Alexandra Blanchard

Transversal skills:

• Responsabilities: respresenting of PhD students in unit councils, management of molacular biology products (substitute), development of cards of risks related to molecular biology activities ("single document" INRA)

• Collaborations:
  SCRI (Scottish Crop Research Institute) in Dundee (Scotland): development of BAC and cDNA libraries of Globodera pallida
  
  BTI (Boyce Thompson Institute for plant  research) in New York (USA): send of material (RanBPM PCR products and clones) to test the involvment of RanBPM in hypersensitive reaction response
  

• Supplementary trainings:
  Creation of scientific posters (2 days), management (30h), technical and scientific communication (French/English) (30h), English (60h), population and ecosystem biology course (10h, master level), molecular evolution and phylogeny course (20h, master in bioinformatics

Teaching and supervivion experience:

Teaching

2006-present  Work practice of plant physiology (144h) - Rennes University (France)

2006                Work practice of applied zoology, an introduction to the nematology (4h) -
                        Agrocampus Rennes (France)

2005-2006       Course of nematology: plant/nematode interactions and biotechnologies.
                        Masters classes (8h) - Agrocampus Rennes (France)

2005                Talk on research jobs in National Institute of Research and Agronomy (INRA) (2h)
                        Agricultural College, Rennes (France)

Supervision:

2006                Trainee of postgraduate degree's (6 month)



Languages:

French (native language), English (near fluent), Spanish and German (basic).

Abstract:

The cyst nematodes of the Globodera genus are telluric organisms that exclusively parasite the Solanaceous botanic family. During compatible interaction, the second stage larvae hatch in the soil and move towards the apical parts of the roots where they penetrate. They then migrate intracellularly to the central cylinder. They elaborate an intimate relationship called syncytium which allows them to feed and complete their life cycle. This structure is the result of a genetic reprogramming of plant cells. The molecular bases of the plant/nematode interaction are relatively unknown but could largely improve our knowledge on the phytoparasitic nematodes. We first chose to characterise new pathogenicity genes. The description of the variability of these genes seemed to be necessary to understand their evolution. This approach should make it possible to identify the selective constraints to which they are subjected and which define to some extent the adaptive capacities of some species, populations or genera.

We isolated three new pathogenicity genes in Globodera pallida for which transcripts were localised in salivary glands, corresponding to proteins secreted by the nematode in the plant. Among these genes, we highlighted for the first time in G pallida a RanBPM homolog, Gp-rbp-1, specifically expressed at the pre parasitic and parasitic stages which lead to the development of the syncytium. Southern blot results suggest that this gene belongs to a multigenic family. The extent of the variability of this gene family was studied by screening a G. pallida cDNA library: 12 different RanBPM copies were sequenced and showed a 52.7% nucleotidic variability. Preliminary analysis of the substitutions positions for the three genes highlighted a high mutation rate on first and second codon position (~ 50%) suggesting a high proportion of non synonymous substitutions. However, the analyses will have to be carried out on a broader data set, as we did for two other genes for which we had more indications on their implication in parasitism.

Among many genes of the literature, we chose one gene involved in the early steps of parasitism, the pectate lyase gene, and one involved in the late stages, the cathepsin L gene. The elongation factor 1a, a priori not related to the parasitism, was used as a comparison. We amplified these three genes in 40 populations of cyst nematodes. After checking of the orthology of the sequences, we have shown that the same variability was observed whatever the gene considered, even if the calculated genetic distances showed an increase of the evolutionary tempo on parasitism genes. Substitutions observed in the first two positions of the codon were much more important for parasitism genes (50%) that for the housekeeping gene (20%). Sharp Analyses of the selection pressures made it possible to show that particular populations and species showed evolution rates more important that the others, even if we do not have any biological explanation for that. Moreover, we showed that the cathepsin L gene possesses a domain subjected to positive selection, indicating a strong evolutionary potential of this gene. 

