Université d'Orléans

Assistant lecturer in Animal and Plant Biology (2012-2013)

University of Orléans, UFR-Faculté des Sciences (France)

Teaching activity

- Practical and theoretical sessions in Cellular Biology

- Practical sessions in Animal Biology: parasitology

- Practical and theoretical sessions in Plant Biology: seaweeds and fungi

- Practical and theoretical sessions in Informatics: IT and internet certificate

PhD position (2009-2013)

Supervised by Dr S. Carpin (co-supervisor Dr F. Héricourt)

Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), University of Orléans (France)

PhD subject

The signal perception and transduction systems allow plants to survive to environmental conditions changes by reacting quickly and efficiently to variety of important stimuli. The multistep phosphorelay system is one of them and is involved in several environmental and developmental regulatory pathways. This system enables plants to respond to dehydratation stress and plant hormone signaling regulation in particular cytokinin.  In Arabidopsis thaliana, the multistep phosphorelay is composed of three types of signaling protein families: membrane-bound sensor Histidine-aspartate Kinases (AHKs), Histidine-containing Phosphotransfer proteins (AHPs) and Response Regulators (ARRs). In response to interaction between cytokinin molecules and the N-terminal extracellular sensory CHASE domain of HKs, cytokinin receptors initiate an autophosphorylation on their histidine-containing transmitter domain and the phosphate residue is then relayed firstly to their aspartate-containing receiver domains. Then, the AHPs receive the phosphate signal on their specific histidine residue, and initiate the downstream transfer of phosphate to aspartate residues of RR proteins, more precisely B-type ARRs acting as transcription factors and constituting the final outpout of cytokinin pathway.

In addition to cytokinin signaling, the multistep phosphorelay system is also involved in the osmosensing in Arabidopsis, and we focus our work on this pathway in poplar.

My PhD subject is focused on the multistep phosphorelay partners probably involved in the osmotic stress perception induced by dehydratation, and is composed of 2 parts:

Identification of osmosensing pathway members

We identified members similar to the one found in Arabidopsis as the Histidine-aspartate Kinase HK1, ten HPts and eight B-type RRs. HK1 is able to function as osmosensor in yeast. By interaction studies in yeast (two-hybrid) and in planta (Bimolecular Fluorescence Complementation: BiFC) combinated with transcripts expression analyses in planta, we identified the downstream partners HPts and B-type RRs of HK1. Three HPts (HPt2, HPt7 and HPt9) and five B-type RRs (RR12, 13, 14, 16, and 19) appeared as preferential partner of HK1. The cellular localization of these different members has been also showed: localization at the plasma membrane of HK1, nucleo-cytoplasmic and nuclear of HPts and B-type RRs respectively. In addition, the HPts/B-type RR interactions occurred in the nucleus of the cell.  

Functional characterization of B-type RR13, and its involvement in the osmosensing pathway

We will show the role of this RR as transcription factor allowed responses to osmotic stress. We will study the possible interaction between this RR and the promoter of response genes in planta by transactivation. In vitro experiments will allow us to confirm the DNA binding domain already defined and validate interaction of this B-type RR on response genes promoters. This study will be completed by a transcriptional regulation study to improve our knowledge about genes regulated by osmotic stress using the technique of real time PCR.

Publications

Bertheau Lucie, Françoise Chefdor, Grégory Guirimand, Vincent Courdavault, Christiane Depierreux, Domenico Morabito, Franck Brignolas, François Héricourt, and Sabine Carpin (2012) Identification of five B-type response regulators as members of a multistep phosphorelay system interacting with histidine-containing phosphotransfer partners of Populus osmosensor. BMC Plant Biology 12:241. doi:10.1186/1471-2229-12-241

Héricourt François, Françoise Chefdor, Lucie Bertheau, Mirai Tanigawa, Tatsuya Maeda, Grégory Guirimand, Vincent Courdavault, Mélanie Larcher, Chrstiane Depierreux, Hélène Bénédetti, Domenico Morabito, Franck Brignolas and Sabine Carpin (2013) Characterization of histidine-aspartate Kinase HK1 and identification of histidine phosphotransfer proteins as potential partners in a Populus multistep. Physiologia Plantarum. doi:10.1111/ppl.12024

Communications

Oral Communications

Seminar

2012

University of Molise, Pesche, Isernia (Italie)

L. Bertheau, F. Chefdor, F. Héricourt, C. Depierreux, D. Morabito, F. Brignolas, S. Carpin. Identification of 4 B-type response regulators as members of a multistep phosphorelay system interacting with Histidine-containing Phosphotransfer partners of Populus osmosensor.

University of Firenze (Italie)

L. Bertheau, F. Chefdor, F. Héricourt, C. Depierreux, D. Morabito, F. Brignolas, S. Carpin. Identification of 4 B-type response regulators as members of a multistep phosphorelay system interacting with Histidine-containing Phosphotransfer partners of Populus osmosensor.

2011

University of Molise, Pesche, Isernia (Italie)

L. Bertheau, F. Chefdor, F. Héricourt, C. Depierreux, D. Morabito, F. Brignolas, S. Carpin. Response regulators involved in the osmosensing signaling pathway in Populus.

University of Firenze (Italie)

L. Bertheau, F. Chefdor, F. Héricourt, C. Depierreux, D. Morabito, F. Brignolas, S. Carpin. Response regulators involved in the osmosensing signaling pathway in Populus.

International congress

2011

International Symposium on Plant Biotechnology towards tolerance to stresses and enhancing crop yield (ISPB), Ranchi, Jharkhand (India)

L. Bertheau, F. Chefdor, F. Héricourt, C. Depierreux, D. Morabito, V. Courdavault, G. Guirimand, F. Brignolas, S. Carpin. Characterization of poplar response regulators as potential partners of HPt proteins in a multi-step phosphorelay system.

Molecular basis of plant stress, Varna (Bulgary)

L. Bertheau, F. Chefdor, F. Héricourt, C. Depierreux, D. Morabito, M. Tanigawa, T. Maeda, G. Guirimand, V. Courdavault, F. Brignolas, S. Carpin. Identification and characterization of the three partners of a multi-step phosphorelay probably involved in poplar osmosensing.

International workshop (Resurrection Plants in the Era of Global Warming), University of Rouen (France)

L. Bertheau, F. Chefdor, C. Depierreux, F. Héricourt,  S. Carpin. Osmosensing in Populus: possible involvement of a multi-step phosphorelay.                                     

Poster Communications

2012

International Conference on Plant Abiotic Stress Tolerance II (PASTII), Vienna (Austria)

L. Bertheau, F. Chefdor, F. Héricourt, V. Courdavault, G. Guirimand, C. Depierreux, D. Morabito, F. Brignolas, S. Carpin. Osmosensing in Populus:  Characterization of B-Type Response Regulators as Third Partner.

2010

XVII congress of the Federation of European societies of plant biology (FESPB), Valencia (Spain)                         L. Bertheau, F. Chefdor, F. Héricourt, G. Guirimand, V. Courdavault, C. Depierreux, D. Morabito, F. Brignolas, S. Carpin. Subcellular localisation of HPt proteins and research of Response Regulators involved in the osmosensing signaling pathway in Populus.

2009

Third SMBBM international congress of  biochemistry, IUBMB special meeting on plant stresses & 6 th. FASBMB congress, Marrakech (Marocco)

L. Bertheau, C. Depierreux, F. Chefdor, F. Héricourt, D. Auguin, F. Brignolas, S. Carpin. Expression analysis of a gene encoding a putative osmosensor in Populus.

International Conference on Plant abiotic stress tolerance, Vienna (Austria)

L. Bertheau, C. Depierreux, F. Chefdor, F. Héricourt, D. Auguin, F. Brignolas, S. Carpin. Expression analysis of a gene encoding a putative osmosensor in Populus.

Collaborations

Dr. Vincent Courdavault, EA2106 Biomolécules et Biotechnologies Végétales, Tours, France

Dr. Audrey Oudin, EA2106 Biomolécules et Biotechnologies Végétales, Tours, France

Dr. Gaëlle Glévarec, EA2106 Biomolécules et Biotechnologies Végétales, Tours, France

Pr. Gabriella Stefania Scippa, Dipartimento di  Bioscienze  e  Territorio,  Università degli  Studi  del  Molise, Pesche, Italy

University Degrees

2009-2012 PhD, University of Orléans, LBLGC

University contract for teaching in plant Biology for Undergraduate levels (192 h)

- Practical sessions in Plant diversity, seaweeds and fungi

- Practical sessions in Molecular Biology: signal transduction pathway

2008-2009 MSc Terrestrial Ecosystem and Human Action, University of Orléans, LBLGC

Research training: "Expression regulation study of HK1 in poplar calli submitted to different osmotic stresses"

2006-2008 BSc Biology and Ecology of Organisms, University of Orléans, LBLGC

Research training: "Expression regulation study of HK1 in poplar calli submitted to different osmotic stresses: perfecting of experimental conditions"

"Construction of a fusion protein HPt2-GFP"

2004-2006 Undergraduate General Diploma in Biology, University of Orléans