Olivier GODFROY

En résumé

Entreprises

• Station biologique de Roscoff - Chercheur Post-doctorant - Ingénieur de recherche

  2008 - 2014 Creation of a reverse genetic tool for the model brown alga Ectocarpus :
  Since the release of the complete genome sequence in 2010, Ectocarpus has been adopted as a model organism for the brown algae. An important effort has been put into the development of several functional genomics tools. In this context, I set up a complete protocol to establish a reverse genetic tool based on the TILLING approach which has been widely used for land plants. I developed a chemical mutagenesis protocol and evaluated it against classical UV mutagenesis (1). I, then, generated a mutant population of more than 4000 mutant lines. Using high throughput molecular biology techniques, multi-dimensional pooling strategies and Next Generation Sequencing approaches, I conceived and tested a facility to identify individuals affected in targeted genes of interest, within this 4000 line population.
  
  Understanding the genetic network that controls alternation between the gametophye and sporophyte generations in Ectocarpus :
  Ectocarpus has a typical haploid-diploid life cycle which involves alternation between gametophye and sporophyte generations. Using forward genetic approaches, we isolated and characterized several individuals that exhibit a modification of this alternation of generations. I was involved in the detailed characterization of two of these mutants which have completely lost the sporophyte generation. I mainly brought expertise in QRT-PCR in order to complete the molecular characterization of the oro mutant (2) ; and performed genetic mapping of a second gene.
  
  Identification and characterization of the distag Ectocarpus mutant :
  Mutagenesis experiments have also allowed the isolation of mutant with altered patterns of development. One particularly interesting example is the distag mutant, which completely lacks attachment structures. I was involved in the phenotypic characterization of this mutant and I identified the causal mutation using a SHOREmap-based approach (3).
  
  (1)Godfroy O., Coelho SM. and Cock JM “Genome-wide comparison of ultraviolet and ethyl methanosulphonate mutagenesis methods for the brown alga Ectocarpus.” in preparation
  (2)Coelho SM., Godfroy O., Arun A., Le Corguillé G., Peters AF. and Cock JM. (2011) “OUROBOROS is a master regulator of the gametophyte to sporophyte life cycle transition in the brown alga Ectocarpus.” Proceedings of The National Academy of Sciences 108(28):11518-11523.
  (3)Godfroy O., Uji, T., Lipinska, A., Peters AF., Cock JM and Coelho SM. “DISTAG controls initiation of the basal system of the brown alga Ectocarpus sp.” in preparation

• INRA-CNRS-Université de Paul Sabatier TOULOUSE 3 - PhD in Plant Biotechnology

  2004 - 2008 The objective of my PhD was to better understand the role of the DMI3 protein in the signalling pathway controlling the establishment of two different root symbioses, the vesicular arbuscular endo-mycorrhizal symbiosis and the rhizobium-legume nitrogen fixing symbiosis. I analyzed the spatial and temporal expression pattern of the DMI3 gene during both symbioses. DMI3 is the last known gene necessary for both mycorrhizal and nitrogen fixing symbioses. The Medicago dmi3 null-mutant was complemented by introducing a non-legume DMI3 homologue, in order to investigate the role of this protein in the acquisition of the ability to establish the rhizobium-legume symbiosis (4).
  I was also interested in the RPG gene, which is implicated in the processes whereby the plant controls root invasion by the symbiont during the establishment of the rhizobium nitrogen fixing symbiosis. I determined the in vivo expression pattern of the RPG gene and elucidated the subcellular localization of the RPG protein using a gene fusion with fluorescent protein and transient expression in a heterologous system (5).
  
  (4)Godfroy, O., Debellé, F., Timmers, T. and Rosenberg, C. (2006). “A Rice Calcium- and Calmodulin-Dependent Protein Kinase Restores Nodulation to a Legume Mutant.” Molecular plant microbe interactions 19(5): 495-501.
  (5)Arrighi, J.F., Godfroy, O., De Billy, F., Saurat, O., Jauneau, A., and Gough, C. (2008) “The RPG gene of Medicago truncatula controls Rhizobium-directed polar growth during infection.” Proceedings of The National Academy of Sciences 105(28): 9817-9822.

Formations

• Université De Bourgogne M2R BBCM

  Dijon 2003 - 2004 DEA
  
  mention AB
  
  Seddas PM, Arias CM, Arnould C, van Tuinen D, Godfroy O, Benhassou HA, Gouzy J, Morandi D, Dessaint F and Gianinazzi-Pearson V. (2009) “Symbiosis-related plant genes modulate molecular responses in an arbuscular mycorrhizal fungus during early root interactions.” Molecular plant microbe interactions 22(3):341-351.

• Université Tours Francois Rabelais

  Tours 2001 - 2003 Licence-Maitrise
  
  mention AB

Réseau

• Decou RAPHAËL

• Evelyne HENNINGER-MAUSSANT

• Guillaume HATTE