Alexandre DE SAINT GERMAIN Research Scientist

Research Scientist | Strigolactones and Allelochemicals Signaling

I am associate researcher at INRAE in the SAS team since 2020. My work on allelopathy aims to decipher the genetic and molecular mechanisms of underground chemical communications between plants, in particular by focusing on the mechanism of Strigolactone perception.
I studied at Sorbonne University (UPMC) in order to become biology teacher. After obtained my "agrégation" diploma, I continued in Master 2 to deepen my knowledge in plant physiology. In 2009, I did my M2 internship at the IJPB with Catherine Rameau, who had just participated in the identification of the strigolactones function as plant hormones controlling shoot branching. I then became fascinated by this family of amazing molecules, at the same time phytohormones and allelopathic compounds exuded by plant roots to stimulate the establishment of mycorrhizal symbiosis and the germination of parasitic seeds plants. Since, strigolactones will remain at the heart of my research activities.

I did my thesis from 2009 to 2012 under the supervision of Catherine Rameau on the strigolactones signaling pathway. I showed, on the pea model, that the transcript level of the transcription factor, PsBRC1, the homolog of TEOSINTE BRANCHED 1, is regulated by strigolactones and allows to control plant branching.  

Between 2013 and 2016, I continued on the characterization of the putative strigolactone receptor, as post-doctoral fellow at the SALK Institute, USA, in the laboratory of Joanne Chory. In collaboration with François-Didier Boyer from ICSN (CNRS/UPSaclay, Gif-sur-Yvette) I have identified an original perception mechanism in which the receptor performs an irreversible enzymatic reaction to generate its own ligand. After one year as an ATER at IBPC on nucleo-chloroplastic communication, I did between 2017 and 2020 a second postdoc at IJPB, on strigolactone perception evolution in Physcomitrium patens (collaboration Sandrine Bonhomme, IJPB) and Phelipanche ramosa (collaboration Philippe Delavault, Université de Nantes).  

Today, I am combining plant physiology, genomics, biochemistry and analytical chemistry approaches to determine the genetic basis of plant-plant interactions at the rhizosphere level, and try to identify new allelopathic compounds. Understanding these mechanisms could be used in agriculture to develop new agroecological approaches, in particular to limit the use of herbicides.
Alexandre De Saint Germain


Strigolactones and Allelochemicals Signaling

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Tél : 0130833183