. Dr. Genre is also coordinating a research project aimed at improving the symbiotic status of forage plants.

The majority of terrestrial plants form mutually beneficial associations with ubiquitous arbuscular mycorrhizal (AM) soil fungi, resulting in significantly improved mineral nutrition for the host plant. To establish this symbiosis, the AM fungus penetrates the root epidermis and develops specialized symbiotic structures called arbuscules within cells of the root cortex which are the major sites for nutrient exchange. The initiation of this ancient and ecologically important root endosymbiosis depends on a complex and poorly understood molecular dialogue between the two partners which results in the activation of a highly conserved calcium-dependent signaling pathway in host epidermal cells. The triggering of this symbiosis-specific pathway in response to AM fungal symbiotic signals is essential for subsequent entry of the fungus into the root tissues.

Recent findings from several laboratories point to a likely role for chitin-based fungal signals in this initial recognition step, and indeed novel findings from a fruitful collaboration between Dr. Andrea Genre (U. Torino) and two TULIP Labex teams (members of the LIPM and LRSV) point to a key role for short-chain chitin oligomers within this fungal-plant dialogue. Additional experiments are now underway to further examine this question following the intriguing and unexpected discovery that the rice receptor component OsCERK1, known to mediate host immune responses triggered by long-chain chitin elicitors, is also required for establishing the AM association. The main objective of the visit of Dr. Genre is to pursue studies aimed at revealing the identity of the fungal chitin-based molecules which are responsible for the activation of the symbiotic signaling pathway in rice.