Simon Bernard Saucet

Simon Bernard Saucet

AgreenSkills session, year: 2nd session, 2016

Receiving laboratory: ISA, Sophia Agrobiotech Institute, PACA, Antibes, Sophia Antipolis

Country of origin : Japan




Mobility project

Investigation into the molecular mechanisms underlying nematode recognition by the Ma resistance protein in the roots of a woody perennial plant

The root-knot nematodes (RKNs) Meloidogyne spp., represent a global threat for annual and perennial crops causing huge crop losses worldwide. Several genes encoding nucleotide-binding (NB) and leucine-rich repeat (LRR)-containing receptor (NLRs) have been isolated for their ability to provide resistance to RKNs. NLRs are intracellular receptors able to detect secreted pathogenic proteins known as effectors, through direct or indirect interaction. Various studies describe the roles of NLRs’ protein domains and how they act at intra- and intermolecular levels for receptor activation and downstream signalling. However, their function for up- and downstream signalling is poorly known and particularly in regards to the large number of NLRs identified in plants, the additional domains they often possess, as well as the diversity of NLRs architecture. The gene Ma, from the Toll/Interleukin 1 receptor (TIR)-NB-LRR (TNL) family, has been cloned from the plum Prunus cerasifera where it confers a high resistance against numerous RKN species. In addition to the core TNL structure, Ma has a large extension in C-terminal encoded by five repeated exons. Interestingly, a single post-LRR (PL) exon, encoding a domain with conserved motifs, is frequently present in plants TNLs. We are investigating how this repeated PL domain in Ma participates to RKNs resistance in Prunus. Using the modular Golden Gate cloning method, I will test Ma truncated versions and chimeras for their ability to provide RKNs resistance in transgenic Prunus roots. Characterization of Ma’s PL domains at intra and intermolecular levels will enable us to reveal the function of this conserved immune region and, ultimately, to contribute to the development of methods to control RKNs infection in crops.

Biography & research interests

Plans are fascinating organisms. They have a great capacity to evolve a wide range or organs and molecular mechanisms in order to adapt to their environment. During my studies in France universities (La Rochelle, Nantes and Paris), I became particularly interested in plant biology. At Master level, I focused on plant immunity, an innate network of receptors and defense signalling that enable plants to recognize parasites and establish resistance. I obtained my Master degree from Paris Sud XI University after a training course of 6 month in England in professor Jonathan Jones’s laboratory. I had the great opportunity to pursue my research at The Sainsbury Laboratory, as a PhD student, under prof Jones’s supervision. During my PhD, I studied the TNL resistance protein pair RRS1B/RPS4B and how it functions to recognize bacterial effectors and activate defense. I received my PhD degree in 2014 from the Biological School of the University of East Anglia. After a short post-doc in France in the Institut Sophia Agrobiotech (ISA), I received a JSPS fellowship to work as a post-doc in Ken Shirasu’s laboratory in Japan. There, I studied for two years the molecular factors that determine how parasitic plants do not spontaneously parasitize themselves and, in the other hand, how they produce virulence factors for successful parasitism of host plants. I then obtained an Agreenskills+ fellowship to return to ISA in France in Daniel Esmenjaud’s laboratory. Since May 2017 I conduct research on the Ma gene and its molecular function for nematode resistance.

Selected publications

Saucet SB & Shirasu K (2016). Molecular parasitic plant-host interactions. PLOS Pathogen, accepted;

2*. Saucet SB, Van Ghelder C, Abad P, Duval H & Esmenjaud D (2016). Resistance to root-knot nematodes Meloidogyne spp. in woody plants. New Phytologist, 211:41-56;

3. Cui S, Wakatake T, Hashimoto K, Saucet SB, Toyooka K, Yoshida S & Shirasu K (2015). Haustorial hairs are specialized root hairs that support parasitism in the facultative parasitic plant, Phtheirospermum japonicum. Plant Physiology, 170:1492-1503;

4*. Sarris PF, Duxbury Z, Huh SU, Ma Y, Segonzac C, Sklenar J, Derbyshire P, Cevik V, Rallapalli G, Saucet SB, Wirthmueller L, Menke FLH, Sohn KH & Jones JDG (2015). A plant immune receptor complex is activated by bacterial effectors that target WRKY transcription factors. Cell, 161:1089-1100;

5*. Saucet SB, Ma Y, Sarris PF, Furzer OJ, Sohn KH & Jones JDG (2015). Two linked pairs of Arabidopsis TNL resistance genes independently confer recognition of bacterial effector AvrRps4. Nature Communications, DOI:10.1038/ncomms7338;

6. Williams SJ, Sohn KH, Wan L, Bernoux M, Sarris PF, Segonzac C, Ve T, Ma Y, Saucet SB, Ericsson DJ, Casey LW, Lonhienne T, Winzor DJ, Zhang X, Coerdt A, Parker JE, Dodds PN, Kobe B & Jones JDG (2014). Structural basis for assembly and function of a heterodimeric plant immune receptor. Science, 18:344:299-303;

7. Sohn KH, Saucet SB, Clarke CR, Vinatzer BA, O’Brien HE, Guttman DS & JonesJDG (2012). HopAS1 recognition significantly contributes to Arabidopsis nonhost resistance to Pseudomonas syringae pathogens. New Phytologist, 193:58-66.

Awards & patents

JSPS Post-Doctoral Fellowship for Foreign Researcher (Short-Term), 2014;
JSPS Post-Doctoral Fellowship for Foreign Researcher (Long-Term), 2015;
Special Post-Doctoral Researcher RIKEN Fellowship, 2015;
FEBS Return-to-Europe Post-Doctoral Fellowship, 2016;
Agreenskills+ Post-Doctoral Fellowship, 2016.