Alexandra BLANCHARD
Doctor in Biology
Molecular biologist specialised in plant/pathogen interactions studies

Career accomplishments:

2006-2007        Temporary Attached to Education and Research (ATER) in
                          Rennes 1 University, France

2003-2006        PhD research in Nematology laboratory in the National Institute
                         of Agronomical Research (INRA) in Rennes, France
                         Supervisor: Eric Grenier
                         Identification, polymorphism and molecular evolution of pathogenicity
                         genes in the potato cyst nematode Globodera pallida

                                 Online access to the pdf of the manuscript: http://hal.archives-ouvertes.fr/view_by_stamp.php?label=INRA&langue=fr&action_todo=view&id=tel-00132028&version=1

2002-2003        Postgraduate degree in Nematology laboratory in INRA in
                         Rennes,France
                         Supervisor: Eric Grenier
                         Study of five transcripts differentially expressed between two cyst
                         nematodes Globodera pallida and G. "mexicana"

2001-2002        Master's degree in Plant Physiology and Pathology laboratory in Nantes
                         University, France
                         Study of resistance of recombining lines (HA89 x LR1) of
                         sunflower (Helianthus annuus) to Orobanche cumana, and essay of
                         callogenesis of Orobanche ramosa

Education:

2003-2006       PhD in Biology, Rennes 1 University, France

2002-2003       Postgraduate degree (DEA) in Genetic, Adaptation and Plant Productions
                        with a speciality in plant/pathogen relationships

2001-2002      Master's degree in Celluar Biology and Physiology, Nantes University, France
                       Speciality in Phytopathology

Scientific communications:

Publications

• Blanchard A, Esquibet M, Fouville D and E Grenier. Ranbpm homologues genes characterised in the cyst nematode Globodera pallida and G. "mexicana". Physiological and Molecular plant Pathology 67:15-22.
  Pdf: Blanchard_2005
  

• Blanchard A, Fouville D, Esquibet M, Mugniéry D and E Grenier. Sequence polymorphism of two pioneer genes expressed in phytoparasitic nematodes showing different host ranges. Journal of Heredity, in press.

• Blanchard A and E Grenier. Variability and selective constraints of the cathepsin L gene during the evolution of plant parsitic nematodes of the Heteroderidae family. Submitted.
  

• Blanchard A, Fouville D, Plantard O and E. Grenier. Characterisation and molecular evolution analysis of a new pectate lyase gene in cyst nematodes belonging to the Heteroderidae family. In prep.
  

Congress

• Blanchard A, Esquibet M, Fouville D and E Grenier. Four new Globodera genes putatively involved in plant-nematode intercation (Poster). XXVII ESN Symposium, June 2004, Rome, Italy. Pdf:

• Grenier E, Blanchard A, Esquibet M, Fouville D. Identification and polymorphism of new potato cyst nematod genes putatively involved in plant-nematode interaction (Poster). Conférences Jacques Monod "Ecology and evolution of host-parasite relationships", September 2004, Roscoff, France.

• Blanchard A, Pylypenko L, Thirugnanasambandam A, Blok V, Chapman S, Grenier E, Lilley C, Neatham J, Phillips M and JT Jones. Characterisation on a ranbpm multigene family from ESTs of Globodera pallida (Talk). 58th International symposium on crop protection, May 2006, Gent, Belgium.

• Blanchard A, Fouville D, Esquibet M and E Grenier. Evolution of parasitism genes among the cyst nematodes (Talk). XXVIII ESN symposium, June 2006, Blagoevgrad, Bulgaria.

• Blok V, Chapman S, Armstrong M, Phillips M, Lilley C, Urwin P, Blanchard A, Grenier E and JT Jones. Genomic analysis in the potato cyst nematode Globodera pallida (Talk). APS-CPS-MSA joint meeting, July-August 2006, Quebec city, Canada.

• Blanchard A, Castagnone P, Rosso MN, Fouville D and E Grenier. Evolution of parasitism genes in Heteroderidae plant parasitic nematodes family (Poster and Talk). XX Evolutionary biology meeting, september 2006, Marseille, France.

Technical skills: